Fuel Tank Access

Hello all,

I just realized that out of all the boats that I have viewed, that I haven't seen one fuel tank. It didn't occur to me to ask. Out of sight, out of mind.

I was doing some research today trying to figure out where fuel tanks are located. I was shocked to see a bunch of youtube videos with boats ripped apart as the yard cut the tank out.

Is this typical? Are the tanks generally buried and inaccessible? How can they be monitored if so? Why are boats built like this, so the tanks aren't serviceable?

Space is at a premium. We replaced two 350 gallon tanks that were hidden in the sides of the engine room with 4 tanks totaling 440 gallons. The reduction in volume of the tanks allows some visibility of the tanks as there is now fore and aft room to look at the sides of the tanks.

We covered the sidewalls of the tanks with plywood because we needed the wall space to hang all of the engine room equipment.

Marty

The deck filler can be a clue to locating fuel tanks.

I had to remove the engines to replace the fuel tanks. This is likely the norm. Tanks are tucked against the sides or bukheads, then engines and systems are fitted. The old tanks had lasted 30 years, and would have lasted much longer if the engine room vents had not let rain in down the sides of the tanks. I now have drainage on enlarged vents to prevent a repeat.

I decided to repower whilst the engines were out, and also replace a lot of other systems. In the engine room we basically went to bare hull, painted it and then rebuilt. Expensive. But all new systems in a good hull gave me a great outcome. Ive just completed a 1500 nm shakedown cruise in the PNW. No issues of any consequence, a tribute to the Shipwright's CoOp in Port Townsend. Would a new boat have cost less? Maybe. But I dont like the styles of the new ones in the price range.......

GalaxyGirl said:

Is this typical? Are the tanks generally buried and inaccessible? How can they be monitored if so? Why are boats built like this, so the tanks aren't serviceable?

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Can be ugly getting them out on many boats!!

But not on a 38' or 42' Californian aft cabin trawler. The box for the twin double beds in the aft cabin each contains two 125 gal tanks. Lift up the matress and the 3/4" plywood plate and out they come.

The ex-wife never could get used to sleeping on top of 500 gallons on fuel.

Maybe I shouldn't have told her??

When looking at purchasing a boat, seek the ones that are built with proper fiberglass tanks. They will never need to be moved. Only an occasional cleaning though proper access ports.

Sent from my iPad using Trawler

The big hassle is moat boats have a box of fuel , not a proper servicible fuel tank.

This is because new owners do not ask for a fuel tank, and the boat assembler will never spend a buck unless forced to.

You can cut aaccess holes in the tank to clear and repair. I cut a hole big enough to climb into the tank to clean and weld the tank. If the boat is 30+ years old the fuel and tanks are a concern. You can cut the old tanks out but I plan on leaving them and using using them as the frame support for smaller multi tanks.

GalaxyGirl said:

Hello all,

I just realized that out of all the boats that I have viewed, that I haven't seen one fuel tank. It didn't occur to me to ask. Out of sight, out of mind.

I was doing some research today trying to figure out where fuel tanks are located. I was shocked to see a bunch of youtube videos with boats ripped apart as the yard cut the tank out.

Is this typical? Are the tanks generally buried and inaccessible? How can they be monitored if so? Why are boats built like this, so the tanks aren't serviceable?

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A boat as big as you are looking at must have accesible service hatches. Make note of the material the tank is made of and have it well inspected before purchase.

If you are buying a trawler more than 10 years old determine the material of the fuel tanks. Mild steel, very popular in the 80s and 90s has a 20+ year life span. At some point the mild steel tanks will rust out and have to be replaced. This requires removing everything in the engine room and cutting the tanks out.

Generally 20 year old boats with mild steel tanks that have not been replaced will be discounted by the cost of the replacement.

Just did Bay Pelicans in 2012 and the cost was $20,000 plus,

Marty

My plan does not require have to take the engine room or engine apart.The boat with be in running ability and nobody will know see the tanks are being replaced. With three tank replacing one at a time. After plastic comes mild steel the aluminium. If the tanks were taken care of the could last 50+ years. We have tanks in the plant 70+ years and still in good shape. I hoping the tanks last another 10+ years and I would give very little discount as the survey should have that included. If you have a plan its should be no big deal.

May believe is tank last long in colder non humid climates. Also a tank that is used is a happy tank. Use and maintain them and they will last a long time.

Bay Pelican said:

Mild steel, very popular in the 80s and 90s has a 20+ year life span. At some point the mild steel tanks will rust out and have to be replaced.

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As FF said above that's not always so, depends upon how it's designed and installed. My boats 45 year old mild steel tank was removed, cleaned, painted and reinstalled 2 years ago. It will probably still be good when the boat is scrapped.

CPseudonym said:

As FF said above that's not always so, depends upon how it's designed and installed. My boats 45 year old mild steel tank was removed, cleaned, painted and reinstalled 2 years ago. It will probably still be good when the boat is scrapped.

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Agreed...my 26 year old steel tanks were nearly perfect except in a couple spots...some surface rust/bubbling

Just hard to repair when crammed in like they were. But I bet after me fixing the leaks ans some PM they would have lasted another 10-20 years without leaking a drop. Seemed a shame I cut them out...but the room is super!

Edelweiss said:

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The box for the twin double beds in the aft cabin each contains two 125 gal tanks.

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That was clever...

So, what's the best material, stainless steel or fiberglass?

The tanks should be able to be viewed. Is that correct. If they are completely hidden, that's not typical?

Fiberglass by far for diesel use, as long as it is made correctly by a reliable builder. I have heard some issues with certain resins for gasoline use.

I have a 17 year old Hatteras LRC that was made with fiberglass tanks, they are as good as the day they were built.

Sent from my iPad using Trawler

Fiberglass is used by some builders but not many...they do have some good features. For bigger tanks, well done steel is hard to beat for ruggedness, ease of modification and cost. Aluminum is probably the next most common. Small boats can get by with poly tanks but no reason large custom ones couldn't be made or even aleady installed by the PO. Stainless isn't all that common in larger tanks due to costs...but some are out there.

The problem I have with SS tanks is there are a dozen mistakes that can be made welding them up that won't manifest themselves until later on. In non marine applications I've seen plenty of shoddy weld practices (that look fine visually) work for a while then prematurely fail. For that reason I'd rather see anything else used except stainless.

Properly designed and installed it would be tough to beat mild steel in the larger sizes IMO.

Is aluminum a good material for the tanks?

GalaxyGirl said:

Is aluminum a good material for the tanks?

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Designed and installed correctly yes. My previous precautions regarding stainless not withstanding there are no inherently "bad" materials IMO.

GalaxyGirl said:

Is aluminum a good material for the tanks?

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I would prefer mild steel over aluminum or SS. Aluminum goes not have a very high corrosive and galvanic value and SS is heavy and hard weld and has to breath. As mentione before multi small plastic is my first choice. The reason aluminum is used its light and easy to weld.

FRP, aluminum, stainless steel, mild steel ... Each of these materials have their own caveats, all are fine if built and installed properly. Now your task is to research proper fuel tank installation.

Many Far East built boats were built with what has improperly been called "Black Iron". I don't know where the name came from, I guess its like "osmosis" and "electrolysis", just a catchy moniker improperly applied 98% of the time. "Black Iron" tanks are actually mild steel with a treatment that makes the steel turn almost black.

Conversely, my single 125gallon aluminum tank is in a most obvious place: right across/below the opening to the rear (lazarette) hatch in the cockpit. It blocks the 36"x36" opening so much that I can only reach an arm into the rear hatch (where the house battery bank resides). It makes accessing things such as the rudder stocks/steering mechanism, rear bilge pump, and rear through-hulls nigh impossible.

I guess that in some boats, in an attempt to cram so much equipment in the engine room, accessibility is compromised.

Fuel tank access

Having suffered failures of both water and fuel tanks on my present boat, I have some pretty strong opinions regarding recreational vessel tankage. For what it's worth, I am attaching an "open letter to the marine industry", which is (perhaps) my way of venting my frustrations regarding this issue. As with all things, your mileage may vary, but here's my $.02.

Pete

jungpeter said:

Having suffered failures of both water and fuel tanks on my present boat, I have some pretty strong opinions regarding recreational vessel tankage. For what it's worth, I am attaching an "open letter to the marine industry", which is (perhaps) my way of venting my frustrations regarding this issue. As with all things, your mileage may vary, but here's my $.02.

Pete

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An excellent letter, I thank you for posting it. I surveyed a boat this morning and each of my eight points of fuel tank inspection were marked ... "Not inspected due to lack of access"

Professional Boatbuilder is an influential magazine read by all boat builders, naval architects and anyone else ivolved in repair, re-fit or new builds. The magazine is free to anyone in the marine business (wink, wink). I suggest you submit your letter to them.

I'd also suggest you send a copy to Mr.John Adey at ABYC. All of the major boat builders are in regular contact with ABYC and many sit on various committees.

GalaxyGirl said:

Is aluminum a good material for the tanks?

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I helped a friend remove the aluminum fuel tanks that failed, from a late 60's, 40' Tolly. Interestingly enough the failure points were all at the lower welded seams on the tanks. It didn't appear that there was any corrosion?
I'm not a metallurgist, but it looked like some sort of stress fracture in the welds. It would have been interesting to know what caused this. The tank company offered to grind out and re-weld the seams. They said the tanks would be as good as new. However the owner elected to replace them with stainless. So I guess we'll never know?

Phil Fill said:

Aluminum goes not have a very high corrosive and galvanic value a.

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Could you explain this.

Marty

jungpeter said:

Having suffered failures of both water and fuel tanks on my present boat, I have some pretty strong opinions regarding recreational vessel tankage. For what it's worth, I am attaching an "open letter to the marine industry", which is (perhaps) my way of venting my frustrations regarding this issue. As with all things, your mileage may vary, but here's my $.02.

Pete

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An excellent letter. I suggest that you submit that to Passagemaker or another boating magazine. With just a little editing, your words would impart some amount of wisdom about the situation to the cruising community at large. In addition to the marine industry, boat owners should know about these issues when viewing prospective boat purchases. And, your comments about engine access/removability are just as important as tankage access/removability.

Bravo, sir, for expressing thoughts that most of us keep pent up.

While I agree production boats are for the most part not maintenance friendly...it's because they sell because they are pretty...not user friendly.

Ask any boat marketing guy what goes on in boat shows and showrooms. The head of marketing in the Northeast for Sea Rays once told me that they would use a $20.00 set of plastic hinges instead of the $50.00 stainless ones if the engine guys said the cost of filters just went up from the engine manufacturer. I said you got to be kidding me. He said nope...people beat up sales guys for dollars much of the time...they say I can get the XXX for $350 cheaper over there ...even though the 2 boats aren't even close in size, design, etc...etc..

The average boat buyer is woefully uneducated and fully expects the seller to warranty much of the boat and will usually have someone else maintain it anyhow. They are NEVER thinking tank replacement at that point.

Granted trawlers should be a different breed when it comes to new boat shopping...but I'll bet that because so many little "nice things" are left out...they are still shaving price points when and where possible. My guess is designing around tank removal is the last thing on their minds. They probably think the tank was well made and they installed it correctly...with "proper" maintenance that tank will outlast several owners..... Used boats that far down the line I seriously doubt affects anyone back in the design teams let alone their ability to convince marketing they should build into the boat those additional costs.