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1984 H31 Water tank top repair

Discussion in 'Mid-Size Boats' started by Reg M, Sep 10, 2016. Add this thread to a FAQ

  1. Reg M

    Reg M

    Joined May 21, 2016
    118 posts, 5 likes
    Hunter 31
    Ca Montague, Prince Edward Island Montague
    IMG_0010.JPG Just started another project on my new to me H31. Somehow during one of the PO's tenur the top of the water tank became cracked and had obviously leaked. The last owner installed a bladder type water tank in the original tank. I got rid of the bladder and am in the process of repairing the tank top. See photos. I have all the sealant removed, I ground the gelcoat off the damaged area and I plan to use a couple of layers of fibreglass cloth, using waxed polyester resin. I realize I will have to sand between coats to get rid of the blush but not a problem, I have a 6 inch Portercable random orbital sander which will take care of that. I will then gelcoat the whole thing on the underside and just the repair on the top side. After that I will sand and polish the gelcoat. The jury is still out on what to use for a sealer when I install the top after completing the repairs, I have no idea what the original installer used. I am leaning toward 3M 4200 but will welcome any advice/experience anyone can offer. Sorry folks, I am struggling with these photos and how to insert them but I'm sure you get the picture (pun intended) Reg
    . IMG_0012.JPG IMG_0011.JPG IMG_0012.JPG IMG_0011.JPG IMG_0012.JPG IMG_0011.JPG
     


  2. woodster

    woodster

    Joined Sep 15, 2009
    6,240 posts, 262 likes
    S2 9.2a
    US Fairhope Al
    there is some kind of coating for potable water tanks that is used to do this not sure what it is but i am sure Peggie Hall or some one will know...its to keep the water safe and clean .......
     


  3. Peggie Hall HeadMistress

    Peggie Hall HeadMistress

    Joined Dec 2, 1997
    6,423 posts, 305 likes
    - -
    US LIttle Rock
    Sorry, don't have the answer to that one. If it were my boat. I'd replace the tank, 'cuz the average life of an aluminum water tank is about 20 years and I'm betting this one is close to that old if not older. The thing about aluminum tanks...the first leak is always only the FIRST leak. It's highly likely you could invest a whole bunch of time effort and $$ into repairing it now, only have it fail somewhere else within a year or two. A top quality rotomolded PE tankfrom Ronco Plastics Ronco Plastics Marine Catalog isn't that expensive and will outlast the boat. Just be sure to specify a water tank when you order it.
     


  4. Reg M

    Reg M

    Joined May 21, 2016
    118 posts, 5 likes
    Hunter 31
    Ca Montague, Prince Edward Island Montague
    The tank is not aluminum, it is gelcoated fibreglass and it is molded right into the boat liner. The top is also gelcoated fibreglass. I want to bring the tank top back to original rather than put in a plastic one which would not be placed in as good a position as the original thus affecting speed/performance. The actual tank is in mint condition, it is only the top that is damaged. I suspect it may have been left full after fall haulout and froze thus expanding and cracking the top. That is the only explanation I can imagine that would damage the top like that. Later on I may install a second tank made of plastic right at the aft end of the quarterberth and only fill it when we are heading out for a week or more thus giving us twice as much potable water.
     


  5. Peggie Hall HeadMistress

    Peggie Hall HeadMistress

    Joined Dec 2, 1997
    6,423 posts, 305 likes
    - -
    US LIttle Rock
    Maybe a dumb idea, maybe not: What if you cut the top completely off and made a new "shoe box lid" cover for it, sealed to the tank with epoxy?
     


  6. Reg M

    Reg M

    Joined May 21, 2016
    118 posts, 5 likes
    Hunter 31
    Ca Montague, Prince Edward Island Montague
    The top is already off, that is the top in the photos. I will take a couple of photos today of the actual tank which should make things more clear. It is not a problem to repair the top following the steps in my original post. My only concern is in using the right product to form the seal between the tank and the top when I put it back on. It fastens down with screws about every six inches. The surface of the tank where the top sits on is nice and smooth but the matching surface of the top is by no means a "machine fit" so I think whatever I use to form the seal will have to be something in a tube rather than a roll of gasket type material. 3M 4200 is the only thing that comes to mind but I am hoping someone else who has had their tank top off will chime in here and let me know what they used and if it was successful.
     


  7. Don Crowther

    Don Crowther

    Joined Sep 4, 2007
    644 posts, 16 likes
    Hunter 34
    CA Elbow, Saskatchwen, Can.
    Reg.
    I would think if you could find a food grade caulking that would be the way to go. Sorry I can't offer an better idea that that.
    Good luck
     


  8. Keith13315

    Keith13315

    Joined Feb 22, 2004
    222 posts, 0 likes
    Hunter H340
    US Michigan City Indiana Michigan City
    I put a bladder type in mine the original did not seem safe to drink. Mine didn't leak it just wasn't the best water and like I said iould never drink it. Now with the bladder it is fresh and safe.
     


  9. kloudie1

    kloudie1

    Joined Nov 6, 2006
    7,375 posts, 300 likes
    Hunter 34
    US Mandeville Louisiana
    The crack should be ground out into a tapered "V" groove and new mat and resin layered in to get the top back to structural strength. This kind of sealant,http://www.lowes.com/pd/DAP-Commerc..._clickID=15421480-8387-4e62-9485-3ac567622857 with the lid correctly prepped, and properly applied will work .. We did a job on a Beany-Toe several years back like that and the sealant is still doing its job. The problem with built in tanks like that is that when the hull flexes, the shape of the tank gets distorted and works the sealant pretty hard..
    Check out this : http://www.westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf
     


  10. Reg M

    Reg M

    Joined May 21, 2016
    118 posts, 5 likes
    Hunter 31
    Ca Montague, Prince Edward Island Montague
    Here is the latest chapter in this saga. On the top I put a layer of woven roven followed by a 2nd coat of resin before it cured, then a layer of fibreglass cloth and 2 coats of resin before the 1st cured. I then sanded that and applied a final coat of resin which also got sanded along with the rest of the top side. I then flipped it over and ground the crack out to a vee which I filled with chopped up fibreglass cloth and resin then, before it cured applied a layer of woven roven and a layer of fibreglass cloth in the same manner as the top except where I had to glass over the reinforcing member and in doing that I usd three layers of cloth. Then sanded the whole bottom side. Next came the gelcoat on the bottom side which, after curing, I sanded to 320 grit. Flipped it back over and gelcoated the top side and sanded to 320 but had some thin areas so I added another coat. I then hand wet sanded that with 320 and then 2000. I could have sanded more and brought it to a shin like original but I would have had to add another coat and it was just not worth the effort for something that is going to live hidden under a mattress. Before I started the sanding of the first coat of gelcoat on the top side I used a jigsaw with a fine blade to recut the inspection port opening I had partially glassed over. I sanded the edge of the hole with a drum sander then while adding the 2nd and 3rd coats I also gelcoated the edge of the hole. Here are the pictures taken throughout the process.

    This shows the crack v'ed out
    IMG_0026.JPG
    IMG_0027.JPG
    1st layer of woven roven on bottom side
    IMG_0028.JPG
    2nd coat of resin on woven roven
    IMG_0029.JPG
    Completed top side
    IMG_0030.JPG
    Completed bottom side
    IMG_0031.JPG

    The next step in this process is to block the 2 inch hole the previous owner made in the wall of the tank to run the fill hose to the bladder tank he installed. I looked around my shop and came up with a 5 in PVC pipe cap which I cut the sides off on my bandsaw leaving me a flat piece of PVC a little less than 5 inches in diameter. I plan to place this on the inside of the tank over the hole but my delema was how to hold it in place while the 3M 4200 cures over a 24 hour period. The inside of the tank is not square so a brace was out of the question. So, I took a short piece of PVC pipe, sanded one end and used crazy glue to stick it to the side of my patch which will face the hole. Prior to gluing it on I drilled a 1/2 in hole all the way through it(see photos). I cut two rectangular pieces of 3/4 inch wood and four wedges. The plan is to apply 4200 then put the patch in place with the PVC glued-on pipe protruding through the hole. I will then put the piece of 7/16 steel rod through the holes in the PVC pipe and using the wood blocks and wedges (2 sets of opposing wedges) thus clamping it in place until the 4200 cures. The piece of PVC pipe can stay there forever. The series of photos should make it a bit clearer. I will post final photos when job is complete. I also plan to install a new fill hose with a new deck fitting which I will install in the deck just forward of the stbd spinaker turning block. I don't like the fill in the lazarette because if it overfills you get water in places where it should not be. Stay tuned.

    IMG_0032.JPG
    IMG_0034.JPG

    IMG_0035.JPG
     

    Attached Files:



    Last edited: Sep 15, 2016
  11. kloudie1

    kloudie1

    Joined Nov 6, 2006
    7,375 posts, 300 likes
    Hunter 34
    US Mandeville Louisiana
    Very good job, Reg !
     


  12. heart of gold

    heart of gold

    Joined Sep 21, 2009
    368 posts, 2 likes
    Hunter 34
    CA Squamish
    For future glassing projects with waxed gelcoat or resin, you can just wipe the the surface with acetone to remove the wax in addition to a light sanding.
     


  13. Steve Dion

    Steve Dion

    Joined Dec 2, 1999
    15,176 posts, 8 likes
    Hunter Vision-36
    US Rio Vista, CA.
    Reg:

    We had issues with our tank leaking from the lid on our H'31. I removed the lid and tried sealing it with sealant, then with buytl rubber but neither worked. We ended up cutting two access ports in the lid. The original lid did NOT have an access port. There is also supposed to be a baffle in the tank to dampen the water movement.

    In the end I determined that the holes that the factory used to secure the lid in place were all oversized. We had the lid glassed in place. You may want to check the archives to see if you can see some of the posts regarding this problem for yourself.
     


  14. Steve Dion

    Steve Dion

    Joined Dec 2, 1999
    15,176 posts, 8 likes
    Hunter Vision-36
    US Rio Vista, CA.
  15. Reg M

    Reg M

    Joined May 21, 2016
    118 posts, 5 likes
    Hunter 31
    Ca Montague, Prince Edward Island Montague
    Very helpful info. I was not aware there was supposed to be a baffle. I will have to give some thought about whether or not to make one or if it is really needed. I have had visitors and other fires to put out so have not progressed further on this project. I note that on SD's post that the fill fitting on the tank is a fibreglass tube which is glassed in place but the other two are thru hulls and this is the same with mine. On the other post the fill is a thru hull like the other fittings. Steve, I have about six screw holes that are enlarged and I was tempted to just drill new ones beside the old ones. Were you able to get the screws down good and tight after filling and re-drilling the holes? I had also considered filling them with west system epoxy with microballons then re-drilling.
     


  16. pateco

    pateco

    Joined Aug 12, 2014
    1,370 posts, 186 likes
    Hunter 31 (1983)
    US Pompano Beach FL
    Mine was glassed in by the PO, but still leaks a little when totally full. Leaks around the access port. Only one access port, so very difficult to clean inside.
     


  17. IH82BL8

    IH82BL8

    Joined Feb 6, 2013
    404 posts, 14 likes
    Hunter 31
    US Deale, MD
    I removed my to reseal it and clean the tank. Use 4200 to re-seal it; DO NOT use 5200 or no will ever be able to remove it again. The access port on mine is near the forward inboard corner. Is it possible that your panel broke because of the location of the port? While you're in there, it's a good time to consider enlarging the supply hose from the tank to the pump.
     


  18. SailormanDan

    SailormanDan

    Joined Jan 24, 2009
    336 posts, 53 likes
    1981 Cherubini Hunter 27
    US Alexandria, VA Belle Haven Marina, VA
    The baffles are there to reduce the wave action/sloshing in the tank while underway. I have pulled the lid on my waste tank and scrubbed it out good before replacing the hoses. My freshwater tank hasn't been use much and is moldy inside so I'm planning on doing that sooner than later.
    I would not glass in the lid for either tanks, in order to be able to pull it in the future if need be, but that may be personal preference. The baffle in the water tank would be impossible to scrub through a 3" inspection post, you'd have to make sure you stay on top of the mildew.
    The repair to the top looks good!:plus:
     


  19. Reg M

    Reg M

    Joined May 21, 2016
    118 posts, 5 likes
    Hunter 31
    Ca Montague, Prince Edward Island Montague
    I have a new baffle under construction and was hoping someone who has had the top off their tank can tell me if there is supposed to be something like battons to hold the baffle in place or is it just jammed in tight to the corners? I am thinking if it is loose it would clunk against the tank sides.
     


  20. IH82BL8

    IH82BL8

    Joined Feb 6, 2013
    404 posts, 14 likes
    Hunter 31
    US Deale, MD
    The baffle is unsecured. It runs from the forward inboard corner to the aft outboard corner. It has a notch of IIRC 2"x6".
     



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