Inboard Air cooled Surface Drive

[flathead65]

View attachment 179863 View attachment 179863 View attachment 179863 View attachment 179864

 

[bajansailor]

Impressive videos!
What is the rated power output of the engine?
Do you steer the whole engine, in similar fashion to the Thai longtail boats?

 

[flathead65]

The engine is a 22 hp V-twin. Yes you steer the whole engine.

 

[DogCavalry]

Fantastic videos! How is she getting on the plane? How big a prop? How fast, how heavy?

 

[baeckmo]

Nice setup, good job!

 

[flathead65]

The boat gets right up on step. The prop is a 9"x5. I would guess mid 20's mph ( I haven't done a gps). The boat is 16ft. x 48" all welded .125" so, quite a bit heavier than most your typical jon boats. The engine weighs 100 lbs all stock except for the exhaust.
22hp. gets her moving right along.

 

[flathead65]

Nice setup, good job!

Thanks baeckmo.

 

[DogCavalry]

I second @baeckmo 's opinion

 

[flathead65]

Thanks again.

 

[philSweet]

How did you get your hands on a Briggs Vanguard? I've got two broken ones I'm having to rebuild because new ones are unobtainable. No one can even tell me when they can get me one - just "not in the next six months." I just ordered about $400 worth of parts today to rebuild one of them. We get about 6000 hours out of them at 2850 rpm. But I can't stop the guys from winding them up to 3000rpm.

 

[flathead65]

It's a Harbor Freight Predator. Interesting about the Briggs though. I wonder what all the mudmotor manufacturers are doing for engines?

 

[flathead65]

The shallow water capabilities of the drive.

 

[flathead65]

In "The Dewdney" video you can see the extension spring absorbing bottom strikes. It also suspends the engine up against the manual trim adjuster. That coupled with trim tabs on the protective skeg keep the prop in the water and provide a very neutral tiller. The gimbal gives ample steering and there is plenty of trim adjustment. The shaft assembly comes about a foot out of the water. I wanted to build the direct coupled shaft /engine gimbaled arrangement of the Thai longtail with the thru transom design of the Burmese boats for low shaft angle. The shaft is 32" more like the American outboard surface drives. So far it is working for my purposes.

 

[flathead65]

 

[flathead65]