The Magic of Underwater Exhaust in Custom Sportfish Boats at Jarrett Bay - JB Insider: Ep. 1
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- Опубліковано 29 січ 2020
- Jarrett Bay Insider Episode 1 takes an in-depth look at how a Jarrett Bay boat covertly routes and cools engine exhaust underwater. Plus, we also visit the service high bay to discuss anti-fouling coatings for running gear and boat bottoms.
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Ray Hodge does an excellent job presenting the Insider series.Keep them coming.
Man I love seeing you guys on UA-cam. Thank you
Nothing but net, that’s some fine engineering right there.
I have to say that this series has literally changed my focus from Viking to Jarrett Bay. Outstanding pieces, well produced and edited. Great information and clear differentiation from mass production without passion. Others are good, this is awesome.
Full custom vs not… I mean who would ever buy a Viking over a JB
RV, love this content and insight, especially for the daily boater who dreams of a ride like this one 😎
Woww man , amazing engineering. Good job man 👍👍
wow nice to see you again!!! Happy New Year!
Great explanation.
awesome channel
Mario Amarti of Itama fame was the first to use UW exhausts back in the 80s / 90 s
Love it
How at idle or if the engines at drift with engines off do you stop water from coming up the exhaust into the engine?
Hi RV. Has it been considered to integrate a flapper valve/gate within the doghouse or within an exhaust tube to avoid sea water backflow when backing down on a fish?
Just a thought what if you but the exaust in the middle of the boat, so the haul got a "aircussion" so to speak. less drag?
Whats keeps water from going back to the engine when engine is not running?
if i win the lotto, im calling you guys.
question -- the underwater exhaust exits, it looks like, where the trim tab pocket would normally be. So does that exhaust style require the switch to interceptor style trim tabs? and those tabs moved more towards the centerline?
Good observation.
In the past we have used conventional trim tabs, squeezed inboard, with the underwater exhaust system. However, once the Interceptor/Humphree trim tabs entered our world, all of our customers have opted for them. Both trim systems create an overcrowding issue, but, as with everything in custom boat building, we just have to figure it out and make it work. That’s probably what attracts a lot of us into this business.
In the video at 3:11 there is a brief glimpse of the starboard side recess pocket for the Humphree trim tab on Hull 64.
Good question. Thank you for your interest. - RV
@@JarrettBay thanks for the response, RV! Also, I'm guessing that putting the Humphree on the stern, surface mount, above where the exhaust exits wouldn't work because the exhaust would essentially punch a hole in the water just forward of the tab. Negating any effect the tab might have.
@@JarrettBay moving your tabs inboard exponentially reduces their effectiveness. Agreed? Been building boats my whole life here in wanchese and have seen many fads come and go..
Hi Michael, That is a good point. Any changes to the hull of a boat can have a negative effect on some other aspect of performance. So far, our designers have been able to maintain trim functionality with it squeezed inboard due to the underwater exhaust. That is one of the concerns when designing around an underwater exhaust.
Hi RV. Can you advise on underwater exhaust but exiting the hull just behind the engines in the engine rooms, instead of out the transom?
Sort of where you have the dog house but out the bottom right there.
What are your thoughts or experience in this scenario?
Thank you
Alex
I have seen some boats with the exhaust in the configuration that you have described. And it certainly looks tempting for the space savings that would be available.
However, I have no first-hand experience with that, and, to my knowledge, Jarrett Bay hasn’t installed one. That said, I can’t speak with any real authority on the subject. If I was considering it on a project, I would want a few answers before I broke out the Sawzall. I’m sure there are more pitfalls to consider, but offhand these three questions immediately pop into my head.
First, what is the potential of exhaust coming up beside the boat (smudging up the hull) and possibly back drafting into the cockpit?
Second is how would the exhaust backpressure be affected?
And Third is how would the back down “surge” inside the exhaust chamber be absorbed?
I would take those questions up with the engine manufacturer and an exhaust designer before I went to the next step.
@@JarrettBay excellent reply. I do appreciate the honest feedback. Definitely some unknowns here that would require further assessment before committing.
Thank you, Alex
So, what you didn’t cover in the video is that style of exhaust needs a bypass. A bypass is a smaller usually 2” or possibly even smaller but on this boat more like a 4”, exhaust tube that goes out the back of the boat. That way when the boats sitting still, running, it does not create a splash on the side of the boat.
So the entire exhaust system fills with water when the vessel not under power?
Maybe has a big ass scupper
Only what's below the waterline. Duh.
How do you guys/other builders deal with the added back pressure those underwater exhausts produce towards the engine? I can see how it might not have as big of an affect while running but what about when the boat is sat still? I'm no professional on this, just have a feeling that the added pack pressure would result in loss of performance??
Good question! In short, there is an engine idle bypass built into these systems. So at idle, the exhaust is routed to smaller outlets just above the waterline.
@@JarrettBay And then once the engine is up to speed, the air flow out of the engine negates the back pressure problem caused by water.
What is the brand of the insulation on the exhaust?
Chris - the exhausts were fabricated by Marine Exhaust Systems (marine-exhaust.com). The insulation is proprietary, developed in-house by them. If you reach out to them, Jason Frye with their company would be happy to answer any more questions you may have.
@@JarrettBay Excellent. Thanks for your response!
Underwater Exhaust! All marine life know you are there and the sea get more and more acidic.
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