Diesel tank leaking ( it's not, but what's the chances?)

I have no idea how big your rib tankage is, I suspect smallish in which case agreed a smallish box shouldnt have to endure much flex.

A tank in an F43 will be 100-150 gallon, possibly an odd shape to fit the hull .

If road transported 1/2 full it will rupture the first time the lorry driver bounces a curve.

They're 75 gallons each. If they're baffled and installed correctly then they can't flex.
 
Actually removed through the floor of the flybridge?
This sound incredibly difficult and expensive!!


Yes on the P41, the flybridge floor has a removable section in the centre and the floorboards and supporting ribs in the saloon all come out. Still not an easy job which takes its toll on the interior no matter how careful you are. Incredibly worrying when an engine is being lifted out and manouvered into position to go through the hatch whilst you are in the engine room guiding it, because if it were to fall ???????
Trying to reseal the flybridge floor section after the event took several attempts and continuous removal of the headlining before I finally stopped it leaking. The crane had to be ordered three times as the engines and old tanks came out on the first occasion. The old tanks were used as patterns and the new tanks went in some weeks later followed by the engines some weeks after that. Expensive? yes very, and whilst the engines are out there is little point in putting them back in with old mounts, old battery feed cables, old hoses, pipes etc etc. So it just got worse. I have a much better condition boat now though and (due to our age) rarely go above hull speed so I hope the stainless tanks dont have too much stress.
 
Some interesting posts, but everyone has seemed to forget that manufacturers work to a quality/price compromise.

Stainless tanks are fine if the right quality of stainless steel is used and this is crucial; most manufacturers compromise on the quality of stainless steel.

Aluminium are also fine if correctly treated.

All tanks need the correct isntallation and support which is often lacking.

If we take a look at all tanks (fuel, holding, and water) we can make a few improvements by checking the above points, if they are incorrectly supported than add more support to prevent excessive flexing.
If theres a concern about contamination from debris or electrolytic reaction this can also be dealt with by using the correct epoxy coating. To apply this you need access to the inside of the tank, and the ability to drain it, simply drain it off and thoroughly clean it and degrease it. Do not skimp on this.

Mix the two pack epoxy and pour into the tank and slosh around, I prefer to use a stiff yard brush cut down to fit inside the tank, and paint this compound up the sides of the tank until its all covered. Much the same applies to holding and water tanks, but use a food grade epoxy for water tanks.
This effectively seals aluminium tanks from the effects of diesel bug additives and electrolytic reaction from dropped metal bolts and fixings into the tank. It does pretty much the same with stainless tanks, and works just as well with mild steel tanks, and being a structural epoxy means it gives some additional stiffness.
 
I have a Sealine 310, I have been told that my tanks are breaking down inside which is causing no end of problems. Has any body changes tanks on a 310 fly or can anyone offer any advice.
 
Instead of replying to a 10 year old thread I suggest you start a new one
Ask on the Sealine forum where there may be some experience. I expect new slightly smaller tanks might be a good idea so as to allow fitting via the cabin , therefore avoiding engine removal.
Sealine Forum
 
"I have a Sealine 310, I have been told that my tanks are breaking down inside which is causing no end of problems. Has any body changes tanks on a 310 fly or can anyone offer any advice. "

......in your new thread a few details would be helpful, going to guess you are on outdrives which should make any tank removal repair a lot easier .
It usually only requires moving engines in shaftdrive boats.
Several folks on here have suffered from fuel and water tank failures made from stainless, aluminium and steel. Some tanks are moulded from glassfibre and bonded in as part of the hull.
One of my boats had aluminium tank which corroded at the bottom. Loads of pin holes.
Only practical course of action was to cut and grind tank out of the hull and get complete new bottom on to tank by a local welding company
It proved to be inexpensive and a quick fix compared to getting new tank made up.
 
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Roy @seastoke note the preponderance of Sealine's involved here. I thought this might cheer you up. I have a Sawsall and angle grinder aboard when you need them though (y)
 
Only ever used "plastic" tanks to replace steel fresh water tanks that had failed along the welded seams, a real pain to get at and out as under the side decks on a old Princess.
Had to cut the old tanks into sections with a grinder to remove.
Plastic tanks are much cheaper, plus have the added advantage of less weight and are "flexible" when being persuaded to go into a restricted space.
Found it cheaper to get a custom built tank to my dimensions** with all the outlets where and of the size I needed than to buy a ready made tank.
** Ebay.
 
We had to change our tanks on our F43 as per spottydogs post,yes we had been caught out in some big seas,both tanks went within 7days of each other,when tanks were removed(by me as unable to find anyone who had done a f43 before)they had been made out of aluminium and were larger than the standard size,problem was the baffles were too far apart,had new ones made with extra baffles,all in all not an easy job, one of the hardest jobs is removing the fixed furniture,when thats removed floor comes up and cross bearers removed,tanks can be lifted out,
Hi dj43, we are in the process of trying to access the diesels tank on a f43, are you able to give guidance on how to remove the saloon sofa to gain access, any advice would be much appreciated
 
Hi dj43, we are in the process of trying to access the diesels tank on a f43, are you able to give guidance on how to remove the saloon sofa to gain access, any advice would be much appreciated

I have had a look back but unfortunately not many photos to help you, you will need to remove the control casing for the throttles and any surrounding covers ,back of seat, the settee is made in two pieces and is very tight to remove, I recall having to leaver it out after removing everything around it, I don’t remember it being hard to refit, and once out ,remove flooring and cross timber bracing and the tank can be up ended and pulled out, I managed this on my own, if you do the other side, to remove furniture you will need to access the wardrobe in the aft cabin as there are fixings in the wall that need to be removed,hope this helps but after 12 years job to remember
 
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