Real world fuel costs

[Pezza]

Hi everyone, I do not know anything about boats so please excuse my questions. I'm becoming interested in boat ownership and trying to work out is this really for me. This is a very vague question, I know there are many factors.
For a 25-27ft cabin cruiser how much would it cost in fuel to get from Lymington to Dartmouth and lyminton round the Isle of White, (not a cruiser with twin 1000 hp super charged engines. Just run of the mill standard engines that would be more for economy travel. Also are there diesel powered ones and again how much to do the above journey. Many thanks

 

[Assassin]

Many are diesels and for good reason, economy, reliability, durability, and safety, but don't discount petrol.

Basically you are asking how long is a piece of string as you need sufficient power for your boat and a little in reserve, there are many engines around the 150-250 hp mark and a single diesel would give displacement speeds which gives economy; many factors affect economy and a clean boat is first, closely followed by the correct set up to ensure the powertrain is matched to the boat, and the performance you require; economy varies and the most important factors are tides and on water conditions.

 

[julians]

At 20-25 knots I get about 4.5 miles per gallon in my 25 foot boat that has a single diesel engine of 260 bhp.

 

[Canopy Locked]

For diesel in a semi displacement boat I have always found the following to be a good rule of thumb 1 Litre / Hr per 10HP = 300hp engine will use 30 Ltr / Hr. Obviously this can vary tremendously as if you opened the taps to WOT you might be using 3 x the fuel for a relatively small increase in RPM.

 

[gordmac]

The old rule of thumb for a displacement boat of about 8m would be a gallon an hour, about 6kn speed. A modern engine may be nearer 3l per hour.
A Seaward 25, twin diesel on shafts will use about 1.7l/m between 10 and 17kn. About 0.5 l/m 5.5kn. Between those speeds is to be avoided. Info from Seaward.
A Botnia Targa 25, single diesel with outdrive, will use less than 1l/m between 14 and 28kn, I think that came from a boat test.