Alcanboats Forum

I was reading in the Alcan 37 owners manual that the boat came equiped with either twin gas @ 170 hp each, or twin diesel @ 92 hp each (there was one more twin gas option @ 155 hp each)

I was wondering why the diesels are so much less power than the gas - perhaps not enougth room to fit a more powerful diesel?

Also does this mean the the diesel version was much slower than the gas version?

Hey wallyg,
I had the original diesels in mine when we got her. Volvo MD29A's.
Not a whole bunch of info available on them, and Volvo themselves won't even give you the time of day regarding them. Findings parts was next to impossible as was finding someone willing to work on them.
Finally switched them out for 4cyl Volco AQD130's gassers. These aren't new and maybe not the perfect answer, but I'm happy with them and with the price of refit.

Good information to know - thanks Terry.

Do you know if the diesel version was much slower than the gas version?

The diesels were only 90hp and we cruised comfortably at 6 knots at 1800rpm. Had her up a little faster at times but never seemed worth the extra noise, vibration and, presumably, fuel.

But now, with these AQD130's we cruised comfortably at 6 knots at 1800rpm. Had her up a little faster at times but never seemed worth the extra noise, vibration and, presumably, fuel.

We've really got nowhere to go, so speed isn't a big factor with us. There are lots of days when we don't even leave the dock as we've got a pretty good set-up right where we are.

Thanks for the reply - Understood.

I was just curious why the Alcan manufacturer would put wildly ( i.e. gas = 2x diesel) different horsepower motors in the same boat.

Walt

The selection of diesel engine might have been more a case of engine weight than engine HP.
1960 era marine diesel engines were massive compared to the HP that they could deliver.
There is an excellent article, by David Pearson, in the Alcan website tech section on HP vs hull speed for an Alwest.
http://www.alcanboats.com/alcan_hull_dynamics.htm
HP is HP. It would be arrived at differently with a slow reving high torque diesel than with a high reving lower torque gasoline engine.
But yes . . . 2 x 90HP will deliver a max hull speed much lower than 2 x 170 HP.