fuel tanks

[Ribtec1]

I thought that I would open a separate thread rather than side track the spare fuel can thread. I have a 6.5m ribtec that has 2 fuel tanks in the floor each with a capacity of 150 litres. I have a 3 way valve beside the fuel filter and I can easily change between tanks as needed . I have always found this an excellent option as I never have to carry additional tanks on long cruises. I wonder why more rib manufacturers do not incorporate additional tanks in the floor. The space is there for it so it would do away with trying to secure additional tanks around the deck or within seating.

[beamishken]

Possibly down to cost and potential warranty issues the more simple the boat the less to go wrong and the cheaper it is to manufacture
Not much to go wrong with a 25l outboard tank on the deck

[Last Tango]

Originally Posted by Ribtec1

I thought that I would open a separate thread rather than side track the spare fuel can thread. I have a 6.5m ribtec that has 2 fuel tanks in the floor each with a capacity of 150 litres. I have a 3 way valve beside the fuel filter and I can easily change between tanks as needed . I have always found this an excellent option as I never have to carry additional tanks on long cruises. I wonder why more rib manufacturers do not incorporate additional tanks in the floor. The space is there for it so it would do away with trying to secure additional tanks around the deck or within seating.

And when (not if) one of them starts leaking you'll be left with the dilemma, after butchering the deck to get at them, do I replace the one tank that's leaking or do I replace them both. (probably no option to go to one tank because of the under deck layout).....every silver lining has a cloud.

[willk]

Originally Posted by Last Tango

And when (not if) one of them starts leaking

I'm sure you've had a bad run of luck with tanks. I've seen you post variations on this theme - that ALL steel tanks fail eventually. I suppose taken literally, it would be true - everything fails eventually - just as the hull will too. So I'm interested in the timescale you have in mind? 5 - 10 - 15 years? I know LOTS of 15 yo RIBS that are on their original tanks and only two that aren't. One was very badly abused and I have no history on the other. So maybe you're thinking of older craft?

To the OP:

300L is a HUGE amount of fuel in a 6.5m RIB - way more than most users would require or wish to pay for building storage for! The long range tank in a 7.4m Stormforce is 300L ! It sounds like a special order in a Ribtec - maybe for a "Round Somewhere" style trip? The upside is you will NEVER run out of fuel, so long as you don't get complacent about refilling. The downside is that you have a lot of fuel aging below deck. Fuel that you have to get on the plane every time you pull away. Fuel that your engine is running a little harder to carry about. Unless you part fill them?


P.S. Hello from a bit further North East...

[gtflash]

Large tanks built in are great if you need them. Even better is separate or multiple tanks that can be isolated in the event of damage or contamination

The down side with manufactures filling every space with tanks is, if they fail or if they get filled with stuff they shouldn't it could then potentially be a drama to rectify, unless they have easy drain and cleaning facilities. My job is fixing things and when manufactures make any item without a way to service it, because it's" maintenance free" I can guarantee it will be harder to fix later.

The other down side to big tanks is the storage of lots of fuel which degrades and could collect condensation, and closer to my interest is weight Each litre of fuel ways approx 1kg. That's more weight to drag, and more importantly less speed. My mates 25ft boat gained nearly 20mph by loosing weight. He weighed all 600kg he removed on his wife's bathroom scales too

[willk]

Originally Posted by gtflash

...and closer to my interest is weight Each litre of fuel ways approx 1kg. That's more weight to drag, and more importantly less speed. My mates 25ft boat gained nearly 20mph by loosing weight. He weighed all 600kg he removed on his wife's bathroom scales too

Petrol is around 0.75kg/L - diesel closer to 0.85kg/L

I'm absolutely with you on the excess weights. I handball EVERYTHING out of the boat over the winter and reload in the spring - it's amazing what builds up. I'm guessing your mates boat wouldn't plane with the 600kg on there?

[Last Tango]

Originally Posted by willk

I'm sure you've had a bad run of luck with tanks. I've seen you post variations on this theme - that ALL steel tanks fail eventually. I suppose taken literally, it would be true - everything fails eventually - just as the hull will too. So I'm interested in the timescale you have in mind? 5 - 10 - 15 years? I know LOTS of 15 yo RIBS that are on their original tanks and only two that aren't. One was very badly abused and I have no history on the other. So maybe you're thinking of older craft?

I certainly have a bit of a jaded view about fuel tanks, not least because I fell off the boat, broke my arm and knocked my front teeth out when I was changing my tank last year. Mines was 15yrs old, the Ribeye was 9yrs old. My Fairline probably about 15 years old, Two Tremletts the same. I have had two Searays that were 20years old and still "ok" in so much as they weren't leaking but their appearance gave cause for concern. (Both aluminium tanks).
I don't count portable tanks because of the abuse I gave them but it would be interesting to poll the subject and find out others experiences.
Interestingly in both my own Coastine and the Ribeye there was no evidence of corrosion being a factor.

[gtflash]

Originally Posted by willk

Petrol is around 0.75kg/L - diesel closer to 0.85kg/L

I'm absolutely with you on the excess weights. I handball EVERYTHING out of the boat over the winter and reload in the spring - it's amazing what builds up. I'm guessing your mates boat wouldn't plane with the 600kg on there?

The boat did 45 ishmph before the diet... despite the v8 block

[willk]

Originally Posted by gtflash

The boat did 45 ishmph before the diet... despite the v8 block

600kg is a lot of cr@p !

[Ribtec1]

Originally Posted by Last Tango

And when (not if) one of them starts leaking you'll be left with the dilemma, after butchering the deck to get at them, do I replace the one tank that's leaking or do I replace them both. (probably no option to go to one tank because of the under deck layout).....every silver lining has a cloud.

My boat is approx 1999 and the only problems I had so far was that the fuel senders corroded which I replaced. I did have to drill an inspection hatch into the back tank to remove parts of the old sender that was blocking the fuel pipe. I would imagine that if 1 of the tanks gave trouble then I would remove it to see what the problem was. I would not remove a good tank unnecessarily.

[Ribtec1]

Originally Posted by willk

I'm sure you've had a bad run of luck with tanks. I've seen you post variations on this theme - that ALL steel tanks fail eventually. I suppose taken literally, it would be true - everything fails eventually - just as the hull will too. So I'm interested in the timescale you have in mind? 5 - 10 - 15 years? I know LOTS of 15 yo RIBS that are on their original tanks and only two that aren't. One was very badly abused and I have no history on the other. So maybe you're thinking of older craft?

To the OP:

300L is a HUGE amount of fuel in a 6.5m RIB - way more than most users would require or wish to pay for building storage for! The long range tank in a 7.4m Stormforce is 300L ! It sounds like a special order in a Ribtec - maybe for a "Round Somewhere" style trip? The upside is you will NEVER run out of fuel, so long as you don't get complacent about refilling. The downside is that you have a lot of fuel aging below deck. Fuel that you have to get on the plane every time you pull away. Fuel that your engine is running a little harder to carry about. Unless you part fill them?


P.S. Hello from a bit further North East...

Hi
Yes it is a lot of fuel but only when the both tanks are full. I was told that the boat was a stand-by boat for reporters of the camel trophy race.
I normally fill the back tank and keep a 50l reserve in the front tank. Then mid season I will reverse the procedure and fill the front tank and keep a reserve in the back tank.

[Ribtec1]

Originally Posted by gtflash

Large tanks built in are great if you need them. Even better is separate or multiple tanks that can be isolated in the event of damage or contamination

The down side with manufactures filling every space with tanks is, if they fail or if they get filled with stuff they shouldn't it could then potentially be a drama to rectify, unless they have easy drain and cleaning facilities. My job is fixing things and when manufactures make any item without a way to service it, because it's" maintenance free" I can guarantee it will be harder to fix later.

The other down side to big tanks is the storage of lots of fuel which degrades and could collect condensation, and closer to my interest is weight Each litre of fuel ways approx 1kg. That's more weight to drag, and more importantly less speed. My mates 25ft boat gained nearly 20mph by loosing weight. He weighed all 600kg he removed on his wife's bathroom scales too

Hi
Every day use the tanks would be nowhere full but for long trips whether the fuel is stored in containers on the deck or in tanks in the hull the weight will be the same.
I take the point about condensation but I have the boat for 9 years and it has not been an issue so far. I do have 1 of the old Yamahas that run on a mixture of petrol/oil/water/sand and rubber
The point regarding access is very valid. It appears on all boats there is very limited(or no) access to service/clean out tanks. Surely this should be made a priority. I mean we pay large sums for chartplotters, suspension seats, a frames etc but it appears very little thought goes to servicing a very important part of the boat

[willk]

Originally Posted by Ribtec1

a frames etc but it appears very little thought goes to servicing a very important part of the boat

There should generally be an access plate built around the sender unit. This can be removed and the back of the tank inspected/pumped. Bear in mind that any decent tank will be baffled and there is only very limited access to those parts, no matter where your tank is situated.

[office888]

Originally Posted by willk

300L is a HUGE amount of fuel in a 6.5m RIB - way more than most users would require or wish to pay for building storage for! The long range tank in a 7.4m Stormforce is 300L ! It sounds like a special order in a Ribtec - maybe for a "Round Somewhere" style trip? The upside is you will NEVER run out of fuel, so long as you don't get complacent about refilling. The downside is that you have a lot of fuel aging below deck. Fuel that you have to get on the plane every time you pull away. Fuel that your engine is running a little harder to carry about. Unless you part fill them?

That's a pretty common amount of fuel for a boat that size in the USA.

Kinda funny too... The Zodiac Pro Open 650 actually has two tank capacities. The French non-EPA tank has a 31 gallon (120L) capacity. The EPA tank is bigger, at 53 gallons (200L).


People here want to run out 30 - 50 miles, and back, and still have their 1/3 reserve.

[willk]

Originally Posted by office888

People here want to run out 30 - 50 miles, and back, and still have their 1/3 reserve.

Which is compatible with a 200L (53USG) tank. 300L (79 US gallons) in a 6.5m boat is most unusual here - I was confident it was a special order