Chain Locker Design

Discussion in 'Boatbuilding' started by SeaJay, Feb 6, 2011.

  1. SeaJay
    Joined: Jun 2007
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    Location: Sacramento

    SeaJay Senior Member

    I could use some input / suggestions regarding chain locker design for the 46 ft. motorsailer I have under construction.

    I plan to carry 150 ft. of 3/8” chain (225 lb) and with a plum bow; the chain rests right at the DW and pretty far forward. In theory, I’d like to have a “shelf” high enough above the waterline so that the chain could drain directly overboard, but I’m hesitant to start raising this weight. It doesn’t seem wise to put a drain and relatively inaccessible seacock maybe a foot above the waterline but raising the “shelf” and drain up to a more protected height really starts moving the weight in the wrong direction. Maybe I’m over-thinking the problem but I’d be very interested in hearing how others have dealt with this issue.

    Best Regards,

    Sea Jay
     
  2. tunnels

    tunnels Previous Member

    This is a good place to use Kevlar , Its the ideal material to use in the construction plus Vinylester resinand if you gel coat the inside add 400 grit carborunduim powder and some silica sand . This will fortifyand make the gel coat very wear resistant . Theses are the best of the material i can draw on for what you have in mind . as for a design need pictures and photos to see what and where you intend !!
    :idea::p:D:p
     
  3. mark775

    mark775 Guest

    Well, that was nothing to do with what he asked and strange advice anyway!
    To address the advice and be done with it, one doesn't want wear resistant but easily cleanable. Kevlar here is silly. Years and years of constant anchoring will finally wear through gelcoat - then one splashes some more in there. This area should be as smooth and clean as can be. Certainly don't want the galvanization wearing off of the chain on sharp bits in the gelcoat any more than it already will be on the seabed.
    As to the design of the locker: The forefoot has relatively little volume anyway. You are certainly not raising the center of the mass of the chain by the same distance you are raising the bottom of the locker. I would put the drain one foot up from the designed waterline, forget a valve (I think one foot might be the delineation for needing a valve in ABS rules), build a shelf as beefy as anthing on your boat (You do not want this breaking as the chain lits after becoming airborn), and the net effect is that you raise the mass just a few inches from its minimum, assuming any flare in the hull. If you do put a valve, run the line through a thru-bulkhead penetration and valve where you can get at it. Personally, I would just drain with no valve and concentrate my efforts on making sure that the bulkhead is extra stout and glassed water resistant.
     
  4. Landlubber
    Joined: Jun 2007
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    Location: Brisbane

    Landlubber Senior Member

    ...yep as Mark says and add two drains not one, on each side of the bow, a small ss cowl over the outside prevents water being forced in. No valves, no hoses either.

    Yes and keep the insides very smooth at allow easy cleaning. The celcoat will last many years before redoing. Add a small light to the top, and don't forget the anchor winch is also in this locker, so allow a shefl to protect the undersides of the winch too. try to get the solenoid out of here, inside the fwd berth up high and concealed but readily accessible. Use lanoline grease on the winch all over and the wire cables ends too.
     
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  5. SeaJay
    Joined: Jun 2007
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    Location: Sacramento

    SeaJay Senior Member

    Thanks Guys! As usual, plenty of helpful info to point me in the right direction.

    Just to clarify for Tunnels, the hull is complete and it just so happens that is is constructed of Kevlar and vinylester. However, by the time I get the bulkheads and other structural elements completed in this area, the inside will pretty much be an epoxy surface. I'll pay attention to see that the surfaces are smooth and clean.

    I like the idea of a drain on each side (w/ cowl) and do intend to "box in" the winch motor and switch to protect it a bit from the wet chain. Thanks again.

    Regards,

    SeaJay
     
  6. mark775

    mark775 Guest

    SeaJay, why the Kevlar? Is it a safety net in the event of collision or are you trying to save weight?
     
  7. wardd
    Joined: Apr 2009
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    Location: usa

    wardd Senior Member

    can you use a thick wall plastic barrel?
     
  8. mark775

    mark775 Guest

    Good idea and it will help quiet things but abrasion just isn't that big of a deal. I anchor up to seven time a day and wearing the galvinization off of the chain is more of a concern than wearing gelcoat where the chain touches.
     
  9. SeaJay
    Joined: Jun 2007
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    Location: Sacramento

    SeaJay Senior Member

    Mark,

    I bought the bare hull (no deck, structure) from a bankrupt builder in Canada. It was designed as a light-weight, go-fast, cruiser. Lots of expensive resin, fabric, and core-cell! It is a Bill Tripp Jr. design and I'm sure he'd choke if he saw what I'm doing...but hey, it's my money and my neck if the damn thing sinks, so I'm having a helluva time just putting it together as it suits me:D

    Wardd,

    I used to sell large diameter high density polyethylene pipe and am thinking about using a short length of maybe 18" diameter (standing on end), to actually contain the chain. The stuff is tough beyond all belief and the insides are slick and non-abrasive. I doubt you would ever wear it out but even so, just sent the pipe to the recycle center and get a new one.
     
  10. mark775

    mark775 Guest

    Are there any more of those hulls? These type of places are great for making good deals. Did you buy from the builder direct or did you buy from some type of expediter? I once bought a bunch of stuff from a handler of the Glacier Bay Catamarans bankruptcy for pennies on the dollar and reselling that is actually what is getting me through this winter!
    Where the plastic sits on the shelf is acually where the most wear will occur. The plastic will never wear but somedays, when the anchor is out, will you be able to remove the plastic for cleaning the locker? These places get really skunky and just firing a hose down there may not be enough.
     
  11. SeaJay
    Joined: Jun 2007
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    Location: Sacramento

    SeaJay Senior Member

    Mark,

    It has been about 5 years since I bought the hull and I don't think there were any others left. I actually bought it from an "expediter" as the bankruptcy was settled before I knew about the hull (found it on e-bay).

    If you have any new pieces of equipment for sale from the Glacier Bay Catamaran sale, let me know, I may be interested.

    Regards,

    SeaJay
     
  12. mark775

    mark775 Guest

    All I have left are some SS work tables and sinks and a storage shed full of fiberglass, mostly in tape form (rolls cut into 8", 16", 24" or whatever) and the real score, about ten 48"(?) rolls of cloth of which any one roll more than payed for my purchase and another two payed for my shipping. It's all in Alaska and shipping is atrocious. Lets see some pictures of your boat!
     
  13. SeaJay
    Joined: Jun 2007
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    Location: Sacramento

    SeaJay Senior Member

    Mark,

    I have issues (technical) with photos but here are a couple of shots. The one outside shows the hull shortly after I arrived in California. The second one is taken from my elevated shop at the rear of the barn where the boat is currently located. I cut out the transom so I could add a swim step as well as facilitate easy access from the shop. I also raised the shear to provide visual balance for a pilot house as well as better headroom forward.

    At this point the engine stringers are in place, the floors under the keel are fabricated and I'm working on the keel. It's still a bit cool for epoxy so I thought I'd get the lead melting out of the way before summer hits. As soon as the keel is done, I'll start in on the bulkheads, beginning up front with the chain locker...hence this current thread.

    Best Regards,

    SeaJay
     

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  14. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    The best chain locker is low down....bottom of the bilge for max chain fall and weight down low. ...the box is shaped like a tall pyramid ...taller the better...with it top cut off. Chain naturally piles in a pyramid shape.

    Some installations drain off water into the bilge...some installations use a double bottom pyramid shape chain locker with a small bilge pump installed in the box itself.
    The easy method to build..is Epoxy Plywood. First coat and laminate...one layer mat, one layer cloth... the entire sheet of ply. Both sides . Cut panels, assemble, epoxy filet and biax tape inside seams. biax tape outside seems. Very fast to build and robust .

    When a yacht gets knocked down the chain can not tumble out of a pyramid shape box...in heavy weather the chain stack in a pyramid box cant heave and tangle.


    150 ft of chain is not enough. 10 times water depth for heavy weather anchorage. 300 ft is more like it.
     
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