Every since I had my first RX-7 in 1982 - I always thought - why don't they put the Rotary engine in boats? Boats run at high RPM all the time and the Rotary engine in a boat is perfect match.

Well they finally did it check out these links. My next boat will have a Rotary engine to go with my RX-8.

http://www.rotarypowermarine.com/

http://www.boatingnews.com/rotarymarine.htm

:D

 

If Mazda can put a 500 HP 4 rotor in a boat -- why can't they put one in my RX-8? I think that would end all discussion on torque, power and any comparison to an S2000, 350Z, wrx, or evo. I guess then we would have to put up with Viper and Ferrari comparos :D

 

I always thought boat engines were all about torque and lower RPM, so they run for days at sensibel revs and decent reliability?

 

Diesel engines run at lower RPM and put out more torque. Gas engines in a boat run at close to max RPM because there are no gears. I run my boat at 4,000 rpm (V8's) for cruising and top out at 5200 RPM. V8 in a car - 2000 rpm and your going around 60 - 65 mph. My boat is 28 ft and has two V8's and at 4000 rpm I’m going approx 50 - 55 mph. This puts a lot of stress on the engines and only last around 400 - 800 hrs. Rotary engines are made to run at high rpm and will not damage it. This is why the Rotary engine will work well in the marine environment.

:D

 

All that is exactly right. Plus, the Rotary engine is smooth and comparatively quiet at high RPMs. Which is exactly opposite from most marine engines, especially outboards. One aspect that is really nice is the lack of vibration, which on some boats gets annoying after a while.

 

another two reasons rotaries would be exceptional in a marine environment is for reliability reasons and fuel economy.

rotaries use the least fuel in a cruising environment, ie highway, airplane, or in water.

the inherrent nature of the marine environment, it's practically impossible to not have enough water to cool down your engine.

 

Only if you remember to remove that little plug over the water intake. Don't ask me why I know this:headsmack

 

The reason for that is the EMISSIONS RATE. the emissions on Rotary engines are very hihg and thats what makes them not street legal and where in the US. i wish that they would make the emissions limit high but it dosent look like they will do that for a while now.

 

Where did you get this information?!?

Rotaries by nature are not the most fuel effiecient cars by far!
Torque is an issue with marine equipment, therefore a diesel conversion would help, but more stress is placed on diesel engines then gas, so reliability might be an issue in the long term.

 

we're not talking about cars, we're talking about boats.

wankel engines are more fuel efficient than even the best 2 stroke engines (except for the OMC FICHT system, but that's a POS anyways... the right idea, same as what Mazda's done with the rotary, but they haven't pulled it off), and with less emissions too... with the RENESIS, you're looking at near-4stroke emissions compliance and fuel economy, with 2 stroke power, simplicity, and reliability.

who ever said that 2 strokes have a lot of torque anyways?? and no one, and i mean no one uses diesel engines for pleasure boating: those're just for tugs... not to mention you can't really just "convert" a wankel engine to deisel: the Mazda design would have to be altered significantly, so that the width of the rotors was narrowed quite a bit in relation to the "stroke" (upon which all of the cross-sectional geometry is fixed) so that the compression ratio could be high enough...

 

Where did you come up with "and i mean no one uses diesel engines for pleasure boating" That is not true at all!

Diesel's are greatly used in pleasure boating. They are more expensive but widely used in all types of pleasure boating, from small boats, cruisers, sport fisherman's, yachts, and some performance boats.