Catamaran nets

Discussion in 'Boatbuilding' started by Charly, Apr 19, 2013.

  1. Charly
    Joined: Dec 2009
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    Location: st simons island ga

    Charly Senior Member

    Hey guys, I am inching closer to the net building process in my build, and just wanted to revive the issue here. I have decided to go with the pvc pipe, glassed to the hull method, with an internal rod inserted that I can lace the net to.

    http://www.boatdesign.net/forums/at...d1357165002-kurt-hughes-daycharter-36-001.jpg

    My cat will probably see a lot of abuse, so I figure I should have a good sturdy system. I found this supplier online, and am considering using a 1" strap, that I can loop over the rod, and then weave criss cross. One continuous piece side to side, and then one continuous fore and aft, with maybe a spectra line attached to a turnbuckle or a cam cleat on the ends for tensioning.

    http://www.uscargocontrol.com/Webbing/Polyester-Cargo-Webbing

    Any comments or ideas appreciated. My main worry so far, is chafe around the edges of the holes in the pipe. Has anyone noticed this as a problem with this method?

    edit. Just poking around on the above site I found these wear sleeves.http://www.uscargocontrol.com/Ratch...Sleeves-for-1-Webbing-Purchase-by-Lineal-Foot they look like just the ticket.
     
  2. messabout
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    messabout Senior Member

    Not clear but it seems that you are going to make a trampoline for your cat. What is wrong with a conventional canvas or coated canvas tramp?
     
  3. keysdisease
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    Location: South Florida USA

    keysdisease Senior Member

    What about mesh Charly? I had that on my McGregor and thought it was a good way to go. I did have the strapping in the most forward tramp. On my boat they were woven diagonally.

    I would think a lot less sewing, and much more durable than you might think. Also gives you a second chance if you drop something on it, with webbing its bye bye

    Steve
     
  4. masalai
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    masalai masalai

    Non knotted net is very comfortable, no knots to create uncomfortable bumps - I used the stuff that the trout-fisheries use to contain their fingerlings until harvest time and has been in for more than 2 years with NO problems. - - Not cheap but far better than all the other options I have seen...
     
  5. keysdisease
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    keysdisease Senior Member

  6. Charly
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    Charly Senior Member

    This is what I had in mind. The photo is of a sister ship.

    I can't tell how this particular one is attached, but if I went with the straps like this one, I guess I would wrap them around a rod insert, which would entail cutting out holes in the pipe that are big enough for the straps to go through, around the rod, and back out. The photo shows a diagonal pattern, which makes sense now I think a little more about it...the spacing between straps would be more even if it was done that way. (and it looks better too)

    In another thread there were complaints about the knotting in nets, if you use fishnet or something, so, as Mas says, it should knot be knotted :D.

    We have a lot of shrimp trawler nets lying around here in my area, but I haven't looked at them closely (yet).

    For me it boils down to strength, price, then weight, stretch, then comfort, then mesh size, in that order.

    I appreciate all input.
     

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  7. groper
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    Location: australia

    groper Senior Member

    Hey charly, what sort of glass scantlings are used to wrap the pvc pipe to the deck? Im gonna go the same way too i think... i was looking at a alum mast section for a forebeam but im going to investigate making an infused, cambered oval section carbon forebeam aswell before i make a decision as i think a have a neat, very simple and quick method for it... ill included the PVC with it once i have an idea of scantlings...

    And yep, im going to look at trawler nets (prawns / shrimp) aswell... its so cheap...
     
  8. Charly
    Joined: Dec 2009
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    Location: st simons island ga

    Charly Senior Member

    Hi Groper, I bogged the sections of pvc (thinwall 3/4") to the sheer and mainstrength beam fairing with phenolic balloons/aerosol/chopped fiber, and resin bog mix, then layed up over that one layer of 12 oz biax and three layers of 10.5oz uni.,w/ warp perpendicular and staggered widths feathered into the hull and deck. I don't have the forward tramp section dimensions handy, but my build is just like the one in the photo above.

    This was "unofficial", seat of the pants, backyard engineering though. Kurt Hughes' plan set does not specify. You might want to run some more serious numbers for your build. It has since occurred to me that the layout for the holes cut into the pipe will have a significant effect on the overall strength.

    Looking forward to learning from your forebeam build
     
  9. Charly
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    Charly Senior Member

    Hi messabout, I haven't ruled out anything yet, so I am open to the idea of solid canvas tramps. This is my first big cat, and I have little experience to go on. I did sail a 36 Macgregor down the keys once though, and I remember how uncomfortable it was sitting crosslegged on the tramp. It was like being on a big Hobie (no offense to Macgregor owners- it was fast and fun, and I have a bad back)

    Anyway, I do like being able to "dig in" and hold on, as with a net or strapping, and There is the uplift windage factor with a solid tramp.
     
  10. WestVanHan
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    WestVanHan Not a Senior Member

    UV resistant or UV proof.
     
  11. Charly
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    Charly Senior Member

    For anyone interested, just stumbled across another source-

    http://www.atninc.com/atn-multihull-nets-sailing-equipment.shtml

    UV may well be an issue with the cargo straps. The site says they are UV resistant... anyone have any direct experience with the straps?

    keysdisease, what kind of material was the strapping on your boat? Was it the vinyl stuff or woven?
     
  12. keysdisease
    Joined: Mar 2006
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    Location: South Florida USA

    keysdisease Senior Member

    I had both. I built a hard deck for the main deck out of balsa cored FG using the roof only of a mold for a 53' Key West work boat.

    The "net" forward of that was the mesh and the little area forward of that was web similar to whats pictured. This was what Sunrise recommended and worked great for me. Both the mesh and the web were cut and sewn diagonally. Both were black and in the Keys the mesh somehow remained comfortable while the web did get hot in the sun. The mesh was surprisingly durable, much more durable than it looked.

    On the MacGregor original were 3 net areas, the smallest being forward of the front crossbeam, the next being between the forward crossbeam and the crossbeam with the mast and the largest being between that beam and the aft beam.

    I stumbled across this while looking for net configurations, might be helpful:

    http://www.net-sys.com/catamaran-netting.php

    Did you sail the MacGregor that worked out of the Caribbean Club in Key Largo? I know that boat pretty well, was owned by Rick White. There was also a MacGregor that worked out of the Marriott resort in Key Largo and yet another in Key West.

    Steve
     

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  13. Charly
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    Charly Senior Member

    It was in '85 or '86. I don't remember much about the boat.... I was working up at ORC with an outfit called "Yacht tenders", and the guy that owned the boat couldn't sail, and wanted me to go with them down the keys. I forgot his name, but he lived up in Homestead. Anyway, the boat was a beast at the dock. He had one big outboard, set way offcenter, and the water was so skinny you couldn't put a board down to help straighten things out. This was up at that marina just west of jewfish ck. bridge on A1A. Once we got through the bridge though, and put the sails up, we hauled ***. We were at Faro Blanco in no time. It was a fun trip! He had those "tractor seats" on it. My back has been out of whack ever since:D

    There was another 36 McGregor up at the reef that never went anywhere (had the masthead float on it) those were the only two I knew of at the time
     
  14. Charly
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    Location: st simons island ga

    Charly Senior Member

    The reasoning must have been that the web material would stand up better to abrasion from the ground tackle, no?

    Was the webbing/strap material woven like the truck cargo strap that I linked to in the OP? (like seat belt material)?
     

  15. keysdisease
    Joined: Mar 2006
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    keysdisease Senior Member

    Similar to seatbelt, but like 3 x as thick Steve
     
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