Fuel Consumption 4.3, 5.0 etc

[mfox]

Hi,

I'm a newbie looking to buy a used sportsboat for skiing, dayboating etc. but I'm struggling to work out what the fuel costs would be for various craft. I know it will be a lot but I want to weigh the extra costs of a larger boat against increased usability and seakeeping.

I cant tow so it will be moored. The original plan was to run LPG, but that seems to have very limited availablilty on the South Coast and getting a mooring nearby looks unlikely.

I appreciate that individual craft vary but was just after some ball park gph figures for 21' cuddy with 4.3 Mercruiser versus, a 23' cuddy with 5.0 or 5.7 versus 18' Bowrider with 3.0.

The boat would have 4 on board plus a skier. I'm thinking a cuddy would give me more versatility than a BR but obviously adds weight. I'd be grateful for any info or real-world experience or just a steer in the right direction.

Many Thanks

Mike

 

[jhr]

I've got a 21 ft 6 in cuddy with a 5.0 efi. It's quite heavy for its size (nearly 2 tonnes) and I get about 3 nmpg at 3,500 rpm - about 25 knots, with a clean bottom. I reckon that would probably work out similar to a light 23-footer.

Have run at full bore (4,800 rpm) once or twice, but speed and fuel consumption were both too scary to repeat! /forums/images/graemlins/smile.gif

I'd go for a cuddy every time. Bow riders are fine until you catch a snootful. And you will........

 

[[2068]]

My younger bro's Rinker 232 with a 5.0EFI seems to use about 11 Gallons an hour at a fast cruise, if that helps.

dv.

 

[AJW]

I think there is a rough rule of thumb that for every 100hp you will burn 6ph at Wide Open Throttle. So for a 205hp thats 12gphish flat out. You should certainly figure somewhere around 1-1.5l per nm I'd say.

Dont go for a bowrider. A cuddy offers more versatility and IMHO is safer in coastal UK conditions. As JHR says when you stuff it (which inevitably you will do at some point) then you'll appreciate being in a cuddy all the more!

 

[gjgm]

a petrol fuel consumption curve looks a bit like a J... at some point you are guzzling a hell of fuel for a marginal increase in speed. I ve heard last 10cpt in speed doubles consumption. Dunno, but you get the picture! That said, how you use the boat has an enormous effect. For 3.0 5.0 and 5.7 I'd go for 5,8,10 GPH.. but you dont need to drive much harder to be doing 10,15 and 20 perhaps. Bear in mind frequent hard acceleration for pulling a skier up, drinks alot, and any boat will have an optimum cruising speed.Say 30knt , and in an hour you cover a fair distance, sea,etc permitting. So it might seem alot per hour, but maybe you arent running for hour after hour anyway. Average use is 50 hours per year.. gives you a benchmark.
Bowrider/cuddy.. both have their uses. If you re dayboating in sheltered waters, a bowrider is fine. And if you re doing alot of waterskiing,cove hoping etc, then you are going to be somewhere sheltered! If your ambitions are for further afield cruising, and 18ft bowrider isnt the thing. But whatever, 23ft will be alot better than 21ft which will be alot better than 18ft, in my opinion of "better". Talk to boaters around where you ll be boating, find out if what they want from a boat is the same as you (otherwise the opinion isnt so valuable), and see what boats they have.

 

[mfox]

Thanks everyone, certainly given me some pointers. Much appreciated