buy 2020 or wait for 2021?

[K223]

I was thinking that perhaps boats tend to operate at more consistent RPMs? On the road, your consistently changing RPMs due to stops, passing, etc. It's why you have a gas pedal (and brake). On a boat, no gas pedal, as you'll shift RPMs much less frequently.

Being the turbos are a boost to be used only over short time periods (seconds) when you are specifically looking for acceleration, does it makes sense to have boost on a boat when the application doesn't lend it self to short time periods of acceleration?

Exactly. Marine engines are a bit different in operation as compared to land vehicles. However race boats and such I believe have employed forced induction methods.

Not to mention emissions standards for boats are different. I guess you can go on and on. Surely not apples to apples here.

 

[EricM]

I'd think that a turbo engine would actually perform better in a boat than a N/A engine, since, as you guys point it, it's under load more of the time and would essentially be in boost all of the time.

Lake water cooling for the boosted air, the exhaust manifolds, and the turbos. Seems to me to be a way better application for a smaller turbo engine than a big truck actually.

I'm guessing the added complexity of the turbo system, mainly- and additionally the piercing sound of a continuously spooled turbo (which would be very annoying to passengers sitting in a smaller boat where the engine isn't buried 5 feet below them) is why you don't see small boosted engines in boats.

There are supercharged jet skis and boats galore, so it's not an octane/boost thing necessarily.

 

[melvimbe]

I am far from an expert on this subject, but operating a vehicle in boost for long periods of time (minutes) would mean that you're increasing the pressure and heat in that engine for long periods of time, which would decrease the life of the engine?

I understand that aircraft will have turbo-normalization, but that's a different scenario. Instead of increasing the air above sea level atmospheric pressure, it's increasing the the thinner are at higher altitudes back to sea level atmospheric pressure.

But I think your point of system complexity also matters. You don't really want to deal with turbos and intercoolers on your pontoon.

 

[K223]

I am far from an expert on this subject, but operating a vehicle in boost for long periods of time (minutes) would mean that you're increasing the pressure and heat in that engine for long periods of time, which would decrease the life of the engine?

I understand that aircraft will have turbo-normalization, but that's a different scenario. Instead of increasing the air above sea level atmospheric pressure, it's increasing the the thinner are at higher altitudes back to sea level atmospheric pressure.

But I think your point of system complexity also matters. You don't really want to deal with turbos and intercoolers on your pontoon.

True, over complex systems for pleasure craft and fishing boats are just that, too complex and too many POF’s in time. The sea for one is a rough place to operate in. Again for speed and race boats it can be a different story. Air to water intercoolers would be very effective in this environment and surely bring down air temps much more efficiently than air to air IC’s.

Mercury for one does produce turbo diesels for smaller to mid sized boats. But what is a Diesel engine without a turbo.

@EricM opinion on making more power on the water with a forced induction engine is justified. But has more limited uses.

Years back I bought a set of BBC 990(if your familiar) ported and polished heads brand new off a gent. He was going to put them on a low compression 454 and run the motor at 6000rpm and make a nice 600HP for his boat. It was just about throttling it all the way up and run it wide open for a longer period.