Car Diesel Motor For Rubberduck

[kobus]

Hi all,any one who has done this before,i would like some tips,want to install a 1900cc tdi volkswagen diesel round about 73kw or 99hp in a 5m rubberduck of +- 300kg and it can carry 6 people,my plan is to do a direct drive thus i have to make most of my available 4500 rpm,what size prop and what about marinizing the motor??

[FAST FRED]

The first question is what HP will you expect the motor to run at at normal cruise?

99hp no chance about 50 -maybe 60 it should work.

FF

[kobus]

Hi fast Fred,yeh those ducks recomend 50- 100 hp im not gonna run it on wot all the time and mostly only 2 persons on bord do u think the 1900cc tdi volkswagen will do the trick?? the diesel got the torque low down to get it on a plane and these small diesels are real gems,im driving a 1500cc tdi and it is nice fast and alot of torque it is a renault megane and i ve kept it at 4000rpm easily, thanx anyhow what about marinazing?

[FAST FRED]

The problem is at road speeds you are only asking for a few hp. This engine will give less than 25 HP per gallon burned in an hour.

So if you travel 75 mph and get 40mpg , under 2 GPH consumption, you are burning about 40 -45 hp worth of fuel.

To maranize you will need to search for a transmission and drive plate to fit the VW. They may have a water cooled exhaust manifold too.

If no manifold is found , thats OK as good enough heat insulation on the manifold will work.

The next decision is finding a heat exchanger , a used one from a gas marinization will do fine,

To cool the heat exchanger a pump will need to be added to the boat. Most common is an engine driven , but I have seen electric units work just fine .

Finally the exhaust will have to be decided.
Probably a dry stack even with muffler would be to hard to live with , so a "riser" will be needed for the exhaust , so the cooling water can be dumped into the exhaust , on the far downside of the riser , to calm the noise and cool the exhaust.

FF