Originally Posted by joakimhansson
How fast is a diesel compare to a outboard? If you take mercrusier 1,7 and a outboard with around 115-125 hp.
For me diesel is slow....but you can change me...??? or..
And offcause fuelconsumtion?
You will probably go faster with the 115 o/b in this comparison. I think I am right in saying though that the Merc 1.7 is 120hp 'at the engine'.... so by the time you reach the prop it is probably nearer to 100hp. The outboards will be rated 'at the prop'. My Humber Ocean Pro with the Merc 1.7 has a top speed of around 30 knots and cruses nicely at about 23 knots. (GPS readings) Not a race winner but a good cruiser.
Outboards are lighter than diesels so they will always have more 'go' than a similar powered diesel but that doesn't mean you can't get a fast diesel set-up. You'll just need a bit more horsepower I presume! (No doubt some engine expert can give us some comparison figures on that)
However, don't cast aside the thought of diesel. There are 3 very good reasons for considering it. (Even without the current price difference in the UK)
1) Fuel economy. I recently did 2 days cruising around the Scottish Islands, logging up 130 miles on the GPS. I refuelled to a full tank with 95 litres of diesel. Thatís 0.73 of a litre per mile!
2) Fuel Availability. Diesel is far more easily available at the dock than petrol, (in the UK anyway).
3) You are not sitting on a bomb! If your boat catches fire, at least you have a chance of putting it out with diesel!
Always diesel for me from now on! The Merc 1.7 is a nice little engine but there are now similar sized, more powerful engines available.