Lets Talk Trailer Bunk Placement...

Discussion in 'Sunfish Talk' started by brianZ71, Mar 4, 2012.

  1. brianZ71

    brianZ71 Member

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    I've done quite a bit of searching and have found many different opinions on trailer bunk placement. What is the consensus nowadays? The three most popular ideas i'm seeing:

    1.) Traditional boat style bunks running front to back, placed out under the chines. boat sits on the wide side of a 2x4

    [​IMG]

    2.) Trailex style bunks that go sideways under each side of the boat

    [​IMG]

    3.) Cut a couple of 2x10's to match the curve of the bottom of the boat

    [​IMG]


    I'm leaning towards #1. Opinions? Experiences?
     
  2. danpal

    danpal Active Member

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    I like a variation on option #1 which takes a little more work but I think it provides better support. It's a contoured bunk design that I found on the Sunfish Sailor Yahoo site. John Howard provides a whole photo essay on how to build it under "Skylarkmk1s Trailer" in the photos section. I've used it for 2 years and really like it.


    [​IMG]
     
  3. tag

    tag my2fish

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    nice timing! I currently have my trailer set up like picture #1 - the bunks were originally set up to close to the center of the boat, but I moved them further out closer to the edges.

    but, I was thinking about switching over to a system more like picture #3 - but instead of just using a 2x10, I'll attach a 1x4 or 2x4 on top of the scribed 2x10, to give a wider bunk surface that still follows the profile of the boat.

    part of my reason for the switch is to make the perpendicular 2x10 boards extend out so that I can add a vertical post up and the option to put a 2nd set of bunks on for carrying 2 Sunfish at a time.

    any thoughts on padding under the bunk carpet? I thought I've seen people use thin foam for extra cushioning.

    cheers,
    tag
     
  4. Wavedancer

    Wavedancer Upside down? Staff Member

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  5. Geophizz

    Geophizz Member

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    I used John Howard's design, and it looks very similar to Danpal's design above. I've read that you should always support the Sunfish at its chines, as that is structurally the strongest location. There is very little internal structure or support inside a Sunfish, almost none actually, so any bump the trailer hits will translate into flexing of the bottom of the hull. Those flexing effects can cause the foam blocks to come loose, and eventually can cause structural weakness in the hull that manifests itself as the "oil can" sound that older hulls can make when riding over waves. If you're mainly a cruising sailor, it won't affect you, but it's the death knell of a racing boat.

    Since I've built my bunks I've seen a lot of trailers from higher level Sunfish racers, and they almost to a person carry theirs upside down, but that really hampers your ability to sail solo.
     
  6. brianZ71

    brianZ71 Member

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    Yeah I hauled mine upside down in the back of my truck last season. It was tough as I mostly sail solo, but I made due. I definitely want to go right side up now that I have a trailer. I'm liking John howards design. That may be a winner.
     
  7. Light and Variable Winds

    Light and Variable Winds Well-Known Member

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    I agree with your selection, but I "car-top" my Sunfish, so I can only reply in theory. ;)

    Having acquired a Sunfish with loosened internal blocks, I'd wish for a trailer that supported the Sunfish as though it were on water. (Or as though I were to trailer :oops: an egg). Working backwards from The Ideal Support, I'd want a hammock, bunk-bed mattress, or a net of nylon strapping; admittedly, none of those are practical, but most trailers are over-built for ~140 pounds, and regardless of what you load on your trailer, every pothole and speedbump will hammer the loadtwice. :eek:

    If one is going to use wood, I'd go for John Howard's design, but with 1x's all around, or pressure-treated 5/4s. "Yes" to cushioning—but strap the Sunfish down tightly, so that the cushioning is fully compressed.

    JMHO—just based on my "loosey-goosey-egg" theory. :) FWIW...:rolleyes:
     
  8. brianZ71

    brianZ71 Member

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    Yeah, and I'm using an 18' boat trailer for this. It was sprung way heavy, but i took apart the leaf packs and am just using the main leaf. The trailer itself is pretty heavy, so it's pretty soft now. I may even go so far as to weld on some small boxes with scrap steel and add a couple bags of sand or something. I've got an ad on craigslist looking to trade this for a jetski trailer or the like, but this will work for now.

    edit: the trailer is 18' overall. Not made for an 18' boat.

    My plan is to pad the bunks and strap it down tightly so that it bounces with the trailer. I've tossed around the idea of putting the bunks on some sort of springs, like the cab on a big rig, but I think that would unnecessarily complicate things.
     
  9. douglas_zargham

    douglas_zargham Member

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    a couple years back i made my trailer into a double decker for sunfish #2. in doing so i cut a 2x into four 2' carpeted pieces and split them over four brackets. each bunk pivots around a single bolt and nylon nut which allows it to conform to the hull of the fish...would work with a single trailer too.
     

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  10. RomanSailer

    RomanSailer Member

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    I spent a bunch of time trying to pattern and cut bunks, crossways and lengthways for my sunfish, and decided there has got to be simpler way. Knowing that the chines are at the strongest point, I decided to concentrate there. What I ended up with is two 2X4 that run across the trailer. On the end of each I attached an upside down U-shaped saddle of 2X4 pieces, spaced to be right under the chine. By doing one at a time, I could get optimal contact and angle, using a through bolt and woodscrew to lock in place. Padded each one and viola. And for longer term storage I just turn the boat over on the same blocks and pads. I can also just pull off the thwart-wise 2X4s and use the trailer for other things (the Old Town or the Laser or a pile of 2xX lumber)
     
  11. tag

    tag my2fish

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    can you post some pictures?
     
  12. RomanSailer

    RomanSailer Member

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    It took awhile to get computer time (teenagers!) but these are the saddles I use on crosswise 2X4 . you can see the thru bolt, which I placed above center to give more support and less chance to split. Once I got the tilt right, I put in a screw to lock it in place. And I had to notch the middle of the crosspiece to accommodate the center keel and keep center of gravity low. In the photo, the boat is upside down for the winter, with heavy plastic cover sheet, but when right side up, it sets right at the chine.
    IMG_2127.jpg IMG_2126.jpg
     
  13. Light and Variable Winds

    Light and Variable Winds Well-Known Member

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    • There are some spring-loaded steel shock-absorbing "isolators" that are discarded after shipping "ride-sensitive" equipment. They are about 2" tall, with a 3" base, and attach using four screws, with a single threaded hole at the top. I have a few, but you'd need a couple-dozen to isolate one 130-pound Sunfish.

    • Some axles on cars have a diagonally-placed shock absorber. I cartop my Sunfish, but I'd try mounting an automobile shock absorber diagonally on any trailer "over-sprung" for the 130-pound Sunfish.
     
  14. Zrtsixx

    Zrtsixx Member

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    I also liked the John Howard set up. I placed the bunks over as far as could on the trailer and used a treated 2"x6"x8'. I used the compass method to trace the cuts on the bunks. In retrospect, I would have used 2"x8" though. I did not cut the bunks at an angle, but I figured out an alternative. The clearance between the hull and the supports under the trailer was about an inch. It seemed a little too tight for me. So I cut some other pieces to lift up the bunks. When I screwed them into the bottom of the bunks, I noticed that the outer frame of the trailer was a little higher than cross rails. By placing the cut wood on the outer rail, it caused the bunk to lean in to the center of the trailer a little ways. Plus, the bunk is resting on the extra piece of wood between the forward cross rail and the out side rail towards the front of the trailer. It is far from perfect, but I think it will do! Trailer lift 2.jpg View attachment 8084
     
  15. Zrtsixx

    Zrtsixx Member

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    Trailer lift 1.jpg
     
  16. bill_k

    bill_k New Member

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    As far as padding for the bunks, I found some above ground pool padding that goes under the pool liner. It is very condensed and holds its shape very well. I've had it on my bunks for 3 years and it still looks great. I used large washers with the screws to hold it to the wooden bunks and then wrapped the outdoor carpeting around the bunks.
     
  17. ssshield

    ssshield Member

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    [​IMG]

    I really like this one. I'm using an old 1969 Dolphin sailboat trailer I restored for my sunfish. It doesn't support the bottom very well though, so I'm going to build a second deck on it to hold the Sunfish, then I can trailer both.

    And of course, I'm sure you've seen this:

    http://www.sunfishforum.com/content.php?pg=trailers
     
  18. vela

    vela New Member

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    Did you finish these with anything?
    I have a support made out of 2x4's and am wondering if boiled linseed oil might be a good idea.
     

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  19. Pat75

    Pat75 Member

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    Why not use a sling like some of the dollies do? Does anyone do this?
     
  20. RomanSailer

    RomanSailer Member

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    I did not use any finish. I would use whatever is at hand. Poly if thined well is a good choice. tung oil. linseed. sikens, if its laying around. My experience is that if you treat the wood, the treatment will last about two years, so you have to re-apply, and the project will last about 10. If you do nothing, it will last about eight years. By which time I want to do something else anyway.
     

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