two engines on centerline, Filipino Banca

Here is a youtube video showing a largish Filipino Banca, a Banca is a double outrigger. One thing of note is that the boat has two engines on the centerline, one forward and lower, the other higher and aft. Both have long shafts. I assume this gives some redundancy , and fits into the long narrow hullshape, have never seen that before

 

Didn't seem that good for grounding protection, but hard to tell from the vision.

 

I have a hard time understanding why anyone would want a low prop. Seems like the main use of the low engine is striaght propulsion, but in a narrow boat, the real purpose may be constraints on the engine bay.

 

Overall it is a terrible design. The aft prop will operate in the wash of the forward prop. A piece of fishing monofilament as a rudder stop is completely useless. Monofilament instead of a cotter pin is also a bad idea. The main advantage of twin engines mounted side by side is for maneuvering at low speed. I think this deserves thumbs down.

 

I would have thought that with two engines, the obvious answer would have been a catamaran.

 

The consensus is that this boat is a bad idea. Hopefully peter will shoot another video and get us some information on how it all works out. Seems that these guys did what they could with what they had available. It's different alright. I understand what you are all saying but I've always liked people who have the courage to try something different.

 

I can understand it if restricted to a single engine, but a catamaran would seem to have made better use of two engines. But, I am sure they are practical people, and there may be good reasons for preferring this way.

 

If you need the power of two engines, it is common to bolt one inline with the other and connect the assembly to a single shaft.

 

One other thought I had for a purpose would be that the design tends to cavitate on the aft prop and instead of dealing with the cavitation; someone decided to put the lower drive in. Or, they always run the drive low and were always taking outbthe low prop so they added the high prop in a stroke of redneck genius.

Confusing for sure.