Surf Pipes for Yamahas invented yet?

[Farny]

So with risk of CO poisoning - anyone invented an in water surf pipe yet?

 

[Cobra Jet Steering LLC]

We discussed it on this site several years ago but I guess not, It was also discussed to prevent the low side engine from not wanting to start due to excess back pressure on the exhaust system. https://jetboaters.net/threads/hard...llasted-ar240-wake-surfing.13897/#post-240613

 

[Farny]

We discussed it on this site several years ago but I guess not, It was also discussed to prevent the low side engine from not wanting to start due to excess back pressure on the exhaust system. https://jetboaters.net/threads/hard...llasted-ar240-wake-surfing.13897/#post-240613

Thanks for the reply. Wondering if back pressure causes n issue from exhaust outlet below water, why wouldn’t dedicated surf boats have that issue with their surf pipe?

 

[Farny]

Just found this - interesting he’s even taken a dual exhaust to a single pipe

https://www.freshairexhaust.com/videos/

I’ll post what they say at FAE

 

[ripler]

I would ask your dealer if it's safe to do especially if you are under warranty. When I bought my MasterCraft my dealer made sure to tell me that adding a FAE to my boat would void the engine warranty. He did also say that he did have customers add a FAE to their boats, but they removed them when bringing the boat for service. I would love to add a FAE for noise reduction behind the boat. I have a 6.0L V8 that has zero exhaust noise reduction, I have to admit it does sound badass though.

 

[Cobra Jet Steering LLC]

That pipe is designed to create a vacuum and pull the exhaust out of the pipe using the water it is moving through to create a suction, as for jet boats they have the exhaust going out sideways aimed at the center of the boat in the pump opening not at the water behind the boat like prop boats do. The lower the side the more pressure on the exhaust system when not running and when people tried starting the top engine first and getting the boat moving before starting the lower engine it seemed to work fine convincing me that the increase in back pressure was the issue, different setups different engines I just looked at the lower engines not starting and the issue was common , as for wake surfing each year it gets outlawed in more places some countries have outlawed it totally so I would imagine coming up with a solution would be a good thing to deal with the poising issues at least.

 

[ripler]

The other thing I just thought of is that the FAE would need to be lower than the hull to put the exhaust fumes into the water which totally negates the jetboat advantage.

 

[84rzv500r]

I think the water box volume + exhaust piping volume should be enough to allow for starting normally.... this is QED... why not use some stainless OVAL or aluminum airfoil tubing as the space between the exhaust outlets is limited and extend them down to ensure below water on plane... a simple bolt on transition could be fabbed.... Im aware of the hydrostatic equation P' = P + pgh but were talking a really small h here... and you could angle/shape the tip to create vacuum to aid in extraction ???

 

[84rzv500r]

The other thing I just thought of is that the FAE would need to be lower than the hull to put the exhaust fumes into the water which totally negates the jetboat advantage.

Everything is generally a compromise... if properly positioned the keel will still be the lowest point however the tips would need to extend below the bottom of the boat but not the keel

 

[Farny]

Everything is generally a compromise... if properly positioned the keel will still be the lowest point however the tips would need to extend below the bottom of the boat but not the keel

That would be my assessment as well. Looking forward to hearing from free air exhaust with their ideas.

 

[Farny]

I would ask your dealer if it's safe to do especially if you are under warranty. When I bought my MasterCraft my dealer made sure to tell me that adding a FAE to my boat would void the engine warranty. He did also say that he did have customers add a FAE to their boats, but they removed them when bringing the boat for service. I would love to add a FAE for noise reduction behind the boat. I have a 6.0L V8 that has zero exhaust noise reduction, I have to admit it does sound badass though.

Yea I think a Yamaha engine expert is my second stop for research after seeing if FAE can even do anything with our setups.

 

[Farny]

Thought fit for a couple bends … may be too drastic to bring the exhaust straight back out of the transom & down

 

[84rzv500r]

yeah I grabbed a spare exhaust elbow and went out to my boat which is setting in it's bunk right now waiting for my lazy a$$ to reseal the jet tunnels and stick on some 15/22 dynaflys... its tight in my boat so that's why i mentioned oval tubing and going straight down... its tight on my boat and your boats are newer and the engines are set much closer together

 

[Farny]

yeah I grabbed a spare exhaust elbow and went out to my boat which is setting in it's bunk right now waiting for my lazy a$$ to reseal the jet tunnels and stick on some 15/22 dynaflys... its tight in my boat so that's why i mentioned oval tubing and going straight down... its tight on my boat and your boats are newer and the engines are set much closer together

What sealant are you using for the jet tunnel? That’s on my project list too!

 

[84rzv500r]

i use marine RTV silicone (not 4200or 5200 its too viscous for sealing the tunnels, i use it for through hulls) i did it three years ago and there are some spots that need touched up

 

[MidnightRider]

Surf pipes work by putting the exhaust output into the prop stream which force the exhaust back behind the surfer. I'm not sure it would work as well if you just put the exhaust into the water behind the boat. Not sure there would be a good way to get the exhaust into the jet stream on a jet boat.

 

[84rzv500r]

Surf pipes work by putting the exhaust output into the prop stream which force the exhaust back behind the surfer. I'm not sure it would work as well if you just put the exhaust into the water behind the boat. Not sure there would be a good way to get the exhaust into the jet stream on a jet boat.

prolly not as it's an action reaction kinda thing drive vs a mechanical screw kinda thing....

 

[Farny]

Surf pipes work by putting the exhaust output into the prop stream which force the exhaust back behind the surfer. I'm not sure it would work as well if you just put the exhaust into the water behind the boat. Not sure there would be a good way to get the exhaust into the jet stream on a jet boat.

Even if it just in the water - I am guessing better than right into the air. My guess it would still reduce CO to the surfer. FAE emailed me back and I sent transom pics etc. looking forward to seeing what they say

 

[kgower]

Even if it just in the water - I am guessing better than right into the air. My guess it would still reduce CO to the surfer. FAE emailed me back and I sent transom pics etc. looking forward to seeing what they say

Keep us posted.