Wankel engines in boats?

[RotaryRacer]

Re: Wankel engines in boats?

Wankels certainly have pros and cons.

Ironically, the biggest con is probably that there is a significant lack of development going into them.

Mazda is the only major company that has had more than just a passing affair with the design. Imagine if large OEMs spent the kind of resources they have spent over the years on the piston motors. Think about how piston motors have developed over the last 100 years. Think about all the shortcomings that have been overcome.

There are still companies that look at rotarys from time to time. They spend a lot of money and develop motors for specific tasks. Unfortunately, they usually don't have the financial backing to push a product to the mainstream market.

Here is the latest example:

http://rotarynews.com/node/view/1150

http://www.offshoreonly.com/forums/...sion/247829-r12-engine-2-400-hp-pump-gas.html

The biggest inherent advantage is the lack of moving parts. Add to that the small size and low weight for a given power output and you have a pretty interesting starting point.

 

[Summer Fun]

Re: Wankel engines in boats?

2400hp from that little engine. . .

2 of them would make my boat go mach 1.

 

[superbenk]

Re: Wankel engines in boats?

HP to weight ratio of the Wankel really impresses me. I was reading on Wikipedia that a Wankel generally produces the same HP of a similar piston engine with twice the displacement of the Wankel! That coupled with the lack of vibration and moving parts sounds really cool. Plus the fact that a Wankel seems to accelerate smoother and be more responsive to throttle input seems especially fitting for a boat application where you're essentially mitigating slip to produce torque, etc.

Heat & seals seem to be the big weakness in Wankels. Oh, one other thing I was reading on Wikipedia is that the Wankel tends to not fail catastrophically like a piston engine can. Basically when something goes wrong it's a seal or something and while the engine is dramatically crippled, it can still limp along. That's another thing that would seem to be a big advantage out on the water.

From Wikipedia:

"Wankel engines that operate within their original design parameters are almost immune to catastrophic failure. A Wankel engine that loses compression, cooling or oil pressure will lose a large amount of power, and will die over a short period of time; however, it will usually continue to produce some power during that time. Piston engines under the same circumstances are prone to seizing or breaking parts that almost certainly results in major internal damage of the engine and an instant loss of power. For this reason, Wankel engines are very well suited to snowmobiles and aircraft, which often take users into remote places where a failure could result in frostbite or death."

 

[smokeonthewater]

Re: Wankel engines in boats?

PBJT you crack me up..... the use of a transmission has NOTHING at all to do with the choice of top speed operating rpm.... You did start to catch on with the "they don't want to lose bottom end" part.
What you aren't catching is that unless the transmission is overdrive then high gear is the same as not having a trans at all with the exception of the drag that will occur while passing through the trans. My POINT is that we don't have them because we don't need them not because they won't work. As you said the slow acceleration we get while getting on plane is acceptable.


On to the op's question it all boils down to return on investment..... It just isn't worth it to the manufacturers to mess with it when they can just slap in the same old engine design and sell some boats... there isn't really any competition other than making the boats flashy enough to hook a passing consumer.. kind of like selling fishing lures

 

[H20Rat]

Re: Wankel engines in boats?

One good thing about it is that you would never have to change oil!

(yes, i know, they have oil. Talk to almost any rotary owner, they burn/leak it out at a fast enough rate to more than make up for oil changes!)

 

[MTboatguy]

Re: Wankel engines in boats?

A buddy of mine was a grand national drag champion with over 200 wins to his credit at national events, he ran an RX-3SP until they regulated his class out of existence. The rotary motors make a ton of power and was good in 1/4 drags..we tried playing with a 3 rotor motor in a boat and just did not work out.. I am sure that if it could be done, he would have been able to do it, he was one of the best rotary mechanics in the US and consulted with and for Mazda quite a bit. His car name was the Samurai Warrior.. he built me a RX-7 with a custom motor in it and it would easily turn 12,000 rpm's and the car would hit 190mph on the straights at the race track, but the con side, that car ate more gas than my old 66 Plymouth Satellite with a 426 hemi in it..also, the high performance rotary is finicky, and needs to be torn down and rebuilt quite often. Another thing, when running at high RPM, they are deafening and can cause extreme hearing damage..

 

[Super Sportster]

Re: Wankel engines in boats?

A buddy of mine was a grand national drag champion with over 200 wins to his credit at national events, he ran an RX-3SP until they regulated his class out of existence. The rotary motors make a ton of power and was good in 1/4 drags..we tried playing with a 3 rotor motor in a boat and just did not work out.. I am sure that if it could be done, he would have been able to do it, he was one of the best rotary mechanics in the US and consulted with and for Mazda quite a bit. His car name was the Samurai Warrior....

Terry Hoard???

 

[MTboatguy]

Re: Wankel engines in boats?

Terry Hoard???

Yuppers, it is Terry, I have not talked to him for years, but am good friends with him...

Does he still live in OR? Like I said, it has been many years since I talked to him....

 

[Super Sportster]

Re: Wankel engines in boats?

Yuppers, it is Terry, I have not talked to him for years, but am good friends with him...

Does he still live in OR? Like I said, it has been many years since I talked to him....

Figured it had to be him, personally I don't know him, my brother was his age. Don't know if he's still around these parts.

I remember watching the Samuri run at PIR, I believe that was the R100 bodied car, it was a screamer. There was another competitor, The Rising Sun. Both cars were screamers. As I recall Terry was right on top of these when the first Mazda's arrived. As I recall he had his own shop years ago.

 

[MTboatguy]

Re: Wankel engines in boats?

Figured it had to be him, personally I don't know him, my brother was his age. Don't know if he's still around these parts.

I remember watching the Samuri run at PIR, I believe that was the R100 bodied car, it was a screamer. There was another competitor, The Rising Sun. Both cars were screamers. As I recall Terry was right on top of these when the first Mazda's arrived. As I recall he had his own shop years ago.

Yes,

He owned Brapp Industries, his shop was 1 block from the corner of 82nd ave and Sandy Blvd, spent a lot of time in that shop and worked there every once in a while when he was short handed..the R100 was his first race car and the RX-3SP was the one he finished up with..Nice guy, and he knew his stuff when it came to the rotary engine!

 

[Hogger]

Re: Wankel engines in boats?

Had to add this one too. Watch it to the end.
Rotary ski boat

 

[scoutboater]

Re: Wankel engines in boats?

If I remember correctly the Wankel engine as no RPM limitations .

It just keeps going and going ... am I right ??.

I was told by a guy who used to drag race them that the only thing limiting his speed was how much air and fuel he could get in and how much exhaust he could get out.

Now, it has been pointed out that some of the seals will chatter at extended high speed, but idk anything about that. And like I said, this guy was drag racing. Not exactly long runs...

 

[MTboatguy]

Re: Wankel engines in boats?

Being honest with you, I don't think anyone would want the associated maintenance costs of putting a rotary engine in this applications, high performance rotaries are noting but expensive..