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Stringer delamination

  • July 02, 2025 1:28 AM
    Quote
    Message # 13516579
    Anonymous member

    I'm currently replacing the two fuel tanks and three of the water tanks on Nerissa with plastic tanks. The two stringers that run along either side of the fuel tanks sound hollow when tapped. One of these I have accidently cut into when removing the port side fiber glass water tank which was made as part of the hull and the stringer (this was a bit odd as all the other tanks are aluminum). This has revealed the foam core in the stringer. The boat is still in the water at present and I'm unsure what is the best approach from here.

    Has anyone had a similar issue?

    Thanks

    Mark


     
  • July 04, 2025 3:55 AM
    Quote
    Reply # 13517410 on 13516579
    Anonymous member

    Hi Mark,

    I replaced my water and fuel tanks. I designed tanks to go through the 

    companion way. I glassed in new bulkheads and stringers as to fit the 

    new tanks layout.  The original stringers and bulkheads were plywood tabbed in. 

    I used 1/4” aluminum for fuel and 12 g stainless for water. I explored the plastic 

    tanks at the time and didn’t use them because I couldn’t get baffles in them. My

    new tanks have baffles and inspection ports between each baffled compartment. I

    also had 3/4” blocks welded onto the tanks on sides and bottom for stand offs so

    any good air circulation around the tanks. Also it keeps the tanks off the bottom so 

    any moisture or water could easy drain through limber holes. 

    George 

    s/v. W42 Cadence
  • July 04, 2025 6:58 PM
    Quote
    Reply # 13517650 on 13516579
    Anonymous member

    Hi George, thanks for that. I'm presently getting quotes for the new tanks. These will be plastic, all hand welded with baffles and inspection ports. CE certified. Adding on the stand offs sounds like a good idea I'll look into doing that. The old tanks had wooden stand offs mounted to the sides of the well, we also have  1" high  ribs running along the bilge to hold the tank up. The old tanks were all aluminum except for one water tank that was fiber glass (I think this was because the fridge used it as its cooling tank now disused). The fuel tanks developed leaks near the bottom on the sides where muck had built up over time. The water tanks failed from having tap water in that has pitted the walls. 

    The main stringers are fiber glass 2" thick with foam inside. when tapping them they sounded hollow but this I have now found to be the low density foam all the glass is thick and well bonded. I need to clean up the fiber glass where the fiber glass water tank was but other than that it is looking good.

    I'm also looking to leave the bow tank as is, as its going to be hard to replace and does not leak. This tank I'm going to change its function so I can use it as a wash down tank for the deck wash pump so I can also use fresh water. 

    We have six water tanks, I'm replacing three. The bow I intend to leave as above. The aft two I will replace maybe next year. One may get changed to a water maker.

      Cheers

    Mark
  • July 05, 2025 7:46 AM
    Quote
    Reply # 13517699 on 13516579
    Anonymous member

    Hi Mark,

    Our tanks were sitting on the on the ( what I call the upper bildge )

    with no way for any water to run buy. So of course holes developed. 

    I made 3” high stringers and a deck on top of the stringers all glassed to the hull so any 

    water can run through.  Since the bilge is so deep and the redesigned tanks to fit through the companionway, I also made another shelf above that to hold the main tanks. In between that space, I designed a wedge shape tank to fit in that area. All is then gelcoated. Everything is designed to be removable for future owners if needed. 
    One photo shows 3/4” plate welded to sides and bottom of tanks to provide for air circulation.

    Don’t know if plastic tanks are strong enough to sit in standoffs. 

    Good luck. :) Each Westsail is unique to itself.

    Best,

    George


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