Forgot password

Bond sheet plywood to sheet steel?

  • 28 Mar 2018 19:19
    Quote
    Reply # 6004558 on 6004237
    Deleted user
    Darren Bos wrote:
    Nicholas Head wrote:
    The hinges and catches will have to be drilled and bolted to the steel. Is there a trade trick so can I stop metal filings from dropping all over the place and rusting? At least I won't need to resort to welding!
    If you stick a couple of rare earth magnets immediately under where you are drilling, they will catch most of the swarf from drilling, it never hurts to have an old towel laid below as well.   When you drill the holes for the latches (and hinges if used and depending on orientation) it is also worthwhile to have someone sit or stand on the lid while you do it.  This compresses the gasket and has several benefits.  You get a better seal, and since the latch now has tension on it when closed, it will not rattle annoyingly when you are motoring.

    There has got to be a way to work some welding into this project :-)  The cockpit drains could be done very nicely with couple of pieces of pipe welded at both ends.  Simple and copletely bomb-proof.

    I see. Yes, thank you Darren and David for those ideas. Obvious now you say it but not to a numpty like me. I will use those hints for sure. I can see the attraction of a welded pipe drain solution. Something like this below?  And then just need to find a competant welder in Cardiff somewhere in the Bristol channel to attach them. I am so glad I asked for help on this. I have learned a lot and can proceed with some confidence of a good result. Thank you again.
    1 file
    Last modified: 28 Mar 2018 19:43 | Deleted user
  • 28 Mar 2018 16:17
    Quote
    Reply # 6004237 on 6003801
    Anonymous member
    Nicholas Head wrote:
    The hinges and catches will have to be drilled and bolted to the steel. Is there a trade trick so can I stop metal filings from dropping all over the place and rusting? At least I won't need to resort to welding!
    If you stick a couple of rare earth magnets immediately under where you are drilling, they will catch most of the swarf from drilling, it never hurts to have an old towel laid below as well.   When you drill the holes for the latches (and hinges if used and depending on orientation) it is also worthwhile to have someone sit or stand on the lid while you do it.  This compresses the gasket and has several benefits.  You get a better seal, and since the latch now has tension on it when closed, it will not rattle annoyingly when you are motoring.

    There has got to be a way to work some welding into this project :-)  The cockpit drains could be done very nicely with couple of pieces of pipe welded at both ends.  Simple and completely bomb-proof.

    Last modified: 28 Mar 2018 16:17 | Anonymous member
  • 28 Mar 2018 12:43
    Quote
    Reply # 6003827 on 6003820
    Anonymous member
    Nicholas Head wrote:Something like 110mm plastic drainage pipe from two openings low down on the back face of the footwell? The nice floor drain in the picture turned on its side, screwed and sealed with sikaflex. At the transom the pipe terminated with an external flange screwed and sealed from the outside. A flap valve required to prevent back flooding in a following sea?
    Yes, I think you're on the right track there, though the flap valve isn't necessary - on Tystie, and on most raceboats nowadays, the transom is open. You should only get minor flooding, not enough to cover the teak grating. Any grating should be as open as possible, not to inhibit the flow.

    I do wonder whether it would be easier to get someone to weld in a piece of tube, with three parallel 6mm stainless steel rods, 25mm apart, welded across the opening to keep the sheets and halyards from disappearing.
  • 28 Mar 2018 11:56
    Quote
    Reply # 6003820 on 6003660
    Deleted user
    David Tyler wrote:

    I don't think the cockpit is excessively vulnerable to being filled by a wave, but I don't see any large drains in case it is. I'd like to put in two very large tubes from the cockpit out through the transom (4in dia wouldn't be too big). The bridgedeck is high, so no vulnerability there. A deep cockpit feels safe at sea, so I wouldn't want to fill it in, and it doesn't look as if you need extra stowage space with boxes within it. I think it will be seaworthy, if it can be made to drain fast enough.



    Thank you for this advice David. I am reassured that Somerled can be seaworthy for my ambitions at least.

    Drains...

    Something like 110mm plastic drainage pipe from two openings low down on the back face of the footwell? The nice floor drain in the picture turned on its side, screwed and sealed with sikaflex. At the transom the pipe terminated with an external flange screwed and sealed from the outside. A flap valve required to prevent back flooding in a following sea?
    1 file
  • 28 Mar 2018 11:43
    Quote
    Reply # 6003801 on 6003693
    Deleted user
    David Thatcher wrote:
    David Tyler wrote:

    I can see all the photos.

    I see a fairly low upstand around the openings, but no lower than is found in all the aluminium forehatches for sale. These have an upstand that presses into a soft rubber seal in the underside of the hatch, which is compressed when the hatch is dogged down, so this is what I would try to recreate in Somerled's cockpit. I like the general design concept, with the steelwork sloping so that it sheds water and the hatch having wedges to support horizontal slats for sitting on. I think I would do the same again, with the addition of the rubber seals. To close them, I'd use some over-centre catches like this.


    My thoughts exactly when I looked at your photos. A good soft rubber seal and with the hatch lidsecurely latched down should fix the problem. On the aluminium ferries I drive we have access hatches which sit flush with the deck. The hatch opening has an inner lip and on the underside of the hatch lid is a soft rubber seal which sits down on top of the raised lip, and then the hatch is securely dogged down. We wash those decks with a pressure hose twice a day and the hatches never leak.

    If you use a fairly soft rubber seal up to even 12mm thickness it should cope with any irregularities in the hatch coaming height.

    h  Thank you both for that. I think I can make new lids to match the one I did previously but with a double coaming and the rubber seal between to stop it deforming. The hinges and catches will have to be drilled and bolted to the steel. Is there a trade trick so can I stop metal filings from dropping all over the place and rusting? At least I won't need to resort to welding!
  • 28 Mar 2018 10:09
    Quote
    Reply # 6003699 on 6003660
    Anonymous member
    David Tyler wrote:

    ... that presses into a soft rubber seal in the underside of the hatch ...

    Something like this would do.
  • 28 Mar 2018 09:33
    Quote
    Reply # 6003693 on 6003660
    Deleted user
    David Tyler wrote:

    I can see all the photos.

    I see a fairly low upstand around the openings, but no lower than is found in all the aluminium forehatches for sale. These have an upstand that presses into a soft rubber seal in the underside of the hatch, which is compressed when the hatch is dogged down, so this is what I would try to recreate in Somerled's cockpit. I like the general design concept, with the steelwork sloping so that it sheds water and the hatch having wedges to support horizontal slats for sitting on. I think I would do the same again, with the addition of the rubber seals. To close them, I'd use some over-centre catches like this.


    My thoughts exactly when I looked at your photos. A good soft rubber seal and with the hatch lidsecurely latched down should fix the problem. On the aluminium ferries I drive we have access hatches which sit flush with the deck. The hatch opening has an inner lip and on the underside of the hatch lid is a soft rubber seal which sits down on top of the raised lip, and then the hatch is securely dogged down. We wash those decks with a pressure hose twice a day and the hatches never leak.

    If you use a fairly soft rubber seal up to even 12mm thickness it should cope with any irregularities in the hatch coaming height.

    Last modified: 28 Mar 2018 10:02 | Deleted user
  • 28 Mar 2018 09:08
    Quote
    Reply # 6003660 on 5995742
    Anonymous member

    I can see all the photos.

    I see a fairly low upstand around the openings, but no lower than is found in all the aluminium forehatches for sale. These have an upstand that presses into a soft rubber seal in the underside of the hatch, which is compressed when the hatch is dogged down, so this is what I would try to recreate in Somerled's cockpit. I like the general design concept, with the steelwork sloping so that it sheds water and the hatch having wedges to support horizontal slats for sitting on. I think I would do the same again, with the addition of the rubber seals. To close them, I'd use some over-centre catches like this.

    I don't think the cockpit is excessively vulnerable to being filled by a wave, but I don't see any large drains in case it is. I'd like to put in two very large tubes from the cockpit out through the transom (4in dia wouldn't be too big). The bridgedeck is high, so no vulnerability there. A deep cockpit feels safe at sea, so I wouldn't want to fill it in, and it doesn't look as if you need extra stowage space with boxes within it. I think it will be seaworthy, if it can be made to drain fast enough.
  • 28 Mar 2018 08:31
    Quote
    Reply # 6003657 on 5995742
    Deleted user

    It seems I made an error in uploading photos that no one else can see. This is a link to a view of the cockpit that is in my photo album. I hope it works?
  • 28 Mar 2018 07:51
    Quote
    Reply # 6003634 on 6003189
    Deleted user
    Paul Thompson wrote:

    I cannot speak for the past but now days when a plywood deck or coachroof is put on, the flange to which it is bolted is 316 stainless steel. However, we are talking mild steel here and for that I will stand by what I've already said

    s  Paul, I am now convinced that my original idea to "ply line" the cockpit is a bad one. It looks like my choice is either to replace the existing lids with more of the same and try to gasket them and find a way to secure the closure. Access is needed for batteries, and locker contents so would still need to be easily opened. Or  a full on conversion of the cockpit to large aft deck. This does appeal but I must admit to being clueless as to hiw to actually build such a deck safe and strong. Thanks, Nick
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

                                                              Site contents © the Junk Rig Association and/or individual authors

Powered by Wild Apricot Membership Software