Concept conceived! Wankels....
 

We have a winner....Wankel motors in the Baja.

I recently purchased a 370 Force as a second boat. The 320 Force that I have now is serving me well, but knowing my boat habits, it could serve better.

Before purchasing the 370 Force, I realized I wanted more cuddy space and more deck space. Well, the 370 certainly satisfies my need for a bigger cuddy...however, the deck is roughly the same size. So for a guy who likes to fish, dive, booze cruise with friends and then hang out, this small cockpit won't do.

I've decided today, my Force 370 will receive a total of 6 Mazda rotary engines. Three engines will be coupled per side via a design in my head.... then directly coupled to the Bravo drives. Goal is 600 hp per side to get me into the 60s, maybe 70. The motors will be naturally aspirated and if set up correctly...maybe outlast the boat.

Now here is the good part...rear bench and sundeck go away. There will be lounge seating and under the step up for the transom will be a generator. The six 13B rotors are small enough so that the floor deck can maintain height from the helm clear back to the transom...this allows for fishing, diving, cruising and maybe some quick change out bolsters for a large crew to hit some water comfortably. I'm guessing the short coming that I have learned with my Force 320 is a common theme amongst most go-fast boaters. Rest assured, drawings will be produced and if there is an interest, I might make copies of what I have come up with.

Rotaries love continous power and can be made to be very quiet....things I'ved learned having developed a jetski with a Mazda 13B.
:party-smiley-048:

That sounds cool. Let us know how it works out. I have the 320 Force as well. Great boat..

600 HP, how much torque will they put out and at what RPM's?

Depends on the setup..the porting and manifold pressure will dictate what torque you'll see at what RPM. There is flexibility here and I will be sure to understand the prop curves before nailing down the motor configurations. Right now, I'm planning on 600hp at or around 6000-6500 RPM.

I'm excited too..first stage will be the difficult and the big question mark. Basically, running the seating and sundeck arrangement as I have it now with rotary motors. If I'm happy with the rotary mntors, I'll proceed in the new deck arrangement. First year will be devoted to the motor/propulsion, second year, if concept permits, will be interior/deck reconfiguration. Very exciting and a way to give some rebirth to these old boats!

I hope you've got a high limit on your gas card, you're going to need it with those gas suckers!

Post all the pics you can.

Ut Oh....

Hmmmm...first stumbling block. I measured wrong. I can't get 3 two rotor motors installed as initially planned....short by about an inch or so if accessories are included.

Now what! Well, I can either supercharge 2 two rotors or revert back to the 454s. If I revert back to the 454s, about one foot of deck space will be lost on the longitudinal axis. Plenty of space to be had with the 454s and seats moved further aft and a storage area would be included of the would-be very short sundeck. So now the quandry, do I attempt to pull this off with rotaries or stick with BBCs and lose about one foot of deck space? The lazy side of me says stick with 454s...the crazy engineer side of me says go with two 2 rotor motors (per side) fed by roots type blowers. This will take more pondering for sure...it was a slam dunk with three 2 rotor N/A rotary motors per side. Can't believe the wasted space with the existing 454s. At minimum, this needs to be addressed.

If you want to ever really use this boat , stick with the BBC.

Rexx you are really thinking out of the box bro. I like that and it would be pretty cool, but I have to agree with Kennyo and say stick with the BBC.

There is no sub for cubic inches and torque in boating.

Best of luck with the project and we look forward to seeing pictures.

Very unfortunate that it's a matter of a few inches with the rotaries. Realistically, I would need three per side which is the four stroke equivalent of 480 cid. Turbocharging two 2 rotor motors does not get the torque there. So I'm stuck. I was thinking today that I could make a custom eccentric shaft to make a compact 6 rotor motor but this is a project in of itself let alone a boat I have to restore. So for now, it looks like I will take a few 502 blocks and get them pumped up to 540 or 560 cubes...reorganize the deck and make everything tight.

I'm surprised a kit does not exist for a 6 rotor mazda rotary...it would be so compact and have so many applications. But, I really need to concentrate on the boat itself....maybe I'll be inspired to go rotary down the road by producing a custom motor.

It's not the power density, lightweight or space savings...just seems that a 600 or 700 hp rotary would be a perfect match for the Bravo unit. Many people have told me.....if you build a BBC turbo or supercharged, stay out of the throttle or the torque will tear the drive up. So naturally, a rotary having less torque but impressive horsepower seems to be a match in heaven for Bravo one drives. It really comes down to....we are not horsepower limited, but drive limited. Anyone of us can build a high horsepower motor, but getting a drive to "put up with" the torque is a different story.

I got this Force 370 for $8k...mainly bought it for its beautiful cuddy. Now looking at my Force 320.....it seems to be the difference of an impressive go-fast boat versus a bayliner. I love my 320...but time to graduate to the 370. I'm just cautious of the fact of how much power it will take to move this big beast over the 320...it's bigger in every dimension!