1974 Aquasport questions

[AquaNewbie]

My tank is not caked with corrosion.   And there are no gaps between the coffin and the tank.   It is quite secure.   I think I will patch the one hole and fill in the other small divot and pressure test the tank at a low pressure.   Maybe 1 psi or so and see it if holds pressure.

I found a Moeller poly tank that is pretty close but it might be too tall. 
https://www.amazon.com/dp/B000MTI146/_encoding=UTF8?coliid=IV5B5EM1359O&colid=338C9MMBJCY40

Dave

[boatnamesue]

My tank is not caked with corrosion.   And there are no gaps between the coffin and the tank.   It is quite secure.   I think I will patch the one hole and fill in the other small divot and pressure test the tank at a low pressure.   Maybe 1 psi or so and see it if holds pressure.

I found a Moeller poly tank that is pretty close but it might be too tall. 
https://www.amazon.com/dp/B000MTI146/_encoding=UTF8?coliid=IV5B5EM1359O&colid=338C9MMBJCY40

Dave

If your coffin measurements are identical to mine, yes that tank is too tall.  Also, the fuel sender location on that amazon tank is located forward of where your fuel sender access hatch is.  Unless you've altered the location to be far forward. 

You have to account for the height of the fuel inlet elbow, which if I recall correctly has a height 1.5" above top of tank.  Then account for the height of the rubber hose, which is 1/4".  The total height from bottom of coffin to underside of fuel hatch is 9".  And pressure testing tank is to 3psi.

[Capt. Bob]

My tank is not caked with corrosion.   And there are no gaps between the coffin and the tank.   It is quite secure.   I think I will patch the one hole and fill in the other small divot and pressure test the tank at a low pressure.   Maybe 1 psi or so and see it if holds pressure.

You posted this earlier:

The "coffin" that holds the gas tank was full of water that I could see through the plug over the gas gauge.   I pulled the coffin cover and pumped out the water and am letting it dry out".

Where the real corrosion lies is in the areas you cannot see. I would recommend you remove the tank from the coffin and inspect it. You may be surprised at what you find underneath. Still, it's your choice. We have seen countless fuel tanks corroded over the years, all of which have been exposed to water trapped between the tank surface and the coffin.

If you do decide to replace the tank, there are several "known" Aqua suppliers or you may find a local shop that will build you one to your dimensions.

http://www.rdsaluminum.com/
Located in Perry Fla. Supplied the Aquasport/Wellcraft Genmar plant in Bradenton/Sarasota with tanks.

http://alloymetalworks.com/
Located in Farmingdale NY, Phil has supplied Aquasport owners with exact replacement tanks for years. Many members here have one in their hull.

 http://www.floridamarinetanks.com/
They use to be located in Miami Lakes and supplied the Hialeah plant with tanks. If yours is original (a real good reason to replace) it most likely came from FMT. They relocated to Henderson NC.

Good luck.

[Capt. Bob]

Here is what I mean when I state, "it's what you can't see".

This is the top of my 91 WAC tank. This was a factory installed unit (note FMT sticker).



Dirty for sure but once wiped off, there was no visible corrosion on top of the tank.

Tank removed:





None of this was visible until I removed the tank. The "coffin" had water lying in the bottom (you can clearly see the waterline). So you need to ask yourself just how much work you are willing to do to have some peace of mind concerning your boat and its crew standing on top of 30+/- gallons of gasoline.

Oh, and the CCP in the background, I replaced that tank 10 years before this Forum existed. I wished I had known then what I've learned from everyone here.

Good luck.

[AquaNewbie]

Hi guys,

I got into this further today.    I was thinking I would change out the gas gauge and then patch the few spots on the top of the tank and be done with it.

Here is my tank in the coffin...


I pump about 20 gallons of "gas" out of the tank with a carter fuel pump.   The first gallon was a water/oil mix which was white.   After that it began to look like old gas - a dark carmel.


I cut the screws off the gas gauge with a Bosch oscillating tool.   I bought it this summer since I have wanted one for a while.  It worked perfectly to cut off the steel screws without sparks. 


Sanded down the area under the gauge with the same tool..  handy.
Drilled and tapped new holes.    Screwed in the new gauge with the old gasket as it was fine! 
Yes, the gauge is twisted - since empty is not 0 on the gauge.   I'll mark the dial with a sharpie.  I wanted straight up to be half full.


Here is a partial shot of the boat.



I am wondering if this boat has had a transom job done on it in the past?  This looks like a repair or perhaps this was factory finish?? 


After doing the gauge I think it would be foolish for me NOT to pull the tank.    I "think" I can get it out pretty quickly with a drywall saw through the foam..

I am also concerned about hidden corrosion. 

If the tank has more corrosion divots in it I am thinking of sanding it down, washing it with acetone and putting a layer of epoxy on it and then one layer of glass cloth.  That should stop the tank from corroding from the outside.   The inside of the tank looks very clean (aside from some misc sand and light crud)   Nothing that a filter could not catch. 

From what I have seen so far the tank only has one pin hole in the top of the tank.   But...I might find more when I yank the tank. 

[AquaNewbie]

Well... It appears that even epoxy resins have issues with Ethanol in the gas we have today...   :-(

I might have to patch this tank by welding it.   I've done this before on a tractor gas tank that was galvanized.  Actually I soldered that one.

I washed the crap out of the tank with soap and water.   Filled it up with water just below the neck that I replaced and soldered it. 

I could also fill it with Argon and braze it with aluminum brazing rod.    We'll see just how bad it is after I pull the tank.

Dave     

[Capt. Bob]

That tank is toast.
Yank it, measure it and order a new one.

Good luck.

[doug mayer]

Teleflex is now Sea Star. I am grateful for this thread, since I am also getting ready to pull the tank on my Osprey 200.  It looks good, and there are no leaks evident--but it is coming out, the coffin will be cleaned, the hoses and fuel gauge sending unit replaced.  I suggest using the 3M 4000, not only for caulking the coffin lid, but also all the screw holes and deck plates, that in my boat were never caulked at all.  Another choice would be Sudbury Elastomeric compound.

[AquaNewbie]

Well, I'm back at it.   Life got in the way of my boat repairs.

I welded up a new tank which was a project in itself.   Using 1/8" 5052 Aluminum.   I learned a lot doing that and will definitely be doing it again as I have another boat that also needs a tank.
The tank passed a pressure test after a few weld repairs so it is ready to go into the boat after I painted it.

If you guys have any tips on mounting the tank in the coffin, let me know. 
I read this thread already:  https://classicaquasport.com/smf/index.php?topic=14273.msg141575#msg141575

However I'm not sold on using PVC strips and caulk to hold the tank. 

I think that rubber blocks or rubber hose under the tank might be better? 

I'm definitely going to drill the aft end of the coffin with drain holes.  My coffin is currently water/fuel tight which really makes no sense.

This boat will be kept on a trailer, so I can keep the bow lifted, covered, with the drain plug out.

Dave

[Capt. Bob]

However I'm not sold on using PVC strips and caulk to hold the tank. 
I think that rubber blocks or rubber hose under the tank might be better? 
Dave

My mounting is different due to my coffin not being molded into the deck. My tank rest on a glassed in cored (plywood) that is raised over the keel (centerline). This was to allow water to pass from the foward bilge to the stern bilge under the plywood through bulkhead openings at both ends. The tank originally was "cradled" by rubber straps attached to knees which were then attached to the stringers on each side.

That stated, my tank now rests on the plywood base and I attached neoprene strips to the bottom of the tank to give a little cushion between these points. The neoprene is attached to the tank itself with 3M 5200 but NOT to the floor itself. The 5200 fully coats the neoprene thus holding it to the tank surface while at the same time acts as a barrier between the two (rubber/aluminium) in an effort to reduce/eliminate both galvanic and crevis corrosion that could occur on the tank surface at that point. I also bolted aluminium channel to the floor at each end and attached it at the top (see photo). This limits movement fore and aft (tank slide) while also aiding in holding the tank down (assisted by fuel weight). Other members have used straps covered with hose (to prevent chafing). There are several ways to shin this cat.



On my coffin, I sealled off (isolated the foward and stern bilge sections)


 

Again, as always, keeping the coffin as dry as possible with the ability to allow air circulation when in "port" is IMHO the most important element in tank longevity.

Good luck. 

[boatnamesue]

However I'm not sold on using PVC strips and caulk to hold the tank.  I think that rubber blocks or rubber hose under the tank might be better? 

Not caulk...5200...used to adhere the strips to tank, then used to adhere tank to coffin.  It ain't moving.  But this fact presents the 1 future issue...removing the tank.  However, if the tank is prepped appropriately, the tank will likely outlast your ownership of the boat.  Even if you're still not sold on this method, I'd reconsider using rubber.  It corrodes and is porous. 

[mshugg]

However I'm not sold on using PVC strips and caulk to hold the tank. 

I think that rubber blocks or rubber hose under the tank might be better? 

I'm definitely going to drill the aft end of the coffin with drain holes. 

Dave

Your boat, your rules.  Only thing is that any black rubber contains carbon which will cause galvanic corrosion.  Capt Bob used 5200 to create a barrier.  If your rubber is across the tank, it will interfere with water draining and create crevices for corrosion.  Rubber and straps as originally installed by AS will give you a 10-15 year tank, maybe more maybe less. I had to replace the tank on my 1985 170 after only 5, but the factory did a poor job of sealing the coffin, and I didn’t catch it until problems surfaced (Friday boat).

For my CCP rebuild I chose to go with modified Pascal with PVC strips on the bottom and PVC chocks to block it in place.  There’s nothing but 5200 in contact with the tank and no place for water to collect.  There’s plenty of airspace and easy but water proof access to give the tank a fresh water rinse.  Hopefully, I’ll be around to give a report when it fails.



There are many great examples of tank installs here on CAS.  use what makes sense to you.  Bottom line, your boat, your rules.

[Capt. Bob]

Last time.

Whatever material you choose to use in mounting the tank, you need to be sure to create a waterproof barrier between that material and where it comes in contact with the tank. That is the "silver bullet" in preventing corrosion that will occur if water is allowed to get between the two surfaces. This also goes for the tank itself and the coffin. Make sure you have clearance around the tank itself and the box.


I think we beat this mule quite enough.


Good luck.

[AquaNewbie]

I appreciate the replies..  and honestly don't think we are beating a dead mule/horse.  :-)

I can't find that much discussion about gas tank mounting methods period!

However...
My boat is a 1974, making it 45 years old....  I'm 61 now (yeah, I can't believe it either)...    The gas tank likely failed about 5 years ago.. so 40 years of life while it was foamed in. 

This boat has only seen fresh water (Great Lakes). 

So simple math.. 61 yo plus 40 years of gas tank life = 101 years old....

I'm no sure how much boating I will be doing at 101, but it might not be much.    Although my one Great Grandmother did lived by herself until 104 and died at 106... so you never know.

Still, my Grandkids may be using the boat, so I don't want to do a crappy job!   Chances are the hull will still be functional in 40 years, but I might not be.

This is similar to the thoughts I had when I re-roofed my house a few years ago... do I buy 40 year shingles or 50 year shingles.   Or perhaps it doesn't matter!    I went with 40 year shingles. 

Anyway, I like the idea of blocking in the tank with foam blocks and using lengthwise strips on the bottom.

I've used 5200 before and found out that it is really a one time install.  Removing that stuff requires a grinder, etc.   If the tank does spring a leak, I do want to be able to remove it and repair it.  Since I made it out of 1/8 Alum it should take a lot of scuffing before it wears through.  If I block it in, that shouldn't happen.

The tank I pulled out was the original tank and the aluminum was a lot less than 1/8".  I'd guess 0.085 or so.  Too light IMO, but then again, it did last for about 40 years. 

Thanks,  Dave

 

[boatnamesue]

Don’t put the buggy before the horse.  Aluminum doesn’t spontaneously spring leaks w/o causation, such as crevice corrosion.  When you install a tank appropriately it will not leak.