Fuel leak - under deck tank

[diver 1]

Well recommended. I only found out about it after searching about possible under deck tank leaks and overfilling on boats

[Crosshouse RIBS]

We have just completed working on a Ribeye 7.85 and we fitted a 92 l tank into the back seat for the owner to get through the season and then in the winter we will remove his deck and fit a new tank (preferably Plastic).

Its not that tricky to diagnose the problem with the tank.

Does your fuel filter have any rust in it or sludge that reacts to a magnet.
Does the fuel have excess amounts of water in it
Does the fuel have a good colour?
Is there any sludge in the botton of the tank under sthe fuel level sender
Is the Bilge water at all fuely

if your Tank does need replacing then I believe they have a 225l capacity and run about 2.8 meters long. they are fairly narrow so you can make a good job of cutting out the deck and get it replaced very firmly and quite cheaply as its not very fiddly to make new supports for the substrate. i think you'd have to allow £400 pounds for a new tank..

I would very much advise you to resist the temptation to get the old tank out and repair it as its more than likely THE tank would go again due to the age of the material. ts 91 in dog years

Hopefully your tank will check out ok and its a nice easy cheap fix

[ArunDivers]

Hi Andy, browsing the RibNet site I saw your item about your fuel tank. We had the same problem, took us 3 years to admit to fuel tank was leaking and concede to getting the tank taken out. Tried deck tanks but as you say this changed the boat balance. When the tank was taken out we found the stainless steel had severe electrolysis, probably because of a broken earth strap. We found a local fabracitor to skin over the exixting tank, cheaper than a new custom tank and so far so good. Local RIB boatyard had to cut the floor out with the main consule and reinstate everything, I think it was about £800. The reskin was £500. We had quotes of £3000+. Another reason it took so long to commit to the repair. Not sure if this has been any help, but we are pleased it has now been done. Gary

[Andy0]

Originally Posted by diver 1

I've replaced all the fuel lines on my ribcraft including the filler and breather, and repalced fuel fender gaskets. I've fitted a Barton fuel whistle to the breather line this is great - you know exactly when to stop adding fuel because the whistle noise of displaced air stops thus indicating tank is full. Stops you from filling up the filler and breather lines as well!

I'll be looking into getting a Barton fuel whistle, too. Thanks for mentioning it.

[SteveHall]

I can see a rush coming on the fuel whistles

[Andy0]

Originally Posted by ArunDivers

Hi Andy, browsing the RibNet site I saw your item about your fuel tank. We had the same problem, took us 3 years to admit to fuel tank was leaking and concede to getting the tank taken out. Tried deck tanks but as you say this changed the boat balance. When the tank was taken out we found the stainless steel had severe electrolysis, probably because of a broken earth strap. We found a local fabracitor to skin over the exixting tank, cheaper than a new custom tank and so far so good. Local RIB boatyard had to cut the floor out with the main consule and reinstate everything, I think it was about £800. The reskin was £500. We had quotes of £3000+. Another reason it took so long to commit to the repair. Not sure if this has been any help, but we are pleased it has now been done. Gary

Thanks Gary, below deck tanks seem to be an issue, even though I have heard many times that they are supposed to outlast the hull!

[Andy0]

The latest is that the tank does not hold pressure and so it has failed. The job is now to remove the deck and replace the tank and refit the deck. We have invited quotes. Ribeye can do it but the lead-time for the tank is prohibitedly long as this would come from overseas. The decision now is what material to go for and who to supply and then who to award the work to. The job should take no more than two weeks, from the tank being available.

[SteveHall]

At least you have found the issue, and good luck getting the boat fixed - shame its this time of year as the season starts.

Id be interested if you have any photos of the tank when removed to show the damage.

[Hf500]

Having just done this ... I would recommend stainless steel but it won't be cheap. I guess it will depend on how long you expect your boat to last/plan to keep it etc

[Wightdiver]

Originally Posted by Andy0

The latest is that the tank does not hold pressure and so it has failed. The job is now to remove the deck and replace the tank and refit the deck. We have invited quotes. Ribeye can do it but the lead-time for the tank is prohibitedly long as this would come from overseas. The decision now is what material to go for and who to supply and then who to award the work to. The job should take no more than two weeks, from the tank being available.

Have you tried Tektanks, based in Hampshire they have a wide range of sizes in stock which can be collected.

[Andy0]

Originally Posted by Wightdiver

Have you tried Tektanks, based in Hampshire they have a wide range of sizes in stock which can be collected.

Thanks for the recommendation, Tektanks are high on our list of options, especially as they are on our doorstep.

[Andy0]

[Crosshouse RIBS]

Originally Posted by Hf500

Having just done this ... I would recommend stainless steel but it won't be cheap. I guess it will depend on how long you expect your boat to last/plan to keep it etc

Do you mind me asking why stainless over Ali or Plastic?

[Hf500]

Now I may have been wrongly advised on this but ... my company bought a 7.5m rib 8-9 years ago which at the time came fitted with plastic tanks. I was advised that they were acceptable at the time. We had a fairly significant failure with one of the tanks and were very fortunate not to go bang ( we carry appx 450l ) The surveyor we use advised us that plastic tanks were no longer recommended and the manufacturer no longer fit them.
The boat is used commercially and for some fairly strenuous work up to F8 although fortunately rarely that bad.
I am not a boat builder nor a surveyor ( I'm not too bad at driving but that's my limit ) and I am learning lots on here. My tuppence worth is from the surveyor / manufacturer that stainless is the safest way to go.
I doubt it is the cheapest that's for sure. Perhaps I was given bad advice...
I am more than happy to learn more and hear from experts. I'm just glad I didn't go bang :o)

[Hf500]

Ps we have another boat with stainless tanks that have caused no problems but that could be coincidence

[gtflash]

Originally Posted by Andy0

Thanks for the recommendation, Tektanks are high on our list of options, especially as they are on our doorstep.

I do believe tek tanks aren't so good with petrol tanks. I once went there to collect some stuff and they really didn't want to comment on petrol as their knowledge base is primarily diesel for fuel.

[beerbelly]

I don't know if its related but I had an aprillia motrorbike with a plastic tank and the ever increasing amount of bio in the fuel we buy was causing the tank to swell its a known problem .mine had the tank off the bike for 3 weeks was half full and when I tried to re fit it the mounting holes were quarter of an inch out . maybe this is why there not recommending plastic tanks

[Hf500]

Interesting, our engine guy ( who is a genius ) advised us to avoid certain fuel outlets as they put so much bio into their fuel. He has experienced about a 400% increase in carburettor problems in recent years that he attributes to it. ( I think it was carbs ) We did keep using it on bigger boats with twin 150's as apparently the filter in the big engines protects it.
I wonder if that affected the fuel tank or not. Like I say , I'm far from a boat builder but interested in learning more

[Crosshouse RIBS]

Originally Posted by Hf500

Now I may have been wrongly advised on this but ... my company bought a 7.5m rib 8-9 years ago which at the time came fitted with plastic tanks. I was advised that they were acceptable at the time. We had a fairly significant failure with one of the tanks and were very fortunate not to go bang ( we carry appx 450l ) :o)

Thanks for answering mel i'm glad you didn't go bang .
Did the plastic tank split? and was the boat made to commercial specs with plastic tanks in and how big were they. I

Originally Posted by Hf500

The surveyor we use advised us that plastic tanks were no longer recommended and the manufacturer no longer fit them.
The boat is used commercially and for some fairly strenuous work up to F8 although fortunately rarely that bad.o)

I never knew of any commercial manufacturers that fitted plastic tanks on new craft. My knowledge however is not comprehensive can you tell mewhat make of RIB it was?

Originally Posted by Hf500

I am not a boat builder nor a surveyor ( I'm not too bad at driving but that's my limit ) and I am learning lots on here. My tuppence worth is from the surveyor / manufacturer that stainless is the safest way to go.
I doubt it is the cheapest that's for sure. Perhaps I was given bad advice...
I am more than happy to learn more and hear from experts. I'm just glad I didn't go bang :o)

No point in paying a surveyor and not taking his advice (nothing wrong with stainless) any idea why the Surveyor didn't recommend Ali which I think lasts longer and takes a hit better. re the price if your having the tank fabbed up then Stainless probably is the cheapest way to go


Stainless tanks aren't a problem but they have a life span which is shortened by the quality of the Stainless, the quality of the media used to weld the tank together and its grounding and shock cushioning when installed. Same goes for Ali the difference for me is whilst both materials go brittle with time Stainless does it quicker. Sounds like your tanks are only 65 and 12 in dog years so you should be alright for a while

Having been a commercial boat driver for twenty years I wouldn't want to be out in a force 8 with passengers or cargo on a Rib. That must'a been some mighty interesting risk assessment meeting that that sanctioned force 8 operation: I'm just joshing sometimes you do get caught out trying to go that extra mile fair winds to you whistling:

[Crosshouse RIBS]

Originally Posted by Hf500

Interesting, our engine guy ( who is a genius ) advised us to avoid certain fuel outlets as they put so much bio into their fuel. He has experienced about a 400% increase in carburettor problems in recent years that he attributes to it. ( I think it was carbs ) We did keep using it on bigger boats with twin 150's as apparently the filter in the big engines protects it.
I wonder if that affected the fuel tank or not. Like I say , I'm far from a boat builder but interested in learning more

yep the Bio has stuff in it that gets through the filter. You need to run 10 u in your water seperators

heres a link that explains the ethanol (bio) issues its an infomercial but it gets the info out first

https://www.youtube.com/watch?v=J9fhxliwj_U