Deck-Hull Joint

Discussion in 'Fiberglass and Composite Boat Building' started by Dutch Peter, Aug 12, 2004.

  1. sail
    Joined: Oct 2009
    Posts: 19
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: China

    sail Junior Member

    Hull-deck joint

    The join was glued all the way round the boat and had no fastenings anywhere at all !! never had one problem with any part of the 8 boats , but i did increase the glueing surfaces from 40mm to 60 to get a little more from what we were doing . :p[/QUOTE]
    I am on my way to build a 7 m cat (see attached files). I would be interested in photos or designs of your Hulll-deck joints you did in Korea.
    I wonder if I could build vertical boat halves and join them. While building I would leave a 50 mm PVC void along the top of each doubled glassed half. I would join the halves with a 100 mm wide glassed foam strip inside, in bedded with an epoxy structural putty, filling the initial 50 mm PVC void and overlapping each side of 50 mm.As a finish I would glass the interior with a 200 mm wide FG tape.This would leave a perfectly seamless joint both from inside and outside. I don't know if it is feasible. What is you opinion on this "theory"?
    Thanks for your advise.
     

    Attached Files:

  2. tunnels

    tunnels Previous Member

    glues for deck joins

    The hull and deck join is the most important part you will ever work on !!
    It has strains and stresses more than you can imagine !!
    One the join need t be wide to get a really good bonding surface
    And second and really important the adhisive need to be semi flexible !
    Epoxxy out of a can with all those secret recipies of powders and potions is really not good enough !!
    The glue is hard and semi brittle .
    West have semi flexable epoxies that you need to use and follow there recipyto the letter .
    The company in nz (Adhesive Technologies )have just such a mix called HPR25 easy to use, easy to mix, has a good work time ,and man does it stick!!
    Its semi flexable ,White in colour and what was used on the 8 Korean match racing 36 foot Yachts . Our hull and deck join was changed from 50 mm to 80 mm and the stern join from 35mm to 65 mm as a safety procaution because they get used like bumper boats , One accident in two years of racing and the join survived but the glass in the gunwhale had to be redone in a small area . The join showed no signs of letting go but the glass where the other boat hit was totalled . After the repaires it was back on the water the same day and the join is still going after 3 years without any sign of dammage what so ever.
    This from my exsperiances and knowledge and the product we used !!
    I have used Plexis and have no doubt to its stickability . I did not like the smell and the work time was way to short for what we were doing .My be we were using the wrong product !
     
  3. sail
    Joined: Oct 2009
    Posts: 19
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: China

    sail Junior Member

    Hi Tunnels
    Thank you for your interesting information.
    In my case, there would be no "hull-deck" joints. It would just be two halves joined in the (vertical) center, like the Ian Farrier F-22 (2 halves construction).This would be a different "load situation" than (hull-deck bonding). In this case the hull structure would be monolithic (sandwich) with no flexible joints.
    P.S:
    China (Sanya) is now also my home.If you come down give a call (look up my e.mail)
     
  4. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    We always Glass the joints on the inside 360 degrees,with these wonder glues remember they are no stronger than the substrate's Peel/shear and in a small area at that.
     
  5. Steve W
    Joined: Jul 2004
    Posts: 1,844
    Likes: 73, Points: 48, Legacy Rep: 608
    Location: Duluth, Minnesota

    Steve W Senior Member

    Tunnels, thanks for the info, just to clarify, is the joint you used just the simple inward turning flange on the hull with the deck sitting on top or something different?
    Steve.
     
  6. Steve W
    Joined: Jul 2004
    Posts: 1,844
    Likes: 73, Points: 48, Legacy Rep: 608
    Location: Duluth, Minnesota

    Steve W Senior Member

    Hey Sail,thats a cool little cat,who is the designer? got any details to share? Hope those rudders can be made to kick up. The join you are planning has been used by Richard Pilkington in NZ on the Great Barrier Express and Turrissimos since the early 70s. I dont know how he dealt with joining the outside laminate, not an issue with a custom but a cosmetic problem on a female molded part, you system sound feasible, you would still have a small gelcoat repair but minor. I would try to pick Pilkingtons brain.
    Steve.
     
  7. sail
    Joined: Oct 2009
    Posts: 19
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: China

    sail Junior Member

    No problems sharing.
    We operate a sailboat (6.3 m trimarans) renting business from the beach in China (no marinas). One can go out in flat seas (with 5 guests on board) and come back to the beach in 2 m waves,rudder and centerboard up..better be a good helmsman. Security was a very serious concern. This is why I designed this new cat with a keel (see attached file) and side rudders, to facilitate boarding from the rear. As guests, we can have children, pregnant woman and old people. In China, regarding Foreigners, their is NO ROOM FOR ACCIDENTS!
    I designed it (CAD files) to answer these very specific "operational" needs. An architect did the details. The rudder will be fixed for the keel version and tilting for the dagger board (sports) one. I would be very interested in sharing "hull-deck joints" information with Richard of NZ.
     

    Attached Files:

  8. Steve W
    Joined: Jul 2004
    Posts: 1,844
    Likes: 73, Points: 48, Legacy Rep: 608
    Location: Duluth, Minnesota

    Steve W Senior Member

    Thanx Sail,very cool. That must be fun what you are doing. About a decade ago i spent 18 months in Taiwan as the engineer for a Taiwanese sporting goods company and on the weekends i would drive 20 kilometers to a book store in Taichung and there was a big open air resturant across the road where i had noticed a flag pole but hadnt taken much notice otherwise but one day i looked closer and thought to myself, hey thats a sailboat mast so i went to take a look and to my suprise there in a pool surrounded by goldfish was about a 40ft well used ex charter catamaran,not bad looking either.
    Steve.
     
  9. sail
    Joined: Oct 2009
    Posts: 19
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: China

    sail Junior Member

    Hi Steve,
    I was the first one to start an exclusively sailboat-renting business in Hainan. 3 years ago many Foreigners told me I was 10-15 years ahead of my time and that it was much too soon to start a sailboat business in China. Now, Downtown Sanya there is a private (High -End) Marina with many Lagoons and Bénéteau 46.,.million $ motor boats (Including NBA Yao Ming's)..just sitting at their docks. Sanya is a huge Bénéteau show case! In a few (short) years, it will become the Chinese French Riveria. Sanya bought the Miss World pageant and It will be one of the stops for the 2012 Volvo race..not bad for a "small" city of 600 000 souls!
     
  10. rxcomposite
    Joined: Jan 2005
    Posts: 2,752
    Likes: 608, Points: 113, Legacy Rep: 1110
    Location: Philippines

    rxcomposite Senior Member

    Hi Sail. You are right. My friend just arrived from China (was working there) and he says economy is booming. Up north, he says, rich ones buys two or three houses, and they like expensive toys. You must have hit the vein right.
     
  11. tunnels

    tunnels Previous Member

    These are some of the details of the deck join area !!
     

    Attached Files:

  12. sail
    Joined: Oct 2009
    Posts: 19
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: China

    sail Junior Member

    Hi Tunnel
    Thanks for your nice and instructive photos.I have seen this joint on Beneteau's 46 downtown Sanya' harbor. It does a VERY NICE JOB since the hull-deck joint is bolted and glued at the same position as the stanchions (200 mm from the edge), leaving a continuous esthetic edge curvature (deck-hull) . As a production boat one would need 3 molds: two sides + partial deck. I think it would be worth it.
    As a one off custom boat, I think taping the joints of the two halves, inside out would be easier and faster. I don't know if any yard uses the vertical boat halves taped method.
     
  13. tunnels

    tunnels Previous Member

    Hi
    The center line taping we used long time ago on Yachts built out of split moulds and glass joined , then a cast iron keel was placed inside and secured in place and then the deck fitted , glued, glassed ,and the wooden belting bolted through and plugged and sanded .
    Stagger the boats laminations well and need to get the best secondary bond its possible to get along each side of your join up .:)
    What kind of resin you looking at using ?? Hand laid or infused ??
    Like i mentioned the thin bow and the burst effect will be two areas for major concern for my way of thinking .
    :confused:
    Hope you have some good all glass ring frames inside the boats to hold there shape !!:D

    Good luck :p
     
  14. sail
    Joined: Oct 2009
    Posts: 19
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: China

    sail Junior Member

    Hi Tunnel
    I will be pleased to meet you in Sanya. Here is my e.mail:
    sanya.sailing@gmail.com
    Give me a call a few days before so I can plan.
     

  15. couch
    Joined: Dec 2010
    Posts: 7
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: NL (Can)

    couch Junior Member

    I used Plexus brand (methacralyte sp?) extensively on a 20m offshore power passenger cat - designed to DNV HSC with High Modulus performing the structural engineering on the project - with great success.
    All the rough destructive testing that we subject the shop prepared samples to seemed to demonstrate that the laminates would fail rather than the adhesive joint - even on finished gel coated surfaces contaminated with wax / pva.

    Best though to have it properly spec'd as there are many factors to ensuring that the join is effective ... plus there are many different formulations for different applications and features (e.g. work time). Smell was a bit nasty as were the potential side effects from prolonged exposure - so don't eat any of it!
     
Loading...
Similar Threads
  1. farmerRob
    Replies:
    24
    Views:
    2,553
  2. bruceb
    Replies:
    10
    Views:
    1,571
  3. Cacciatore
    Replies:
    5
    Views:
    2,422
  4. Southern Cross
    Replies:
    23
    Views:
    8,519
  5. thorhawaii
    Replies:
    1
    Views:
    2,977
  6. Donavan C Marais
    Replies:
    12
    Views:
    2,701
  7. Clive Barry
    Replies:
    2
    Views:
    1,925
  8. hyboats
    Replies:
    30
    Views:
    26,901
  9. therigwelder
    Replies:
    15
    Views:
    6,806
  10. William Dion
    Replies:
    9
    Views:
    4,888
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.