Catamaran trampoline

Discussion in 'Multihulls' started by jimmi, Feb 20, 2008.

  1. Meanz Beanz
    Joined: Jun 2007
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    Location: Lower East ?

    Meanz Beanz Boom Doom Gloom Boom

    Can't say for certian but yes looks to be a dead ringer from the photos.
     
  2. waikikin
    Joined: Jan 2006
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    Location: Australia

    waikikin Senior Member

    Meanz, I thought you where leaving a trail of spray but maybe.... smoke! All the best from Jeff.
     
  3. Nordic Cat
    Joined: Jan 2008
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    Location: South of Copenhagen, Denmark

    Nordic Cat Senior Member

    I have found 2 sorces of netting, one in France (in french) and one in the US.

    See here:

    http://www.france-trampoline.com/catamaran/toiles.php

    http://www.multihullnets.com/product/productmesh.htm

    Ask for a sample before ordering, as some of the meshes are slippery when wet!

    I personally prefer a 15-200 welded style net or webbing with double stitching and good UV protection on both sides so it can be flipped after 5 years.

    Regards

    Alan
     
  4. jimmi
    Joined: Feb 2008
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    Location: auckland

    jimmi Junior Member

    Thanks Alan-excellent links
     
  5. Meanz Beanz
    Joined: Jun 2007
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    Meanz Beanz Boom Doom Gloom Boom

    Cheech and Chong blazing down the bay on a Seawind 24 :D Now that'd be a sight.

    OFF TOPIC!

    Sorry!
     
  6. Meanz Beanz
    Joined: Jun 2007
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    Location: Lower East ?

    Meanz Beanz Boom Doom Gloom Boom

    From Nordics links...

    [​IMG]

    Thats about the size of it.
     
  7. tspeer
    Joined: Feb 2002
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    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    Here is one of the Dyneema nets I made for my tri.

    [​IMG]

    The netting is knotless Dyneema with 1" cells, the bolt rope is Amsteel Blue, the stitching is 16 strand ultra-high molecular weight polyethylene, and the lacing is 24 strand UHMW polyethylene - all from Net-Systems. If you're ever in the Seattle area, I recommend visiting them on Bainbridge Island. They gladly took me around their facility and showed me the circular looms where they braid the nets - fascinating!

    Here is a detail of the edge of the net.
    [​IMG]
    I folded the netting over the bolt rope, and stitched it with two rows of running clove hitches at the net intersections.

    On my tri, the outer edge of the tramp is laced to a steel cable inside a pvc tube. The cable is shackled to pad eyes on the ama near the beam-attachment bulkheads, and there's a padeye in the middle as well. I chose to orient the bars of the net diagonally for several reasons.

    The first is it resulted in much less scrap. The netting comes off the loom 100 cells wide, with the cells completely collapsed. You pull the netting out to the desired width. The manufactured width was an almost perfect fit to the length of my tramps with square cells.

    The second reason is because with the cells oriented as diamonds, the lacing at the amas pull on the nets on the bias. Nearly every edge has bars that connect to the outer edge. So tension on the lacings there tighten the entire net. I don't have to painstakingly go around to all the edges to tighten the net, and in fact I have all three solid edges (hull, beams) laced tight to their attachments.

    On the old nets, the 2" nylon netting was frayed and broken at the center pad eyes, indicating that was a location of high stress. For the new nets, I brought the bolt rope out into the netting at the center pad eye, forming a "spider" that distributes the concentrated stress out into the net. Both Amsteel Blue and Dyneema are subject to initial stretching, so this also made it possible to adjust the relative size of the bolt rope, should that be necessary.
    [​IMG]
    The two spiders cross the cells at a 2:1 ratio (two cells inboard for every cell longitudinal), which splayed them out nicely and provided the opportunity to lash them to the netting at frequent intervals.

    I don't have much experience with bare skin against the nets, yet, (I understand people in some locations actually sail barefoot, but in Puget Sound, it's more of a theoretical concept) but the lack of knots and closer cell spacing feel pretty good to the touch so far.

    Dyneema has several times the UV resistance as nylon, and far less stretch. It costs about five times as much. But the longer life and firmness make it a good choice in terms of value for the money. The previous nylon nets lasted 8 years in the South Texas sun, so these may well last for the lifetime that I'll be sailing the boat.

    One caution: The lower stretch of Dyneema means the loads on attachment points can be much higher than for nylon. So take that into consideration when you design the means of attachment of the nets.
     
  8. Meanz Beanz
    Joined: Jun 2007
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    Location: Lower East ?

    Meanz Beanz Boom Doom Gloom Boom

    Eeeeeek ! sailing in shoes :eek: only if I have to :rolleyes: that sounds like no bikini weather, not sure my crew would do that :D
     
  9. Nordic Cat
    Joined: Jan 2008
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    Location: South of Copenhagen, Denmark

    Nordic Cat Senior Member

    Thanks for the good information Tom. I especially like the idea with the spiders to distribute the loads. On my cat, the area where anchor handling takes place is always the first to wear out. I'll reinforce it like you have as soon as the temperature gets better. You've done a really nice job that should last a good many years.

    Regards

    Alan
     
  10. tspeer
    Joined: Feb 2002
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    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    Thanks.

    I have to confess that the choice of Amsteel Blue for the bolt rope was because the color was such a great match to the blue and white colors of the rest of the boat, and because Net Systems was selling it for what thought I might have paid for polyester elsewhere.

    As for sailing in bikinis, I don't really have the figure for them. And the water temperature in Puget Sound is 50 deg F (10 C) all year around, so it's usually boots and foulies all the time - even if it's not raining, there's cold spray if there's wind. Drifting around in the summer, though, the nets are great for catching rays!
     
  11. catsketcher
    Joined: Mar 2006
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    Location: Australia

    catsketcher Senior Member

    10 degrees man!

    Hello Tom,

    My estimation of you has increased even more. We sometimes get water down to 13 degrees in the coldest of winter. We call this spanner water as it feels like someone is using a spanner on your nuts.

    Us Aussies are pretty wimpy when it comes to cold. I have sailed in Hobart (5 degrees in the morning) during winter. I couldn't talk properly after capsizing but we had heaps of fun. Locals had dry suits - we had wet suits. Local sailors tried (and succeeded) in psyching us out by wearing shorts and Tee shirt during the briefing.

    Make sure your nets are strong seems like a good policy. I will show myself as a goose by offering the story below. It seems relevant for cold water sailors.

    I was 22 and just got my new Twiggy tri (back in 1989) My girlfriend's family (now my wife - you know marry the perfect crew) was with us on a winters day. On our way home after a picnic they sat on the leeward wing net. It was attched to the boat by small sail slugs - thin ones you would use on a small trailer sailer. About three had already broken at one end. In my youthful ignorance I thought "Lots more there , no worries"

    A mate then steps onto the area of net with the broken slides and breaks another one then Ziiiiiiiiiiiiiip. Two of Deb's family end up in the water and then another two make it up the hanging net and onto the boat. The extra weight of the family provided enough force to propagate the "tear".

    I got them back on board and happily they all laughed about it but the weather was fine and inshore. Rob James had died in 1983 when his net had broken. If you have a look at his book and look at the nets on Colt Cars - the boat he fell from, you will see the net looks very flimsy.

    So my procedure now is - husky slides if a track is used and no broken slides allowed. Better to use glassed on attachments. Renew net when it starts looking frayed and for me and I understand reasons to differ but I use a bloody strong net. Only four people max when sailing per net and I know this sounds strange but I try not to use them under motor. I will walk on them but not doze or allow the kids to with the motor going.

    Funnily enough in our 3 years cruising in the tropics we only slept on the nets once. The airflow into our bed was really good and we had no mossies inside. During the day we usually tried to keep out of the Sun so we didn't lie around on them either. I mostly used the nets for foredeck work and like to be able to tie the kite bag and such onto the net. Sometimes I have to tie a sailboard down but that can get tough on the net and is only done as a quick measure. A weekend sailor may use a net much differently from us.

    cheers

    Phil Thompson
     
  12. captainjsw
    Joined: Sep 2005
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    Location: Perth Western Australia

    captainjsw Junior Member

    I used 8mm or was it 6mm braid and wove them together. Well not exactly wove them together more like threaded them in and out of each other - you can easily do it yourself - waves just travel straight through, can be repaired anywhere in the world - the spacing is around 50mm I think
    John
     

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  13. scsailor
    Joined: Oct 2009
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    Location: Southern California

    scsailor New Member

    to Tom Speer

    Tom, what twine size/diameter did you use? Does Net Systems have a minimum length order? I need an aft net for my cat. . .

    Thanks
     
  14. mikereed100
    Joined: Jan 2007
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    Location: Borneo/California

    mikereed100 Junior Member

    scsailor,

    If you are in SoCal a good option is West Coast Netting.
    http://www.westcoastnetting.com/raw_woven.cfm
    No minimum order. Two 9' x 9' sections of heavy poly 1.5" woven mesh with UV coating for my boat was $100 with shipping. There is no minimum with Net Systems either, but Dyneema will run about 10x the cost of poly.

    Mike
     

  15. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    for SALE, Black Poly Mesh

    I have a roll of the black poly mesh for sale if someone is interested. We used type material for our small cats as well as the Firefly tri.
     

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