Brine Shrimp Catamaran

Discussion in 'Multihulls' started by kelldog, Aug 8, 2017.

  1. kelldog
    Joined: Jun 2009
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    Location: Bakersfield, CA

    kelldog Junior Member

    Hello Everyone,
    I just purchased a Catamaran that was designed by Thomas Firth Jones. I would ask him the questions that I have but he is no longer with us. So the next source is this forum as I know there are many knowledgeable people here who may answer a few questions. The design is a 23.4 Brine Shrimp. The one I just acquired was built in 2000 by Shelby Craghead. I am not sure if he is around now.

    Question 1; I would like to lengthen the hulls by 3 feet to 27.4 feet. Where would be the place to insert the 3 feet? The section just before the aft beam? The section forward of the forward beam? Or, right in the middle of the hull/cabin.

    Question 2; Mast height per design is 27 feet long. (I have the plans that came with the boat.) Would I need a taller mast? (I think so)

    I have known of this boat since 2005 and Have seen it for sale over the years. It has lived a few lives. [​IMG] I have read Mr. Jones books and he is respected in the multihull community for his contributions to the affordable multihull self-build genre. I look forward to any feedback on my questions. I know this is not the "norm".

    Thank you,
    Kelly
     
  2. cavalier mk2
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    cavalier mk2 Senior Member

    I just replied on your cruising forum post. Right in the middle is my vote and I'd think about adding a mizzen instead of a rerig.
     
  3. kelldog
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    kelldog Junior Member

    Thank you Cavalier,
    I saw that you replied. I prefer a sloop rig. I don't plan on making any changes to the length for the next 6 months to a year since I want to get her in shape to go sailing. Have a few minor repairs to do first. It's been awhile since I had my own boat so I'll enjoy getting her in sailing shape.
     
  4. cavalier mk2
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    cavalier mk2 Senior Member

    I have drawings somewhere I'll try to look it up. You might get by with a taller mast and extended boom but if you want to keep the same rig proportions it means relocating a beam or adding another beam and a Wharram style mast case to span them and put the new rig where you want it. This also means new mast, rig sails etc... while a mizzen is relatively cheap. Your call, always best to sail it first and see what grows on you.
     
  5. kelldog
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    kelldog Junior Member

    Yes, I want to sail the boat as it was designed for awhile and learn the characteristics of the boat. My sailing grounds are Southern CA. I can't wait to be sailing over to Catalina.
     
  6. cavalier mk2
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    cavalier mk2 Senior Member

    If you don't have one a used light weight larger genoa will help for not much money.
     
  7. jamez
    Joined: Feb 2007
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    jamez Senior Member

    I was thinking of building a Tiki 26 a decade or so ago and corresponded with TFJ about the BS (ha) as an alternative. Stll have the study prints. i like the approach to trailing but am unsure how practical it would have been. Can yours fold or was it built with solid beams? Do you have a reason for wanting to extend the hulls? IMO just sail it. Buy a bigger boat if you need more space.
     
  8. redreuben
    Joined: Jan 2009
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    Location: Beaconsfield Western Australia

    redreuben redreuben

    I am with jamez, why didn't you buy a 27' boat ? Don't want be doom and gloom but sounds like good money after bad. 27' hulls from a 24' will feel like 2 sewer pipes. I have a couple of his books, I like his attitude.
     
  9. kelldog
    Joined: Jun 2009
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    kelldog Junior Member

    Of course, buying a larger boat is the logical thing to do. I was looking for a 28-30 foot Trimaran but the two that popped up in my area disappeared. This one came up on the market so I went for it! I am not concerned with the hulls being too narrow after increasing the hull length. I'll be out on the cockpit the majority of the time. The extension would also extend the cabin. I am not in a rush to do any changes right away. First priority is to do some minor repairs and get it on the water to sail. Maybe after a good sailing season I will tackle the modification. My boat folds for trailering. I have the complete plans and an extra sheet was included to build it without the folding option with solid beams. TFG mentions that if the boat is not built to fold then it can be wider. I am looking to increase the length to add payload. If I do this down the road, I will also widen the deck with fixed beams. Maybe. However, being able to trailer the boat opens up a lot of sailing ground.
     
  10. cavalier mk2
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    cavalier mk2 Senior Member

    By the center I should say at the point of maximum hull beam and depth which looks to be either just forward or aft of the daggerboard. There are a couple ways to do it. If long term set up room is a problem you can build the center section as a module separately with each end having a ring frame to attach to ring frames at the ends of the bow and stern structures, Of course you want to bridge the joint at the keel and gunnels, where the main structural elements cross. The other way is to cut the hull and set up the whole thing in the correct location on the strongback all at once. In either case if the new center frame is slightly wider and deeper and the ends match the old center the section will flow into the bow and stern without a flat spot to the curves..

    It is more work than finding another boat but less than building from scratch.
     
  11. kelldog
    Joined: Jun 2009
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    kelldog Junior Member

    Well, I have my little cat unfolded an parked in my parking area. Heh heh.. looks like a mini boat yard! I am starting a dagger board case repair at the bottom of the hull. small leak. The hull opening is 1 1/8 wide and roughly 18 long. I need to sand or grind up into the case to get it ready for epoxy/glass repair. Not easy to get up in there at least 4+ inches to take the bottom paint off down to the existing glass or wood

    Any ideas?

    I did use a grinder to try and get some paint off.. not that effective. I've attached a couple of pics of the boat
     

    Attached Files:

  12. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    What do you expect to get by lengthening the boat?
    From what I see you haven't sailed it yet - how do you know you need 3 more feet?

    Right in the middle is the only place to add length, any other place will distort the hull, messing up the water flow. Of course this causes lots of other change making this the worst place for total work.
    Lots of times, replacing the sails with new will provide enough increase in performance you "probably" won't need a bigger sail plan.
    Or you could move the jib bridle forward, increasing jib size, and then changing the main to a square top sail. Cheaper than a new mast and rigging, along with new sails.
    Bigger might mean better performance in light conditions, but too much power in heavier conditions.
     
  13. cavalier mk2
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    cavalier mk2 Senior Member

    I put my slot tool suggestions on cruisers forum.
     
  14. kelldog
    Joined: Jun 2009
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    kelldog Junior Member

    Upchurchmr,
    Thanks for your input,
    As I mentioned, I have no plans to lengthen the hulls in the near future. I want to sail the boat as designed to get a feel for it and enjoy sailing time. Then maybe.. maybe..after I know the boats characteristics I can decide. I agree that adding length to the middle is the best way to go, but I'm not rushing it. Especially since I have started sanding on the bottom of the hull/daggerboard case. I am going to sand the whole boat for painting. A LOT of work for me.... As for mast and sails.. The wooden mast was broken when the last owner had the boat. I'll need a new one. 27 ft. according to plans. I'll be looking for a used aluminum mast. The sails are in very good condition though.
     

  15. kelldog
    Joined: Jun 2009
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    Location: Bakersfield, CA

    kelldog Junior Member

    Cavalier,
    Thanks! I saw your post. Reciprocating saw look like a winner! I did glue a sheet of 60 grit around a 1 x 1/2 x 24 piece of wood and that worked pretty good. I just need to put together 3 or 4 of those to use and that should get me to the point of epoxy glass stage.
     
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