Rotary Engines: Would it work in a boat?
 

The R26B engine that won the 1991 LeMans was normally aspirated and had four rotors and three sequential spark plugs per rotor. The capacity is 2622 cc actual, rated by FIA formula at 4708 cc. It produced 700 bhp at 9000 rpm and 62 mkg torque at 6500 rpm (448 lb-ft). Fuel was electronically injected and consumption was 51.881 liters per 100 km at an average speed of 213.58 kph (excluding pit stops). The air intakes had continuously variable geometry controlled by the engine electronics. The transmission had 5 speeds (full synchromesh) from a Porsche design gearbox and a limited slip differential.


Well?

Re: Rotary Engines: Would it work in a boat?
 

You know this begs the question.......
Who cares? It ain't no big block.;)

I don't think the imput shaft of the drive would like 9000 rpm very much. Besides,the torque curve on a rotory is very tight, not really condusive to a one speed transmission.

Let see here...my bigblock makes 600hp @ 5500 and 650lbft @ 4000. So will it work? Yes. Will it live? No. Will it be fast? Depends on how heavy the boat is. That engine has to be 1/3 the weight of my big motor. It also costs 10 times as much.

I think you speed should be in MPH not kilo's[ i hope ] cause 213.58 kilo's per hour is not very fast, my old porsche turbo will run 260kph,

tehre is a company here on LI (in glencove) called rotary marine. And guess what???? they make rotary engines for boats.

They make 260hp supercharged 13b's puder. In a small boat, say 18 or less, it would be fun, where the torque isnt needed as much. I would be up to try it sometime.

I had three Rx 7's in the 80's and you cannot kill those engines. I think the concept for continuous propulsion is better than a reciprocating engine unfortunately good old cylinders are so prevalent that apart from Mazda there is no major companies doing serious R&D on those engines, and the cylinder culture is entrenched and here to stay.

Like airpacker said though they are very high reving engines. they take A TON of gas if you compare same cubic inches and run VERY VERY hot.

So on paper I would think they are better but no market no manufacturer.

Seems to me that one of the small jet boat manufacturers used a Wankle in their boat for a while. Used a TON of gas even when compared to a comparable two stroke motor. Jet pumps are not as susseptable to rpm's as an outdrive is, therefore the best application for a rotary engine might be a jet boat????

Rotary's are, in effect, a lot like a 2-stroke in that they are "port timed". This means that they can't be "cammed" for different desirable torque curves, they must be ported like a 2-stroke and this is somethng that can't be reversed.

They can, however, be ported for a broad torque curve and supercharged for massive amounts of power from a lightweight package.

Durability? Reliability? It all comes down to two things:
1) "oversize" rotors are EXPENSIVE and oversizing the double-trochoidal "cylinder walls" can only be done with specialized equipment.
2) Seals, Seals, Seals. Seals are used instead of rings. Seal wear is accelerated in a pressure-fed motor, and seal life is not as long as we would like to see it.

There have been one or two wankel aircraft motors certified, but I am think I remember hearing that they are no longer produced. Seal dependability was one of the issues.

Aircraft motors run at constant load. Boat motors run at constant load. Cars run at very light load except under acceleration.

I like rotaries. There's a guy putting them in jetskis and having pretty good results (close to 300hp).

As far as input shaft speed, hook em to a surface drive on a light boat. That'd be cool.

For a marine application, the variable timing and such would be a nightmare. Bolt a blower on it, fuel inject it, and rip.

Remember the little "beeper" that sounded on the early RX7's when you grossly overrevved it. We called it "the pull over and put the fanbelts back on" noise.

And what a cool little miniature Hitachi 4-barrel carb...

A few years ago at Team Scarab
Skunk works in Ventura CA. We had a project with Mazda and
rotory eng. to develop a motor
and install it in a Scarab 16ft Jet Sprint.
A lot of R&D work went on in
the ventura area during to
late 80s and thru mid 90s of
all kinds of boat designs.
The Rotory Motor was just one
of 14 motors tested in the
same 16ft JetBoat, I still own
that 1st boat.
Mike J.

Not enough torque for practical use. You would need many very large rotary’s to power an offshore boat. Not to mention they don't take kindly to detonation.

Roby

I remember it well. My father bought one new when I was 17. It took me about 3 days to hear that "Beeper." About 3 years later, my Dad was telling me about getting pissed off at someone in traffic, and he heard this "Beep" when he redlined the car passing the idiot. First time he ever heard it. Any idea how hard it was for me to keep a straight face? :D

There are some guys around here who run rotaries in their sand rails. Twin turbo charged, over 400 hp, and two guys can lift it into the frame without a cherry picker!! I was at Baker Engineering one afternoon a while back and they had one of these sitting on the floor. Pretty cool motor, really small, and according to him, really loud!! But he said the rail it went in was wicked fast.

Foul

LMAO :D:D:D:D

I'm with mroffshore, They can take a beating but rotaries with turbos are a totally different beast. They respond unbelievably well to boost but do not hold up. personally I think the n/a 13b has a wider torque curve than a comparable 4 cyl. I think if you ran a dry exhaust though the sound would drive you nuts.

General Motors tried it:
 

Back in the days when GM was trying wankel (rotary) engines (mid 70's) before they abandoned them, they had a custom built Donzi 28 CC with two 4 rotor wankels tied to Mercruiser outdrives. The thing went like stink, the motors took up hardly any room, and used about the same amount of gas as v8's. I know, I drove the boat.

Then GM scrapped the wankel program and EVERY motor that was built was pulled in and scrapped. There may be one surviving block somewhere in Warren, mich.

They replaced the rotaries with twin Merc 188's based off of the 302 Ford v8. They had to increase the size of the engine cover hatch, lost 10 mph top speed (weight), and the 188's were a DOG of an engine (no response).

The boat was named the "pflueger fun", Pflueger made fishing tackle.

Rotaries are light weight and have great power/weight ratios. They are dirty from an emmissions standpoint and that's what killed them from the Automotive market. Mazda only produces the RX8 for it's unique marketing of the wankel. They are not practical and are expensive with the emmission requirements of today. Otherwise everyone would be building them.

The Wankel has the ability to be marinized and I think would be great in personal watercraft and lighter smaller boats. You can tune them to make the all the power that would be needed at 6000 rpm or less.

Wannabe in Motor City
(OSO's peudo automotive historian)

WOW.......some great info guys!

Puder is correct. The company is Rotary Power International. I posted this site in the same subject from months ago. They have an engine that is 1000hp, its just that they stack the rotaries. The HP/ wt was very impressive. It will work in a boat. RPI has built them for military applications.
Unfortunately their website is not up.
Stock symbol is RPIN.

Re: General Motors tried it:
 

This is really nit-picky, but I believe the 188 was based off the 460. Like I said, pretty nit-picky. :cool:

There was an add in a magazene a while bach advertising a marinized rotary. I'll try to look for it.

I dont remember when, but i saw something on TV a long time back about rotary's....they said the engines have unlimited rpm potetioal due to the fact the have no valves to float or anythign liek that! Would be cool for marine but it still woudl be limited by gearing in the drives :)

When the R&D work was being done in ventura Rotory Marine
was located in Seattle Wash.
And Mazda North America is in
the Irvine CA. area.
I have a number of photos of
Mr. Kobayakawa Pres. of Mazda
riding in a Rotory powered
Scarib at Ventura Harbor with
Warren Robbins VP Scarab and Scarib doing the driving.
Mike J.

Cord

Yep, 170/188 Mercruiser was half of a 460.