The through hull fittings installed to break the vacuum in the trim tab pockets was a slick idea. I love this channel because it’s chock full of slick tips like that!
Never had this problem. Always knew that the engine needed to be set just right. Always had someone like you to make sure that it was done right. Great information always a pleasure to see what you are doing. 👍😎🌴 Stay safe out there.
I really enjoy your clear matter of fact style. Ive watched you and been subscribed for many month's. I live on Casco Bay in South Portland Maine. My 1998 Honda bf90 threw a connecting rod through the crankcase cover last November. But it never died as I watched its oil pump out it still idled me a mile or more to the ramp...I had no choice. My wife and I traveled to Marathon last month and stayed at the Jolly Roger RV park. I was so surprised to see your channel say that week I was so close to your Marina. On the way to Coco plum Beach I stopped in to say hi and see what you might have to replace my beloved Honda but you were closed 2 times I came by. Anyway I like your shows! Very clear! Thanks very much.
In my experience, a hard overhead roof or soft Bimini top can also contribute to the porpoising, especially if cruising into the wind and waves. One of the many reasons that I love boating, the frequent adjusting to the conditions. Thanks for another great tutorial.
Don't know how I missed this episode. Great information. My Simmons Sea Skiff has a hook on purpose. Originally I had a 70HP Tohatsu that had issues. I didn't trust a 2stroke. I repowered her with a Suzuki 60. I learned about weight distribution and she don't Porpoise no more. Alleluia. Great info, thanks
The porpoising typically happens inside of a speed range and under certain load conditions. For instance we have a pretty fast twin engine boat with a bracket which tops out well over 70mph, but under light load conditions it nearly always porpoises between 45-50mph. This is the speed range in which it begins to lift the hull out of the water and outside of that speed range it runs perfect, but inside that speed range it's unstable. Adding a few passengers to the front of the boat moves the speed range up by maybe 5mph etc. What we have is an old school "straight hull" and it's fun because you can vary the angle of attack a lot with the trim, it runs great you just have to know how to drive it. I guess the modern solution to all this is to add steps and then boat will have the same angle of attack almost not matter what you do with the trim, and no porpoising. But honestly I like my old school hull, it's fun to play with the trim and it's as fast as anything once you trim her up and open her up. But basically if have porpoising problems start with moving the weight around, you're either going to want to make the nose heavier or lighter and then play with the trim. Offshore the easy solution is typically to add more weight in the front.. but it's going to run wet. Probably.
MATHS are hard. That is why I prefer hillbilly math.....but also probably explains why my last two boats are at the bottom of the lake! Thanks for posting!!!!
Thanks guys for your content, Yes I've experienced porpoising effect, my father years ago built a bondwood boat, cabin cruiser 20foot and he decided to increase the cabin size by lengthening the aft (of the cabin not the hull) one foot. This stuffed up the balance of the boat, hence fuel and water tanks forward extra anchor chain and a refit to the cabin layout. It was a nightmare and lesson learned.
I remember the good ole days. I didn’t have to worry about brackets , trim tab pockets , four stroke motors , they didn’t exist. Trim / tilt was advanced !
Súper helpful this video I learn something new today,those hole in the back are made it to release air and let the boat get on plain faster, interesting 🤨 thanks for the video 👍
This was the most excellent simi technical explanation of hydro physics real life functions I have ever heard concerning this modification. I have been considering a repower on my 77 SeaRay 24ft sedanbridge.
Not all 'hooks' are due to age changes on boats. In the seventies and eighties on up there were boats which used the 'hook' to achieve level plane with minimum horsepower. This was emphasized after the seventies oil embargo when low horsepower boats were in demand and continued on for many years. I have also had porpoising from boats that were designed to be used with inboard power as well as I/O and outboards. They incorporated a full keel which went 3/4 of the way aft and would have been used for the shaft of an inboard. At higher speeds (27-8 knots and above) the partial keel wanted to be a planing surface but wasn't large enough to maintain so the effect was porpoising. Trim tabs helped on some but bottom line was that type of hull just had a built in speed limit. A lot of forces are increased dramatically on the hull that has been swapped over to a bracket. Just doing up the transom and adding the bracket leads to increased point loads on the hull that need to be dealt with. Strength needs to be added which can be achieved in a variety of ways. The horsepower of today's modern outboards can be mind boggling when adding a five foot lever to them!!
Thank you for sharing this knowledge guide. As you correctly pointed out, the height of the cavitation plate is more crucial than many boat owners are aware of, however it would be of value to your viewers to give a specific measurement as there is a rule of thumb that can differ when say comparing a deep V to a cat. It is also of interest that a slight bit of toe in specifically on cats can make a huge difference to the steering and performance of the boat. You can make this a whole separate discussion point with a panel of experts.
A few of the cat makers are mounting the outboards so they lean in just a few degrees now. Hammercat is one and I _think_ Aquila does as well on the 36. I don't think Aspen does that with their proa design hulls.
A lot of good info in the episode. My old boat used to porpoise awful if you had any weight in back of the boat and tried to trim. But my new boat is pretty good.
You asked if we ever dealt with any of these issues: I have a 1984 186 Chris Craft Scorpion Bow Rider with 3.8 OMC Stringer Drive. The engine stringers rotted out so I had to rebuild them. In the process the engine height got too low in the back causing the cavitation plate t have water flowing over it. I have not totally fixed this issue yet because the boat lost 4 MPH off the top end but rides better because to hull does not pound in the Lake Michigan chop. We bought the boat when I was 25 and liked the speed. Now that I am 57 I like the more comfortable ride.
Years ago my brother and I had a '17 boat that had a severe "hook" in the back right in front of the transom (unknown to us at the time). It was a fixer upper that we had to piece together. We put a 115 on the boat and when when we took her out for the 1st time, it came out of the water just fine and as we increased speed the only part of the boat in contact with the water was the back of the boat. At full throttle, the area in front of the hook came out of the water and the only thing left in contact with the water was the motor & transom! All of a sudden the boat just went sideways! we thought we hit something! We tried it again with the same result. Later we saw the hook (caused by a 4 x 4 it was sitting on for years). We put a 55 on the back and never had that problem again!
I have seen this on a couple of seacrafts that had enclosed the transoms and bracket installed. The floatation on the bracket wasn’t enough to counteract the weight of two 4-strokes. Without trim tabs the boat would bounce.
I’ve fought with mine for over a year , it’s a left hand motor , changed transom height , had cup added to prop , changed prop , moved transducers , added a true tracker , it’s better but not perfect , I’ll be down there second week of august you wanna look at it
My last boat was a 23 Donzi with a bracket. I always had to keep the engine tucked all the way in and the trim tabs were always at least half deployed to keep the bow down. My new boat is a stepped hull 30 foot intrepid with an integrated bracket. That thing rides so flat with no trim tabs.
Super helpful! 🔥🔥🔥 so How you fix the extra weight changing from 2 stroke 200 to a 4 stroke 275 verado in a 22 sea pro. I only have the Porpoise effect on choppy water. Is there a way to fix it?? Or The only solution would be put a lighter motor again?, Thanks
Well I do have problems with porpoising on a brand new purchase in 2019. Nautic-Star 195 bay boat with 115HP Yamaha. I asked the dealer to supply it with a jack plate to enable me the option of flats fishing. The Atlas micro-plate supplied by them I believe is too small although it is rated for up to 115HP. It only raises the engine vertically about 3"-4", which does not raise it high enough to scoot over shallow flats. As well, when I tried trimming the motor out of the water for the first time, the steering hydraulic fittings hit the transom and broke off, leaving me no steering. Their fix was to put a mercury level limiter in the motor to stop the motor trimming up too far. That's useless, because now I can't trim the prop out for flushing salt water or even higher than bottom of hull to drift over shallows or use my electric motor over shallows. The lower unit keeps catching in the sand. But the big problem is porpoising. I have to keep the motor trimmed almost all the way down so it plows. Soon as I get it on plane with a slight trim up, well, splishy splashy starts. If there is the slightest breeze or chop, well I'm as wet as if I'd just taken a dip. Stumped as to what is my next course of action. Dealer's only answer is it's unfortunate and that the jack plate is rated for up to 115 hp Should I discard the jack plate idea? Or go with a bigger one that offsets the engine further from the transom?? Both would allow the removal of the trim limiter switch. But then I have to forget about flats fishing in Florida. And is the positioning of the jack plate causing the porpoising?
The first time I set up an outboard by myself I mounted it too low, confusing the anti-ventilation strake for one of the smaller strakes mounted higher on the lower unit, and ended up with a boat that reached for the moon before getting on plane and then would shovel water over the transom because of flow up the outboard housing. Thankfully, I had used to the top mounting hole from each of the bracket sections on my Mercury and was able to remount to the correct height without having to redrill.
I have those trim tab pocket vents on my Grady Marlin. When your fishing at the stern of the boat and she is rolling you here a woosh sound. Every first timer I take out in my boat always asks what’s that sound!!!
I had to add the vent hoses to a custom bracket on my boat. They worked perfectly. It’s many hundreds of pounds of water that gets stuck back there and (without vents) really holds the stern down in the water.
I also hve my front skier design from yrs back NOW for harbor patrol bouncing at limit power wt & conditions. This front skier acts as counter shocks working opposite wave bouncing action. Meaning if boat jumping in & out of water a tee pee won't work bc it needs to b right sized normal travel in the water to work. Tee pee holds u down but waves & speed jumping u means u need front skier help. The race boat tunnel but upside down is extreme design case, where u r flying at limit of being called boat & need dead water wt or u need wings bc u r going to take off 100 mph + crazy fast unless on glass waves.
Hello guys, congratulations for the video I am Italian and I always follow you. I did the same job on my boat by mounting a Bracket, I would like to know the starting point for the installation of a 225 mercury. From the video I understood that the starting point is the water intake at the same level as the keel. Right?
I also added a bracket to my 23 mako. I read online that the cavitation plate is to be raised 1 inch for every 10 inches of setback for your bracket. Common brackets are 30 inches so the motor needs to be raised 3 inches. I have 24 inch bracket and raised 2 inches. Havent been in the water yet but I hope it works.. Hope this helps.
Another great video but it raises a question for me. When you add a bracket how do you then determine proper engine height ? I don't think the straight edge along the hull method applies anymore and trial and error is very time consuming.
All things being equal, on a 17 ft aluminum boat that has a tendency to porpoise, would it get better or worse by adding a small set-back plate? My original thought was that it would improve. If the pivot point is the transom pad, then the engine would now be further back and have an easier time of keeping the bow up. Yes or no?? By the way, great video as always....
Those Evincrudes and Johnson Looper 6s were such good motors. Thirsty, but always brought you home. You could turn a 225 into a 250 with some jets and a powerpack too. I used to call mine Smokey Joe. Good times.
Hi , yes my question was about the poked holes on the transom for trim taps on old boats like the venture boat you mentioned, mine is a Aquasport with euro transom , what a diferente has you experienced after trough hole installed??
Hey, yes, night and day, it was a great fix for that boat, no more planning issues or having the back end of the boat sucked down in the water and bow rising. It worked great! Not sure if the Aquasport has the similar transom, but look at some pictures of a 1999 34 Venture and then your Aquasport and see how similar the back is
I would have liked to learn more about the reasons the “hook” (I’ve already forgotten the other term for the opposite deflection) developers in a fiberglass hull. Thank you.
I will like to know your opinion on a boat with factory platform like a aquasport 225cc 1999 that have a platform that is 4 in recede from the bottom and a boat with same factory platform but not recessed just a bottom all the way straight to the back
I have a 2008 Key West 1720 Pro. I have porpoising at top end without trim and I believe it is a result of low engine height as my straight edge like one in the video shows water coming over the antiventilation plate. I have also read some comments via a google search that indicate the same. I plan to move the engine up one hole as others have said this cured their problem
The more the spay of the front tee pee blades also is a factor. The more straight on the blades the faster but the more splayed the tee pee the more control against lift or yaw as well, again a computer nerd can work out the ideal range for said length w/ xy wt & how high bow sitting out of the water speed is the wild card. At limit performance U need an upside down opening arch on bottom & flat on top, so water rushing threw keeps boat attached & sitting on smooth water.
It is not my intention to critic anything you said, however if I remember correctly from my naval architecture course at the Naval Academy some 30 years back, the porpoising effect is not caused that much by the extra weight on the back, but by the extra length added to the boat. Generally, the length of a boat is considered in relation with the average wave length or the average time laps between a succession of waves and calculated so the bow and the stern will always sit on top of the waves. As I said, this is from a course taken some 30 years ago and my recollection may not be that sharp, so take it with a grain of salt.
I know brackets are widely used but I'd be really nervous about fitting one to a hull without speaking either to the designer of the hull, or to someone who has a good understanding of the particular hull.
So I have a 22’ Cameraman with heavy Honda 115s. Under certain conditions like being in calm water the boat will porpoise like crazy! I added Bob’s plates that did nothing. I’m wondering if my motors are to far down???
Do you raise or lower an engine if it is porpoising at high speeds and you have barely applied trim? Max trim is 5 and getting porpoise at 2.25 and 50 mph?
Maybe you have time to answer this question: I have a 1996 Maxum 17.5 outboard, rated for 125 hp but it has a 135 hp Black Max on it, so probably a bit heavy. It planes ok at maximum trim but I cannot trim up at all without porpoising. Is this a weight distribution problem or could it be something else? Basically I only have 2 useful trim settings, water and trailer, even though there is a trim gauge giving me a range of settings and it is a 2 speed trim so designed for micro adjustment on the bottom 1/4.
@@BornAgainBoating hi body you have so a nice videos, yes my question was about the trim taps poked holes that you mentioned on this video, I have a 225 aquasport euro transom, you mentioned that it can work as a vent and boat can has difficult to plane, what a diferente have you see after through holes installed????
lets start an experimental design... a center console with the outboard under the center console... a conventional shallow V hull in front of the engine and a twin hull behind it.. allowing a far better weight distribution and 360 degree fishing access .. a bellows around the base of the powerhead to keep splash from coming up around the outboard..
What i learned in boating school is....(a spongebob line there) 🤣🤣, sorry but serious what i picked up from this weeks video is that we should leave the bracket instalation to the profesionals
my boat is always throwing water up i beleieve its because of my motor being to low i plan to check now after watching this but i do not have electric trim i use the holes.
hving a piece of pipe cut in 1/2 or 1/3rd under the prop & trailing prop out the rear by 10" or so will improve performance. Better to use PVC bc very soft so won't hurt the prop, & rapping it in fiber or carbon glass for strength. If prop is 6" then u need health bigger width pipe so won't chance hitting it. A teeter tooter effect so 35 vs 65% length or so length of pipe running long out the back. The front end of pipe can b round but back end prop on needs to b cut gone. The pipe can then naturally teeter up & down but not hit the prop.
I have a 14’ vhull John boat. Had a 2 stroke 5hp on it. Just bought a Suzuki 9.9hp. I notice the engine is a lot heavier the w it ventilation plate is to low now. 😢. It looks like proper height out of water but in the water it heavier so it sinks the boat in water causing it to be to low and it’s dragging. So I think I need a jack plate now. Any suggestions? And not just a heart lol
Thanks for the tips, I am watching many of your videos as I am hoping to refit my 26’ searay with an outboard, if you can recommend a bracket or where to get a good used one please let me know! Or if you want the job of doing it shoot me a price, I’m a Borne again Marine Corps challenged veteran (i have the word disabled because God makes everything able)!!
powerful torque props( need computer modeling to max dial in) can hve sharp cutting edge then hve 2, or 3 separate thin sheet twist diff blades. So wt is jack light but leading edge is stronger if it hits anything+^! hving diff cut bit angles & length of blades in 2 n1 or 3n1 if bigger means far more efficient prop design. 3 blade if really 4 or 5 separate twisting blades of prop & jack little extra wt. Diff between polished or serrated knife better design home run! Leading prop may b 2 blade that cuts 4 ways is best but trailing 3 blades makes 4 or 5 cuts might b best. Swallow leading angle front cut pull then opposite trailing prop. Computer design & real world testing & modeling will be sure.
I also hve a spear pnt nose water tight hull design only smaller & longer & thinner than bulb bc want to keep boat in water by spear front end & tee pee.
the top wing over prop needs to hve screen like holes cheese in it. So air can get out but water goes drive by. I think a 1/2 holes side & 1/2 solid wing over prop is best but speed of prop spin matters greatly.
The ‘plate’ on the motor is a cavitation plate, not an anti ventilation plate! Ventilation & cavitation are two different problems! Sorry but when did all these new terms for outboards start coming about? ‘Leg’ for the mid-section, ‘foot’ for the lower unit etc etc. Over 40 years in the outboard business here. If you don’t know what it is look it up!!!
u need a tee pee keel setup on these tiny shit boats running at speed, that tighten back into normal keel blade as it head front to back. It is all about the wt of water pushing down on duel tee pee front blades & how far b4 transitioning back n2 single blade till u fades down to nothing, & the length of the tee pee. If front of boat runs 3 or 4ft out of water then tee pee needs 18" more still in the water up front some where, esp if tiny shit boat. some computer nerd can work out the formula but that is the deal.
This channel is so underrated..
Forreal.
Very much so. To the point and crazy good information
The through hull fittings installed to break the vacuum in the trim tab pockets was a slick idea. I love this channel because it’s chock full of slick tips like that!
Never had this problem. Always knew that the engine needed to be set just right. Always had someone like you to make sure that it was done right. Great information always a pleasure to see what you are doing. 👍😎🌴 Stay safe out there.
I really enjoy your clear matter of fact style. Ive watched you and been subscribed for many month's. I live on Casco Bay in South Portland Maine. My 1998 Honda bf90 threw a connecting rod through the crankcase cover last November. But it never died as I watched its oil pump out it still idled me a mile or more to the ramp...I had no choice.
My wife and I traveled to Marathon last month and stayed at the Jolly Roger RV park. I was so surprised to see your channel say that week I was so close to your Marina. On the way to Coco plum Beach I stopped in to say hi and see what you might have to replace my beloved Honda but you were closed 2 times I came by.
Anyway I like your shows! Very clear! Thanks very much.
In my experience, a hard overhead roof or soft Bimini top can also contribute to the porpoising, especially if cruising into the wind and waves. One of the many reasons that I love boating, the frequent adjusting to the conditions. Thanks for another great tutorial.
Don't know how I missed this episode. Great information. My Simmons Sea Skiff has a hook on purpose. Originally I had a 70HP Tohatsu that had issues. I didn't trust a 2stroke. I repowered her with a Suzuki 60. I learned about weight distribution and she don't Porpoise no more. Alleluia. Great info, thanks
The porpoising typically happens inside of a speed range and under certain load conditions. For instance we have a pretty fast twin engine boat with a bracket which tops out well over 70mph, but under light load conditions it nearly always porpoises between 45-50mph. This is the speed range in which it begins to lift the hull out of the water and outside of that speed range it runs perfect, but inside that speed range it's unstable. Adding a few passengers to the front of the boat moves the speed range up by maybe 5mph etc. What we have is an old school "straight hull" and it's fun because you can vary the angle of attack a lot with the trim, it runs great you just have to know how to drive it. I guess the modern solution to all this is to add steps and then boat will have the same angle of attack almost not matter what you do with the trim, and no porpoising. But honestly I like my old school hull, it's fun to play with the trim and it's as fast as anything once you trim her up and open her up. But basically if have porpoising problems start with moving the weight around, you're either going to want to make the nose heavier or lighter and then play with the trim. Offshore the easy solution is typically to add more weight in the front.. but it's going to run wet. Probably.
MATHS are hard. That is why I prefer hillbilly math.....but also probably explains why my last two boats are at the bottom of the lake! Thanks for posting!!!!
Love this!
Wow...never knew that about the tab pockets....you are a master of your craft sir
Thanks guys for your content, Yes I've experienced porpoising effect, my father years ago built a bondwood boat, cabin cruiser 20foot and he decided to increase the cabin size by lengthening the aft (of the cabin not the hull) one foot. This stuffed up the balance of the boat, hence fuel and water tanks forward extra anchor chain and a refit to the cabin layout. It was a nightmare and lesson learned.
I remember the good ole days. I didn’t have to worry about brackets , trim tab pockets , four stroke motors , they didn’t exist. Trim / tilt was advanced !
Súper helpful this video I learn something new today,those hole in the back are made it to release air and let the boat get on plain faster, interesting 🤨 thanks for the video 👍
Great information. One of the best channels on UA-cam. Always learning something new on a Tuesday!
Great to hear!
This was the most excellent simi technical explanation of hydro physics real life functions I have ever heard concerning this modification. I have been considering a repower on my 77 SeaRay 24ft sedanbridge.
Not all 'hooks' are due to age changes on boats. In the seventies and eighties on up there were boats which used the 'hook' to achieve level plane with minimum horsepower. This was emphasized after the seventies oil embargo when low horsepower boats were in demand and continued on for many years. I have also had porpoising from boats that were designed to be used with inboard power as well as I/O and outboards. They incorporated a full keel which went 3/4 of the way aft and would have been used for the shaft of an inboard. At higher speeds (27-8 knots and above) the partial keel wanted to be a planing surface but wasn't large enough to maintain so the effect was porpoising. Trim tabs helped on some but bottom line was that type of hull just had a built in speed limit. A lot of forces are increased dramatically on the hull that has been swapped over to a bracket. Just doing up the transom and adding the bracket leads to increased point loads on the hull that need to be dealt with. Strength needs to be added which can be achieved in a variety of ways. The horsepower of today's modern outboards can be mind boggling when adding a five foot lever to them!!
I would really like to work with u.... and never end learning...
Thank you for sharing this knowledge guide. As you correctly pointed out, the height of the cavitation plate is more crucial than many boat owners are aware of, however it would be of value to your viewers to give a specific measurement as there is a rule of thumb that can differ when say comparing a deep V to a cat. It is also of interest that a slight bit of toe in specifically on cats can make a huge difference to the steering and performance of the boat. You can make this a whole separate discussion point with a panel of experts.
A few of the cat makers are mounting the outboards so they lean in just a few degrees now. Hammercat is one and I _think_ Aquila does as well on the 36. I don't think Aspen does that with their proa design hulls.
A lot of good info in the episode. My old boat used to porpoise awful if you had any weight in back of the boat and tried to trim. But my new boat is pretty good.
You asked if we ever dealt with any of these issues: I have a 1984 186 Chris Craft Scorpion Bow Rider with 3.8 OMC Stringer Drive. The engine stringers rotted out so I had to rebuild them. In the process the engine height got too low in the back causing the cavitation plate t have water flowing over it. I have not totally fixed this issue yet because the boat lost 4 MPH off the top end but rides better because to hull does not pound in the Lake Michigan chop. We bought the boat when I was 25 and liked the speed. Now that I am 57 I like the more comfortable ride.
Years ago my brother and I had a '17 boat that had a severe "hook" in the back right in front of the transom (unknown to us at the time). It was a fixer upper that we had to piece together. We put a 115 on the boat and when when we took her out for the 1st time, it came out of the water just fine and as we increased speed the only part of the boat in contact with the water was the back of the boat. At full throttle, the area in front of the hook came out of the water and the only thing left in contact with the water was the motor & transom! All of a sudden the boat just went sideways! we thought we hit something! We tried it again with the same result. Later we saw the hook (caused by a 4 x 4 it was sitting on for years). We put a 55 on the back and never had that problem again!
I have seen this on a couple of seacrafts that had enclosed the transoms and bracket installed. The floatation on the bracket wasn’t enough to counteract the weight of two 4-strokes. Without trim tabs the boat would bounce.
Thank you, your videos are always so helpful and informative.
I’ve fought with mine for over a year , it’s a left hand motor , changed transom height , had cup added to prop , changed prop , moved transducers , added a true tracker , it’s better but not perfect , I’ll be down there second week of august you wanna look at it
wow I just through repowering a old boat was just about making sure the transom strong enough and the engine height was correct.
My last boat was a 23 Donzi with a bracket. I always had to keep the engine tucked all the way in and the trim tabs were always at least half deployed to keep the bow down. My new boat is a stepped hull 30 foot intrepid with an integrated bracket. That thing rides so flat with no trim tabs.
Only have seen a few donzi boats and I have loved them!
Super helpful! 🔥🔥🔥 so How you fix the extra weight changing from 2 stroke 200 to a 4 stroke 275 verado in a 22 sea pro. I only have the Porpoise effect on choppy water.
Is there a way to fix it?? Or The only solution would be put a lighter motor again?, Thanks
So note to self... bring straight edge when boat shopping used boats to check for hooks inches hull
Right i would have never guessed hulls could settle like that
You can also add flotation as part of the bracket to help with additional weight.
Thank you! You've just saved me thousands of dollars on my planing issues with my 27 Whaler, by adding the vent in the trim tab pockets!
Hi sr I have an Aquasport 225 with trim taps pockets, what a different it make to you to add the vents???
Hi sr , what a diferente it makes to you t adding the vetns on trim pockets???
Well I do have problems with porpoising on a brand new purchase in 2019. Nautic-Star 195 bay boat with 115HP Yamaha. I asked the dealer to supply it with a jack plate to enable me the option of flats fishing. The Atlas micro-plate supplied by them I believe is too small although it is rated for up to 115HP. It only raises the engine vertically about 3"-4", which does not raise it high enough to scoot over shallow flats. As well, when I tried trimming the motor out of the water for the first time, the steering hydraulic fittings hit the transom and broke off, leaving me no steering. Their fix was to put a mercury level limiter in the motor to stop the motor trimming up too far. That's useless, because now I can't trim the prop out for flushing salt water or even higher than bottom of hull to drift over shallows or use my electric motor over shallows. The lower unit keeps catching in the sand. But the big problem is porpoising. I have to keep the motor trimmed almost all the way down so it plows. Soon as I get it on plane with a slight trim up, well, splishy splashy starts. If there is the slightest breeze or chop, well I'm as wet as if I'd just taken a dip. Stumped as to what is my next course of action. Dealer's only answer is it's unfortunate and that the jack plate is rated for up to 115 hp
Should I discard the jack plate idea? Or go with a bigger one that offsets the engine further from the transom?? Both would allow the removal of the trim limiter switch. But then I have to forget about flats fishing in Florida. And is the positioning of the jack plate causing the porpoising?
You guys are so awesome and an inspiration to our channel! Your videos have kept my boat running!
The first time I set up an outboard by myself I mounted it too low, confusing the anti-ventilation strake for one of the smaller strakes mounted higher on the lower unit, and ended up with a boat that reached for the moon before getting on plane and then would shovel water over the transom because of flow up the outboard housing. Thankfully, I had used to the top mounting hole from each of the bracket sections on my Mercury and was able to remount to the correct height without having to redrill.
I have those trim tab pocket vents on my Grady Marlin. When your fishing at the stern of the boat and she is rolling you here a woosh sound. Every first timer I take out in my boat always asks what’s that sound!!!
Expert level knowledge here
2 stroke for as long as I can find parts
2-stroke gang!
I had to add the vent hoses to a custom bracket on my boat. They worked perfectly. It’s many hundreds of pounds of water that gets stuck back there and (without vents) really holds the stern down in the water.
How do you installed vent hose on a custom bracket ??? Please let me know, some pictures will help
I also hve my front skier design from yrs back NOW for harbor patrol bouncing at limit power wt & conditions. This front skier acts as counter shocks working opposite wave bouncing action. Meaning if boat jumping in & out of water a tee pee won't work bc it needs to b right sized normal travel in the water to work. Tee pee holds u down but waves & speed jumping u means u need front skier help. The race boat tunnel but upside down is extreme design case, where u r flying at limit of being called boat & need dead water wt or u need wings bc u r going to take off 100 mph + crazy fast unless on glass waves.
Hello guys,
congratulations for the video I am Italian and I always follow you. I did the same job on my boat by mounting a Bracket, I would like to know the starting point for the installation of a 225 mercury. From the video I understood that the starting point is the water intake at the same level as the keel. Right?
I also added a bracket to my 23 mako. I read online that the cavitation plate is to be raised 1 inch for every 10 inches of setback for your bracket. Common brackets are 30 inches so the motor needs to be raised 3 inches. I have 24 inch bracket and raised 2 inches. Havent been in the water yet but I hope it works.. Hope this helps.
bayliner has no problems. bought perfectly tip top shape
thanks, great video, keep posting more about height of motor on transom
Soooo I shouldn’t put a swim platform in my ‘78 Glastron 213?
I was planning on adding a swim platform and keeping the low cut transom.
Another great video but it raises a question for me. When you add a bracket how do you then determine proper engine height ? I don't think the straight edge along the hull method applies anymore and trial and error is very time consuming.
All things being equal, on a 17 ft aluminum boat that has a tendency to porpoise, would it get better or worse by adding a small set-back plate? My original thought was that it would improve. If the pivot point is the transom pad, then the engine would now be further back and have an easier time of keeping the bow up. Yes or no?? By the way, great video as always....
Those Evincrudes and Johnson Looper 6s were such good motors. Thirsty, but always brought you home. You could turn a 225 into a 250 with some jets and a powerpack too. I used to call mine Smokey Joe. Good times.
Hi , yes my question was about the poked holes on the transom for trim taps on old boats like the venture boat you mentioned, mine is a Aquasport with euro transom , what a diferente has you experienced after trough hole installed??
Hey, yes, night and day, it was a great fix for that boat, no more planning issues or having the back end of the boat sucked down in the water and bow rising. It worked great! Not sure if the Aquasport has the similar transom, but look at some pictures of a 1999 34 Venture and then your Aquasport and see how similar the back is
@@BornAgainBoating hi man thanks for the response 👍, yes aquasport used the same transom design and I always has that problem trying to get on plane.
I would have liked to learn more about the reasons the “hook” (I’ve already forgotten the other term for the opposite deflection) developers in a fiberglass hull. Thank you.
My Dusky has hooks on both sides. Don’t know if it’s a defect or it was made like this from factory. Any Ideas
I will like to know your opinion on a boat with factory platform like a aquasport 225cc 1999 that have a platform that is 4 in recede from the bottom and a boat with same factory platform but not recessed just a bottom all the way straight to the back
I have a 2008 Key West 1720 Pro. I have porpoising at top end without trim and I believe it is a result of low engine height as my straight edge like one in the video shows water coming over the antiventilation plate. I have also read some comments via a google search that indicate the same. I plan to move the engine up one hole as others have said this cured their problem
I just want to move it up, any suggestions to prevent problems would be appreciated. Thanks
The more the spay of the front tee pee blades also is a factor. The more straight on the blades the faster but the more splayed the tee pee the more control against lift or yaw as well, again a computer nerd can work out the ideal range for said length w/ xy wt & how high bow sitting out of the water speed is the wild card. At limit performance U need an upside down opening arch on bottom & flat on top, so water rushing threw keeps boat attached & sitting on smooth water.
It is not my intention to critic anything you said, however if I remember correctly from my naval architecture course at the Naval Academy some 30 years back, the porpoising effect is not caused that much by the extra weight on the back, but by the extra length added to the boat. Generally, the length of a boat is considered in relation with the average wave length or the average time laps between a succession of waves and calculated so the bow and the stern will always sit on top of the waves. As I said, this is from a course taken some 30 years ago and my recollection may not be that sharp, so take it with a grain of salt.
I have a little 16' cabin boat that porpoises like crazy when there is too much weight at the stern. When it starts, I have to move everyone forward.
Learned a couple things from this video. Thanks!
Armstrong brackets add floatation to counter the weight, right?
I know brackets are widely used but I'd be really nervous about fitting one to a hull without speaking either to the designer of the hull, or to someone who has a good understanding of the particular hull.
How do you fix a deformed hull ? Go off shore , call the coasties and scuttle it when you see the helicopter
So much to think about while boating. Thanks for the content.
You bet!
Where you guys at? Can you install one of those on my 91 Grady white ?
So I have a 22’ Cameraman with heavy Honda 115s. Under certain conditions like being in calm water the boat will porpoise like crazy! I added Bob’s plates that did nothing. I’m wondering if my motors are to far down???
Awesome videos as always! Thanks for the content.
Do you raise or lower an engine if it is porpoising at high speeds and you have barely applied trim? Max trim is 5 and getting porpoise at 2.25 and 50 mph?
I love your channel. Thanx for all the great info. I would like to see more on 2020 40hp to 60hp mercury services though cause thats what i have lol.
Maybe you have time to answer this question: I have a 1996 Maxum 17.5 outboard, rated for 125 hp but it has a 135 hp Black Max on it, so probably a bit heavy. It planes ok at maximum trim but I cannot trim up at all without porpoising. Is this a weight distribution problem or could it be something else? Basically I only have 2 useful trim settings, water and trailer, even though there is a trim gauge giving me a range of settings and it is a 2 speed trim so designed for micro adjustment on the bottom 1/4.
How much of a issue the poked holes are on a platform?? Aquasport 225 , has you see a good difference after trough hull installed??
Sorry but I'm not sure what you are asking :/
@@BornAgainBoating hi body you have so a nice videos, yes my question was about the trim taps poked holes that you mentioned on this video, I have a 225 aquasport euro transom, you mentioned that it can work as a vent and boat can has difficult to plane, what a diferente have you see after through holes installed????
Hi, I have the poked holes on my platform,( aquasport 225) is this a real issue??
Best thing I put on my boat to fix it was a cheap set of auto trim tabs.
Is it normal to have lots of water splash up from between the hull and the engine?
lets start an experimental design... a center console with the outboard under the center console... a conventional shallow V hull in front of the engine and a twin hull behind it.. allowing a far better weight distribution and 360 degree fishing access .. a bellows around the base of the powerhead to keep splash from coming up around the outboard..
What i learned in boating school is....(a spongebob line there) 🤣🤣, sorry but serious what i picked up from this weeks video is that we should leave the bracket instalation to the profesionals
my boat is always throwing water up i beleieve its because of my motor being to low i plan to check now after watching this but i do not have electric trim i use the holes.
hving a piece of pipe cut in 1/2 or 1/3rd under the prop & trailing prop out the rear by 10" or so will improve performance. Better to use PVC bc very soft so won't hurt the prop, & rapping it in fiber or carbon glass for strength. If prop is 6" then u need health bigger width pipe so won't chance hitting it. A teeter tooter effect so 35 vs 65% length or so length of pipe running long out the back. The front end of pipe can b round but back end prop on needs to b cut gone. The pipe can then naturally teeter up & down but not hit the prop.
Hi can I send you photos can you help with speed new motor new boat but speed is problem.thanks
I have a 14’ vhull John boat. Had a 2 stroke 5hp on it. Just bought a Suzuki 9.9hp. I notice the engine is a lot heavier the w it ventilation plate is to low now. 😢. It looks like proper height out of water but in the water it heavier so it sinks the boat in water causing it to be to low and it’s dragging. So I think I need a jack plate now. Any suggestions? And not just a heart lol
LOL! I’ll take the heart!
How to calculate how high to motor motors?
Porpoising to me is a good thing add tabs to stabilize and its performance is peak
Thanks for the tips, I am watching many of your videos as I am hoping to refit my 26’ searay with an outboard, if you can recommend a bracket or where to get a good used one please let me know! Or if you want the job of doing it shoot me a price, I’m a Borne again Marine Corps challenged veteran (i have the word disabled because God makes everything able)!!
Great information... thank you!
Glad it was helpful!
Doesnt the bracket or pod add to the floatation like a float tank?
What marina do you work out of?
Great content mate 💯👌
Thanks for the visit
powerful torque props( need computer modeling to max dial in) can hve sharp cutting edge then hve 2, or 3 separate thin sheet twist diff blades. So wt is jack light but leading edge is stronger if it hits anything+^! hving diff cut bit angles & length of blades in 2 n1 or 3n1 if bigger means far more efficient prop design. 3 blade if really 4 or 5 separate twisting blades of prop & jack little extra wt. Diff between polished or serrated knife better design home run! Leading prop may b 2 blade that cuts 4 ways is best but trailing 3 blades makes 4 or 5 cuts might b best. Swallow leading angle front cut pull then opposite trailing prop. Computer design & real world testing & modeling will be sure.
Great information.
Thanks for watching!
I also hve a spear pnt nose water tight hull design only smaller & longer & thinner than bulb bc want to keep boat in water by spear front end & tee pee.
Out of water much & u need a skier bc spear & tee pee can't work unless in the water.
Have you ever seen cuban rafts floating over while you're out in the water?
the top wing over prop needs to hve screen like holes cheese in it. So air can get out but water goes drive by. I think a 1/2 holes side & 1/2 solid wing over prop is best but speed of prop spin matters greatly.
There's something about those set ups I don't like. They must create drag on the boat .
The ‘plate’ on the motor is a cavitation plate, not an anti ventilation plate! Ventilation & cavitation are two different problems! Sorry but when did all these new terms for outboards start coming about? ‘Leg’ for the mid-section, ‘foot’ for the lower unit etc etc. Over 40 years in the outboard business here. If you don’t know what it is look it up!!!
Dang this is super educational
Thanks You.
If this boats a rocking... it's probably a trim issue
Brilliant
Very Interseting
nice
Oh porpoising like every mako lol
💯
u need a tee pee keel setup on these tiny shit boats running at speed, that tighten back into normal keel blade as it head front to back. It is all about the wt of water pushing down on duel tee pee front blades & how far b4 transitioning back n2 single blade till u fades down to nothing, & the length of the tee pee. If front of boat runs 3 or 4ft out of water then tee pee needs 18" more still in the water up front some where, esp if tiny shit boat. some computer nerd can work out the formula but that is the deal.
Just apply common sense to boating and you will have a trouble free day on the water.
Good day, I sent an email to your address.
Brackets...👎👎 ugh
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Great information.
Thanks for watching!