The Pascoe Method- Stabilizing Fuel Tank

[boatnamesue]

Started a new thread in hopes of hearing from those who have utilized the Pascoe method when installing fuel tank.  The article about this method is here:  http://www.yachtsurvey.com/fueltank.htm   I'll be installing a new tank here shortly.  That thread is here:  http://classicaquasport.com/smf/index.php?topic=14273.0

I like the idea of the pvc strips bonded to tank in order to elevate tank from coffin bed.  But what concerns me about bonding the pvc strips to the coffin bed with 5200 is having to remove the tank in the future.  Most of you have likely used 5200 to bond this or that.  For those who have had the fun experience of breaking the 5200 bond, I've felt your pain.  It's a tough task even when you have direct access to the bond.  But how do you break the bond with no access???

If you had to remove the tank you'd have no way of accessing the bottom of the tank to chisel away the 5200 bond.  And since it's bond is so amazing, if you pry the tank straight up you will take off the surface of the coffin bed thats adhering to the pvc strips.  Kinda concerning, right?!

What are some other methods of packing the fuel tank to the coffin?  After removing all of the foam in my fuel coffin there is no way I would use that stuff.  There were pockets everywhere within the foam that was holding fuel residue.

[wingtime]

Most use a modified Pascoe. I did on my 200xf. What I did was bond the strips to the boot of the tank but not to the bottom of the coffin box. To hold the tank in place I used the factory method of straps, but I insulated them from the tank with split vinyl hose. There is a thread of my install.

For the holes from the rigging trough, I just sealed mine up with rope caulk/putty.

[Woodeneye]

^ +1 for Wingtimes method.

[boatnamesue]

There is a thread of my install.

Could you please post the link to your thread.  Your member profile page allows me to only see your posts, not the threads you've started.  And you've got like 200+ pages of posts lol

[Brendanpd28]

http://classicaquasport.com/smf/index.php?topic=4460.msg28118#msg28118

I believe this is wingtimes tank install.



http://classicaquasport.com/smf/index.php?topic=4360.msg27422#msg27422

This is his coffin lid recore.

[wingtime]

Yup that's it! Sorry I didn't have time to look it up this morning. I was a volunteer safety /marine life watch boat for some F1 boat races here in town this weekend.

[Brendanpd28]

I knew you obviously would have responded shortly wingtime. I have a bunch of your threads bookmarked so it was quick and easy lol.

[boatnamesue]

http://classicaquasport.com/smf/index.php?topic=4460.msg28118#msg28118

I believe this is wingtimes tank install.



http://classicaquasport.com/smf/index.php?topic=4360.msg27422#msg27422

This is his coffin lid recore.

Perfect, thanks bud.

[boatnamesue]

To hold the tank in place I used the factory method of straps, but I insulated them from the tank with split vinyl hose.  For the holes from the rigging trough, I just sealed mine up with rope caulk/putty.

I looked through the 2 threads but didn't see or read any info specific to the above^^^.  I could see the hose insulated straps across the tank, which looks awesome btw.  But no pics of the hardware or whatever means you're using to anchor the straps.  If you have some time, please let me know the details of what you did and what you used.  I'm leaning towards this modified method.  Thanks.

[wingtime]

Sorry, I meant I sealed up the hole at the end of my rigging trough on my 170.  so you wouldn't see that in the topics about my 200XF.  I was getting water in the bilge of my 170 and I could not find the source.  Turns out it was the hole in the end of the rigging trough where the wires going to the fuel tank went thru.

[boatnamesue]

Sorry, I meant I sealed up the hole at the end of my rigging trough on my 170.  so you wouldn't see that in the topics about my 200XF.  I was getting water in the bilge of my 170 and I could not find the source.  Turns out it was the hole in the end of the rigging trough where the wires going to the fuel tank went thru.

You must be referring to this:



I experience the exact same issue...water getting in the bilge.  Now I know for certain how it's getting into bilge.  I will also be sealing this hole. 

Aside from that, I'm curious to learn what you used to anchor the insulated straps to the fuel coffin bed.  Assuming the new replacement tank I get will have identical dimensions as the old tank, the width is 20".  The fuel coffin width is 21" at the base, then gradually widens.  So there isn't much space between the coffin wall and fuel tank at the base.  Half inch on each side.  Maybe that's all I'll need to anchor, I dunno. 

[wingtime]

The straps were simply screwed to the coffin sides before the tank was placed into the coffin. This is how the factory did it.

[boatnamesue]

The straps were simply screwed to the coffin sides before the tank was placed into the coffin. This is how the factory did it.

Really, huh.  What were the screws anchored to?  Stringer?  Cause the coffin liner is fairly thin, or at least it looks that way. 

[Capt. Bob]

The straps were simply screwed to the coffin sides before the tank was placed into the coffin. This is how the factory did it.

Really, huh.  What were the screws anchored to?  Stringer?  Cause the coffin liner is fairly thin, or at least it looks that way.

Yes, that's the way they were anchored. With foam "tape" under the straps for chaff protection but....
The foam retained water which lead to corrosion and when you reached a point, the shifting of a full tank would break the corrosion loose. Leaks sprung.

Now you have the opportunity to mount the tank in a far superior way but if you don't keep it dry, it will corrode again so....

First, if you are going the aluminum route, you can have the fabricator weld mounts on the tank. If you find a poly that fits, they usually have some type of mounts and often tie down kits available. You just have to think through what method you'll use. You have a defined space (coffin) and your goal is to keep the tank from shifting. Any number of non-metallic braces can be used. That isn't the hard part really. Again, there are numerous threads showing different methods other members have used.

Mounting aside, your biggest task is sealing the hatch and the deck plate(s) you have. It is the biggest source of water intrusion you have to deal with in replacement of your tank. Silicon caulk isn't the trick here IMHO but rather a sealer/adhesive such as 3M's 4000UV. bedding the hatch and making sure the deck plate is as watertight as possible is the key. I replaced my pop out style plates with screw in and they seem to stay dry. Don't forget the fasteners. They too are a source of water intrusion (rain, wash down). Water runs from bow to stern under the coffin so that isn't a concern (assuming the coffin is sound). Mount the tank so air can get around the surface, keep it from sliding around and seal the access thoroughly and an aluminum tank will last a long time.

Good luck.

[boatnamesue]

First, if you are going the aluminum route, you can have the fabricator weld mounts on the tank.

Mounting aside, your biggest task is sealing the hatch and the deck plate(s) you have. It is the biggest source of water intrusion you have to deal with in replacement of your tank. Silicon caulk isn't the trick here IMHO but rather a sealer/adhesive such as 3M's 4000UV. bedding the hatch and making sure the deck plate is as watertight as possible is the key. I replaced my pop out style plates with screw in and they seem to stay dry. Don't forget the fasteners. They too are a source of water intrusion (rain, wash down). Water runs from bow to stern under the coffin so that isn't a concern (assuming the coffin is sound). Mount the tank so air can get around the surface, keep it from sliding around and seal the access thoroughly and an aluminum tank will last a long time.

Good luck.

Appreciate the insight.  Take a look at the picture here.  I believe the weld mounts you mentioned look like this?  A buddy of mine sent me this picture of how his tank is secured.  He has 4 welded tabs, each using (2) 1/4" screws going thru a small spacer block and into the stringer.  Since my hull is 40 years old, I've been trying to not use the stringers as an anchor support, unless absolutely necessary.  Maybe my thought process here is overkill, I dunno. 

How do you feel about intruding the adjacent stringers in order to secure tank using these weld mounts?