Fuel consumption on a Sealine 310

[Prima]

Firstly, I'll start off by apologising, I know many of you will have read this kind of thread a thousand times, so sorry for this question but I am confused by something I just read (based on what I've read before on this subject).

So, here goes... I just came across a VERY old advert for a Sealine 310 Ambassador which states this

Fuel consumption 1.5 UK Gallons per hour at 20 knots cruising speed

Surely that can't be right can it? Isn't it more likely to be 1.5 MPG at 20 knots?

The advert is here:
http://www.boatmatch.com/boat-for-sale-print.php?boat=1308&buy=Sealine-310+ambassador

 

[CLB]

Firstly, I'll start off by apologising, I know many of you will have read this kind of thread a thousand times, so sorry for this question but I am confused by something I just read (based on what I've read before on this subject).

So, here goes... I just came across a VERY old advert for a Sealine 310 Ambassador which states this

Surely that can't be right can it? Isn't it more likely to be 1.5 MPG at 20 knots?

The advert is here:
http://www.boatmatch.com/boat-for-sale-print.php?boat=1308&buy=Sealine-310+ambassador

Yes, 1.5mpg would be about right at cruising speed, maybe a tad better.

 

[Prima]

Thanks. I thought so but as my signature states I am a noob and prone to asking daft questions I got confused when I saw the figure quoted

Better to ask and be 100% sure though

Just out of interest, how many gallons per hour would a 310 use just pottering around at about 8-10 knots? That's a type of figure I have never seen quoted anywhere.

 

[Greg2]

8-10 knots would not be good because it would be above hull displacement speed but not on the plane. Max hull speed is probably around 6-7 knots.....after that it will be pushing a hole in the water until it lifts onto the plane.

At displacement speed probably around 1.5 to 2 gallons per hour, maybe a little less

 

[Prima]

8-10 knots would not be good because it would be above hull displacement speed but not on the plane. Max hull speed is probably around 6-7 knots.....after that it will be pushing a hole in the water until it lifts onto the plane.

At displacement speed probably around 1.5 to 2 gallons per hour, maybe a little less

Thanks, little bits of info like that should be more readily available to newbies like myself I think - the general view seems (or mine was initially) to be that the cost of fuel for boating is always going to be high, but if those of us on a limited budget just want to go for a slow cruise for a couple of hours it needn't be so expensive.

I guess the reality is different though with the urge to go WOT far too tempting

 

[CLB]

What you need to be aware of is that boats that are designed to go fast, are not always the best at going slow. They are ok if the sea is flat, but any chop and they need some speed on to stop the wallowing and to give them some directional stability. You would be surprised at how rare it is to go out in truly flat seas. What you may end up doung is putting a bit of speed on, to improve comfort and bring the speed up to around 10 knots, which actually provides worse fuel economy than being properly in the plane.

 

[Prima]

Thanks CLB, info taken on board - I'm not too bothered about the fuel economy to be honest, really just trying to gain as much info and knowledge on everything before I actually buy a boat, I am still waiting for my house sale to complete though so plenty of time to learn from all you more experienced folk so I don't make a complete mess of everything