what size fuel tank??

[0ldbloke]

Hi Guys..
have read the forum for quite a while but don't post often..
I would like some advice on which size fuel tank I need..
my outboard is a late 90's 2s Mariner on a 4m Honwave..
I haven't used the engine enough to know what sort of consumption I can get from it yet..
the usual use for the boat is weekend fishing.. day and overnight.. and some playtime of course!!
no particular area .. I vary from Plymouth to Scarborough coastline wise
I have a 30l hulk tank which came with the engine.. but am thinking I won't ever use as much on a weekend..
I'm more than happy to carry a smaller tank and have a spare fuel container either onboard or ashore..
or is it simply the case I'm showing my inexperience by not being happy with what I've got..
it's just I am always aware.. size isn't everything!! :0#

[m chappelow]

Hp size of your engine would be usefull ; )

[0ldbloke]

damn it... there was me trying to think of everything..
except the obvious!! :0#
it's a 15hp..

[willk]

That's a big tank for a small motor. IIWY I would hold on to the hulk and test your consumption. Put in a known volume and keep a note of your hours run and distance covered. This might seem a bit loose, but I've found that it gives a VERY good indication of what your ongoing consumption will be as it takes your rig and driving style into account. After you know that, you'll be well placed to decide how you want to proceed. You might find that a pair of 12l tanks work well for you for lots of reasons...

[Johnny5vikk]

Hi there. I have a 3.5 honwave with a 15 hp four stroke and I carry a 25 litre fuel tank. I fill it before every bass fishing trip, cover lots of miles in 10 hour days and mostly at full chat and have never used much more than half a tank. Hope this helps

[Peter_C]

I have a 40HP and carry 26 liters or so as it is a 6.6 gallon tank. Only once I have ever wished I had more gas, and fortunately I did in a spare tank. I ran out right in front of the Coast Guard station as I was pulling back up to the boat ramp.

Realistically you could cut that amount of fuel in half, unless you are doing big trips.

[0ldbloke]

much appreciate your answers guys..
I think this season as suggested by willk I'll stick with the tank I have..
as said it will give me a chance to see what sort of fuel use I average out at.. and at least I know I won't run out!!
and let's me take my time on that well know auction site to nab a couple of cheap 12l tanks as suggested by PeterC..
by the sounds of it from Johnny 12l is enough plus a spare will be my best bet in the long run..
I did think the tank was far bigger than I'd need.. but it came free..
and at last I have been proved right!!.. as I've always had to tell the girls I've met.. size isn't always important :0$

[Locozodiac]

On a 2 strokes engine expect a 12% fuel consumption of its HP at wot on flat waters. Example a 18 HP consumes 2.2 Gal/hour at wot, much less at 1/2 to 3/4 throttle.

Happy Boating

[SIBer]

With 15hp and at WOT I'd expect usage at 5 litres+ an hour.

Calculate 1/3 there, 1/3 back and 1/3 reserve.

How far do you go?

[Ribandmotorhome]

You can never carry too much fuel, but can always carry too little. 30 Litres will last all weekend!

[Searider]

I'd go for a couple of 12 litre tanks. Easy to carry to the pump.

With our Avon SR4.0 / 30hp Yam 2 stroke, its kept on the river and used for short trips and the occasional trip to Cowes. I didn't really know how much it used and went with a full 22 litre tank and two full 12 litre tanks for the trip from Hamble to Portsmouth, round Portsmouth and then back to Hamble, about 40 miles I think.
Used 17 litres.

Small boats don't use as much as you imagine.

Hope that helps.

[0ldbloke]

[QUOTE="Searider;596251"]I'd go for a couple of 12 litre tanks

thanks for more answers guys..
I took on board what's been said earlier and now..
I'm going for the two 12's.. one down and one and one to go..
but biding my time on that well known auction site for a bargain..
not sure whether it's the Scottish or the Yorkshire blood in me that doesn't like to dip too far into my pocket!!

[Ribandmotorhome]

I agree :-)

[kubcat]

My golden rule for boats is 1 litre of fuel per horsepower. It works for the kind of boating I do. A 12 litre tank and another to swap certainly sounds like a good idea to me.

It would be great to update this forum when you have used the boat for a while as feedback.

[willk]

Originally Posted by kubcat

My golden rule for boats is 1 litre of fuel per horsepower. It works for the kind of boating I do. A 12 litre tank and another to swap certainly sounds like a good idea to me.

Thinking about that. It sounds like an excellent rule of thumb!

[frankc]

I learned to use the rule of thirds after coming home on fumes once. One third out, one third back, and one third in reserve for times coming back got hairy. The times we dipped into that last third are not good memories and were generally wet rides with white knuckles.

[Ribandmotorhome]

Originally Posted by frankc

I learned to use the rule of thirds after coming home on fumes once. One third out, one third back, and one third in reserve for times coming back got hairy. The times we dipped into that last third are not good memories and were generally wet rides with white knuckles.

That's ok if you have a definite planned route though :-)
Also my dad had a phantom called 'white knuckles' brings back many memorable times!!

[dave3235]

Originally Posted by 0ldbloke

Hi Guys..
have read the forum for quite a while but don't post often..
I would like some advice on which size fuel tank I need..
my outboard is a late 90's 2s Mariner on a 4m Honwave..
I haven't used the engine enough to know what sort of consumption I can get from it yet..
the usual use for the boat is weekend fishing.. day and overnight.. and some playtime of course!!
no particular area .. I vary from Plymouth to Scarborough coastline wise
I have a 30l hulk tank which came with the engine.. but am thinking I won't ever use as much on a weekend..
I'm more than happy to carry a smaller tank and have a spare fuel container either onboard or ashore..
or is it simply the case I'm showing my inexperience by not being happy with what I've got..
it's just I am always aware.. size isn't everything!! :0#

Heres a little indicator I had a honwave 3.5 with a15hp 2stroke.Went from Brixham all the way to Blackpool sands, back to Dartmouth and up the estuary back to Brixham .Started with a12ltr and a 5ltr got back with still a 3rd left in the 12ltr tank that must be getting on for 15 miles if that is any good

[Locozodiac]

Will dependd entirely if making long or short outings and available sib space. Have been outing for years with 6 gal tanks factory delivered with engine, but my usual "long" outing just consumes max 2.5 gal.

With that amount my 18 HP can make + 60 Km cruises at around 1/2 -3/4 throttle perfect plane and max 1 extra mate on flat calm no wind sea conditions. So planning to change my 6 gal tank to a smaller 3 gal tank in a short time period as never fill my 6 gal tank fully.

Usually buy fresh fuel for that outing and try to consume it all, leftovers are near forbidden, ethanol issues.

Happy Boating

[Max...]

I always work on the well known rule of 10% of hp in gallons per hour at WOT - ie for a 15hp 2 stroke max consumption is 1 1/2 gallons or 6.75 litres an hour.

Our last day out we did 38 nm. Max speed was 19 kts but mostly crusing around 15 kts, actual moving average (including all the pootling about) was 9.5 kts over the 4 hours.

Used about 16 litres so 4 litres an hour which is nicely within the 6.75 litres and allows plenty of safety margin.

I use a RNLI flexi bladder which is a great solution if you can find one - it sits in the dead space on the side of a SIB, is lightweight and can be filled up to 30+ litres if you need to. We fill it up for a longer journey with say 20 litres or for shorter trips say 12 litres and re-fill if going out again after lunch.