78 22 FF New Gas Tank Install

[Curious]

Getting ready to install the new tank:



Dry fit:



The old and the new:



I'll have to trim the rear tabs down about 3/8":

[Curious]

Planning to stay true to the Pascoe method and use the mounting tabs on top for extra insurance.  My plastic strips are PVC lattice from Lowes.  They are 1/4" thick x 1 1/2" wide.  What is the general consensus, three strips?



Or four?



Pascoe says "1/4 inch strips of plastic about 2 inches wide and spaced about every 12 inches."   With three they are spaced about 8 3/4 inches apart and with four they are about 5 1/2 inches apart so I thnk I'm ok with three.  The only issue is the base of the tank coffin isn't perfectly flat- it bows down a little in the middle.  What do you guys think?
Thanks, Dan

[Capt. Bob]

You need to keep the tank as dry as possible.

Let air get around the tank to help dry out the compartment on a warm day.

Make sure your deck plates seal well. Remove them (when docked in yard) when weather permits to aid in moisture removal.

Caulk the cover seams better than anything else.  

Keeping water out is what allows a tank to last. Trapped water = corrosion.

I'd put 4 strips more for support than anything else. Again, seal the strip edges good so water can't get underneath between the tank and plastic.

Some members add a drain hole. Mine is completely sealed but has a removable drain plug. The WAC is a different setup, tank wise.

Good luck.

[jdupree]

My coffin has a small hole in the rear to allow water to escape.

Congrats on the tank, it looks great

[wingtime]

Butter up the bottom of the strips with 5200 so there is no air pockets between them and the tank.  Make sure you cut them shorter than the length of the tank so they don't protrude past the edges of the tank.  This way any water that runs down the sides of the tank can't get on top of the strips and make it's way between them and the tank.  My coffin had a drain hole in the aft end.  No matter how well you seal it up water will get in there... so you want to make sure it can get out.  Here is a pic of the strips getting glued onto the bottom of my tank.  



Looks like your doing a great job!

[Curious]

I put a drain hole in the rear of the tank coffin that I can access from the deck hatch near my transom.  I sized it so one of those rubber expanding plugs fits so I can leave it open or plug it.  There is also an inspection port over the sending unit.  On nice days I can open both and get some air flow.  I'm even thinking of opening up an area in the front of the tank coffin to make the fill and vent hose removal/install easier so there would be even more air flow.

[seabob4]

EVERYONE is correct in stating that water will get into the tank compartment, regardless of the measures you take to try and ensure it doesn't.  What I see a lot is water pooling on top of the tanks...most likely at the sender and fill pies.  To be honest with you, whether you use a pry-out, twist-out, or any type of pie that has a removable center cap, they all seem to leak no matter what the manufacturer says.  I would recommend the solid pies that screw down with NO removable cap, that way you can get a SERIOUS bedding job going and it WON'T leak.  Like this Jim Black model...http://store.gotohmg.com/products/6%22- ... Cover.html

[wingtime]

The majority of the water I have seen in the tank coffin is from condensation.  I had the pie plates with the clear cover and I could see the water condesing on the bottom of it. ( actually my 170 still has it)  So what I do is remove the cover when the boat is under cover to allow it to air out.  Two different schools of thought. Whichever one you choose is up to you since both are good ideas.

[Curious]

Hmmm,
Food for thought.  Also, do I need one at the fill and vent hoses?  There isn't one there now.  Thanks for the replies, guys.  

Also, what's the consensus, 3 or 4 strips?  I'm leaning towards 4 for extra support and since the bottom of the coffin has a slight sag in the middle.

[randy56100]

looks good man. whats up with that old tank if u dont mind me asking? looks a lil rough but is it leaking? and are you planning on getting rid of it?

[gran398]

Go with four, since they are not very tall.

Definitely put drain passageways in the coffin, fore and aft. If you can get her inside in the winter...open up the hatches and she'll dry out good

[Curious]

looks good man. whats up with that old tank if u dont mind me asking? looks a lil rough but is it leaking? and are you planning on getting rid of it?

I never ran the boat with the old tank in it, but it was encased in saturated, nasty wet foam.  The area around the sending unit was so compromised that the screws stripped out.  There are pretty significant pits from crevice corrosion all over the tank.  Initially I thought about attacking it with JB Weld and fixing the threads for the sending unit but the more people I spoke to the more I realized that I might fix three or four of the obvious pits, get the tank reinstalled and then spring another leak in a different spot.  I just decided to abandon the whole idea and go with the new tank.  I haven't really thought about what I'm planning to do with the old tank other than use it for scrap sheet aluminum or sell it as scrap.

[Curious]

Some progress.

I lightly scuffed up the surface of the tank bottom where my plastic strips will go with 100 grit sandpaper just to give the 5200 something to bite.  Did the same with both sides of the plastic strips.  Then I wiped everything down with acetone and moved the tank into my basement.  It's still too cold in the garage but the basement is 50-52 degrees.  The minimum temp on the 5200 label is 40 degrees:



Taped off the areas where the strips will go and dry fit the strips:



Next I applied a thick bead of the 5200 onto the tank between the taped off areas and used a plastic spreader to spread it out so most of the surface between the tape strips was covered with a layer of the stuff.  This part was a pain in the a$$ because the 5200 is so thick and with the low temp it was really hard to spread.  Then I tried to butter up one side of the plastic strips before placing them into the 5200 on the tank.  Squished the strip down, rolled it out with a hard rubber roller, ran my finger around the edges to even out where it was sqeezing out.  I tried to keep it as clean as possible but that stuff is difficult to work with.  Ended up getting it all over myself.  After a while I ended up with a pretty decent, uniform bead of it squishing out from under the plastic strips.  I taped down the ends and put some weights on it while it sets up because there were high spots where the baffles are and low spots in the valleys between the baffles.  I figured some weight would help makes sure the plastic strips don't end up lifting in the valleys.





Now I gotta just wait while the 5200 sets up.  A few days anyways, which is ok because I've got plenty to do with trying to get the old hoses out and prepping the coffin for the new tank.

[Capt. Bob]

I'm curious Dan.
What will you use to work out with now?

Looks good but remember,
This is probably the last time any of us will ever see your tank bottom again.

Good luck.

[gran398]

Beautiful job right there Dan

I know about that 5200...it goes EVERYWHERE. Probably contributed to one of my divorces

One of them "Clean Freaks".