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Thread: seawind 24 hard decks

  1. #61

    Default Polycore Independent Impact Tests

    BORKED

  2. #62

    Default Re: seawind 24 hard decks

    Hey Zed,

    Yes, I also think that Tony used the heavier glass on top to deal with the localised pressures, instead of increasing the stiffness. That brings me on to a related topic of how to finish the topside. I have read of people putting carpet over the top, which would be comfy, but heavy when wet. Others have just painted in anti-slip paint, which would be light, but not so nice to work on. As you do spend a lot of time crawling around on your knees, I think I will miss the tramps from that perspective. I'm thinking of covering the decks with a sheet of foam. Bunnings sell rolls of foam designed for workshops etc, which are approx 4mm thick. This would cushion the local impacts to a degree. Combined with the impact absorbing properties of the honeycomb it may be possible to get away with 400gsm.

    If 400gsm turns out to be too "bendy", Polycore suggested to just put some strips of Uni-directional glass on the bottom. Under-engineering can be fixed, but it would be nice to get it as close as possible first time.

    The offcuts from the 3 sheets I will use to re-do the floors in the hulls. They just haven't stood up to the use over the years and have been repaired already a few times by previous owners. It seems the way they were constructed was just on a layer of cheap 3mm ply with a fibreglass mat over the top. Over the years the ply, unprotected from the bottom, has just disintegrated and floor is too soft. I would like to strip the lot out and replace it with a composite floor.

    I'm not aware of an 8mm core thickness, it is not on the price list they sent me. It goes 4, 6, 10, 12, 15, 19 ... never mind.... I can see that there is an 8mm Honeycomb core size, maybe that is what you saw. 8 would be good to slot into the mast beam. I may have to just bolt a strip of aluminium on, or if I get really confident with my (as of yet non-existent) glassing skills, reduce the core thickness of the leading 25mm to 8mm and put a few extra tapes on.

    I was thinking of keeping the side tracks and sliding the decks into that using some flat aluminium bolted to the side of the decks. I worked out that if I use 12 or 15mm core I can bolt a strip to the top side to slot into the track on the centre console and the front beam. A strip bolted to the bottom will fit into the track along the hull. The back of the deck will then not line up with back beam, but if I make a wedge shape spacer which gets bolted to the top, a strip of alminium on the top of that would finally lock the whole deck into place.

    However, I had not done the maths on the weight of the tracks themselves. I would probably have to add on another 2.5kg each side to account for the above mentioned aluminium & bolts. That would make it 15kg all up to fasten 20kg of deck and is getting a bit ridiculous. If I was to use just angle I could probably save 10kg easy. This would make the overall weight gain from tramps about 10kg, which should not be a problem.

    Thanks,

    Reinier

  3. #63

    Default Re: seawind 24 hard decks

    Hi Zed,

    Yeah, I looked at that video, but I could not work out how heavy the weight was. It does seem to demonstrate the capacity of the honeycomb to spring back after an impact rather than just dent permanently.

    Regards,
    Reinier

  4. #64

    Default Re: seawind 24 hard decks

    Re 8mm --> I must have read the site wrong, it was just a brief look! But I had talked to them in the past and the lady said the only choice under the 15mm was an 8mm non structural. Maybe I misunderstood what she meant! Maybe she was also talking honeycomb size! I was asking how flexible the stuff is before glassing, I had another project in mind.

    I would ditch the tracks and use brackets, I did and it has worked fine. They are ~30mm angle @ 3mm thick. Each one is 50mm long and they are spaced around about 350mm centers and fastened with monel rivets.

    1. It is lighter by a long way.
    2. It allows drainage around the end of the hard deck, I had a real slime issue with the old deck sitting on the old tracks.
    3. You can rivet them from the inside (rivet head inside), much nicer finish.
    4. I doubt you could slide into the tracks with a hard deck due to the curved shape on the outside and the difficulty getting over the rear beam... not sure about that, I guess it might be doable with the rear beam removed.

    Yeah I could not figure the weight of the battering ram in the vid either! However I can say my decks have never received a focused bash anywhere near that! The biggest pressure they have faced is waves from below, they can pop your deck up if it is not secured properly. With polycore I would use nice big washers to hold it down = 25mm SS.

    You can't taper polycore, the honeycomb is bonded to a scrim which is what the glass bonds to. You can't glass directly to the core, this is one of the bug bears with the stuff as it makes edge treatment a little harder than foam. I think Tony ran some 3mm aluminum in the track on the main beam to support the front end. I dunno what but I would guess that a T profile could be used, T bit in the track???!

    As for the back end you just build a fence to stop stuff falling off the back and to stiffen the edge. The deck dosen't line up with the beam at all (stuff goes between the beam and the deck!) so it is either that or hanging brackets below the beam somehow... too messy for me, I went with the fence and it works well.

    2c
    Last edited by Zed; 13th September 2012 at 02:30 AM.

  5. #65

    Default Re: seawind 24 hard decks

    Oh yeah, what about the preglassed stuff they do? Is that worth a look?

  6. #66

    Default Re: seawind 24 hard decks

    Zed,

    Funny you should mention the pre-glassed. That is what I wanted to get from them in the first place. However I was advised, that whilst they could make it no problem, the shipping cost would be enourmous due to the non standard size. I'm down in Victoria and Polycore is up in Queensland. So they advised me just to get the cores and do the rest myself. I've never done something that big so am a little daunted.

    I think you are talking me into replacing the track with brackets, but I'm not sure about the rivets. You would have to drill them all out if the boat ever needs to be taken apart. It would also be a problem if I have to beef up the decks. May just stick with bolts & nuts.

    Would it be possible to reduce the thickness of the core and then fill the exposed honeycomb with epoxy and microballoons? Surely you could glass onto that? I guess I should ask Polycore.

    Cheers,
    Reinier

  7. #67

    Default Re: seawind 24 hard decks

    I am in Melbourne as well

    You don't have to remove the brackets from the hull to remove the decks, they are permanently fixed to the hull with the monel rivets. Yes I did have to fill all the old track holes and redrill new ones but that is not hard and you hardly notice them from the outside as they are mostly below deck level. The inside will be repainted or flowcoated at some stage so that is no problem. As it happens my decks are riveted to the brackets with aluminum rivets, they are cheap and easy to drill out and replace each time I take the decks off (every few years!). I could only do that because of the thin 9mm ply, if I where to use polycore decks I would have to use SS bolts to hold the deck down to the brackets.

  8. #68

    Default Re: seawind 24 hard decks

    Quote Originally Posted by reinier View Post
    Would it be possible to reduce the thickness of the core and then fill the exposed honeycomb with epoxy and microballoons? Surely you could glass onto that? I guess I should ask Polycore.
    Yes but the bond between the epoxy and the core would not be very good at all. That is what guys like Tony have done before glassing the edges but IMO that is not structural, just dressing and sealing the edges. You need some strength at the front. It would be better to butt to the beam and put a web under the front edge to stiffen it than to taper it IMO. Either that add a lip to the beam like Tony did.

    The only other alternate I can think of would be to fashion a Cedar core in a wedge shape as desired then butt it up to the polycore and glass it in when do the rest of the panel. I think that may work, they only butt join the polycore panels anyway so you will already have one butt join each side using the 2400mm panels.

    2c

  9. #69

    Default Re: seawind 24 hard decks

    Did you ever come to a resolution on this? I have just found this forum and was on the old one for some time. I put hard decks onto my seawind 3 years ago and they have take a beating and work well. I used 3/4" end grain balsa sheathed in carbon (twill tri-directional) that I vacuum bagged on my porch floor. They are easy to lift being very light, bolt down with 6 SS bolts and have had up to 7 people standing on them without any issues. I live in Massachusetts so take them off when I pull the boat for the winter.

  10. #70

    Default Re: seawind 24 hard decks

    Wow,

    balsa and carbon... I am afraid to ask about the price...
    I do not know about others, but my project was on hold. First, family/work, then haulout for my finkeeler, then (Sandy came, I am in NJ) picking up bits and pieces and stuff, all while no electricity in the house...
    The Seawind on the trailer behind my house is fine, some dry leaves blown in and dirt, but the other boat is gone, today the city authorities allowed us to the yard, I was able to find my keel and parts of cockpit. My wife wanted to take a pic of the hull with the name on it, but no luck, it was probably scattered around and broken into smaller pieces, white boat/blue bottom... I could not identify in the pile of broken fiberglass.
    The good news - for the next season I am concentrating on the cat.
    So far my plans for the deck are 1/4 "" ply, glassed probably both sides, maybe some reinforcements.
    Alan, could you post some pictures?
    Last edited by YoungGrumpy; 11th November 2012 at 12:33 AM. Reason: typo

  11. #71

    Default Re: seawind 24 hard decks

    Alan,

    How do you use your boat? Do you race? Do you have any modifications or is it original configuration? My plans depend on the availability of a better quality ply in my local boatyard. If I would have to pay for the shipping of the oversized sheets, I might as well get something better, like, NidaCore, as I am on a budget, but convenience is even more important.

  12. #72
    Join Date
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    Default Re: seawind 24 hard decks

    Quote Originally Posted by YoungGrumpy View Post
    Wow,

    balsa and carbon... I am afraid to ask about the price...
    I do not know about others, but my project was on hold. First, family/work, then haulout for my finkeeler, then (Sandy came, I am in NJ) picking up bits and pieces and stuff, all while no electricity in the house...
    The Seawind on the trailer behind my house is fine, some dry leaves blown in and dirt, but the other boat is gone, today the city authorities allowed us to the yard, I was able to find my keel and parts of cockpit. My wife wanted to take a pic of the hull with the name on it, but no luck, it was probably scattered around and broken into smaller pieces, white boat/blue bottom... I could not identify in the pile of broken fiberglass.
    The good news - for the next season I am concentrating on the cat.
    So far my plans for the deck are 1/4 "" ply, glassed probably both sides, maybe some reinforcements.
    Alan, could you post some pictures?
    That certainly brings home the reality of Sandy.

    I admire your attitude to it all. Hope you have got electricity now.

    Mike
    Nothing works on an old boat, except the skipper.

  13. #73

    Default Re: seawind 24 hard decks

    The strength comes not from the core but the structural rigidity based on the 3/8" thickness and the carbon / expoxy on both sides.
    I made a template of cardboard and ran a 3/4" * 1" batten along both sids of the center pod and a similar batten on the hull sudes of each side. I cut scupper type reliefs and this batten sits on top of the cabin / hull join whereas te inner side rests on the battens epoxied and screwed into the senter pod. Both from and back of the decks have a slight kick up so the deck is flat but under the cross beams slightly.
    I laid out the end grain balsa onto the templates and the glassed one side with the carbon. This was the side that did not have the scrim on it so I ended up with a rigid shape. I then did a fit to ensure it was righ and then sealed and carboned the edges, and them the top after sanding the edges to get a flat take up. I then addd the kick ups after a trial fit and glassed them in. I then flipped it over and ran two cross battens 1" * 3/4" spruce and carboned them to the underside. The final was to verify a trye seal and then paint with an anti slip deck paint.
    I have had 7 adults standing on them is a 3-4' chop doing 12-14 knots and there is no deflection and they are very robust. I can pick them up easily, suspect they go agount 25-30 lbs each. 6 Long SS bolts secure them. I have photos.
    Used about 1 1/2 gal west system epoxy, i can fairing filler and the carbon
    Used the 50" wide twill which costs about $30 per yard and the end grain balse in 2' * 4' sheets also cost about $30 each. the sheets of balsa ship easily, unlike the ply.

  14. #74

    Default Re: seawind 24 hard decks

    Alan,
    I re-read the description one more time.
    What you've got is tight fit both to the hulls and the centerconsole slightly below the beams?
    How is the wave slapping under way? Does the spray still finds its way from below?
    And would you post some pictures? Not only it helps with design decisions, looking at other people's boats is very motivational.

    Thanks

  15. #75

    Default Re: seawind 24 hard decks

    Have been trying to upload images without success. Get a fatal error. Also can't seem to paste into this text box. The images icon on this page asks for a URL and I don't have one for these. Must be doing something wrong. Soon as I work out what it is I shall post. Have tried to attach.
    The clearance with the water even in a good chop is good. No oil canning or thumping at all. But I would not drop them more than what they are.
    Alan
    Attached Images Attached Images

  16. #76

    Default Re: seawind 24 hard decks

    OK, so finally got some images for you. Note that there is a crack of about 1/8 clearance all round to let water drain out. There is no splashing up from under except an occasional through the motor well. The boat is still wet in a hard chop but its from water over the bows. I am going to do weather dodgers for next year and the sailmaker is working them out now and doing the patterns. That way I'll not get water into the cabins and will have some protection from spray. Am also thinking about putting 2 person bench seats that have waterproof lockers on either side just forward of the cabin end so that sitting is easier for people and I can store lifejackets inthem to relieve space in the cabin. Once you start these projects they seem to grow and creep ....

  17. #77

    Default Re: seawind 24 hard decks

    I see.

    On the spray/lockers issue, I believe I've posted it already somewhere, from What I've found on the net, some designers/builders of a cats similar size make the middle beam (one with the mast) bigger/higher. Not only it has storage space, but keeps the spray from the bows away from the cockpit area.
    http://hem.bredband.net/b262106/Boat/ondeck.html
    is an example, as well as R. Woods cats.
    That is something I will work on next year. (once I see yours, and learn from your mistakes.

  18. #78

    Default Re: seawind 24 hard decks

    here's what





    i have, its a mix of 15mm klegecel, 450g biax, upica mat, ply core in spots. Jeff.
    Attached Images Attached Images

  19. #79

    Default Re: seawind 24 hard decks

    I had to google the Upica mat,
    Looks good

  20. #80

    Default Re: seawind 24 hard decks

    Quote Originally Posted by YoungGrumpy View Post
    I had to google the Upica mat,
    Looks good
    It(upica, coremat etc) is good & easy to incorporate into a polyester laminate, but very resin hungry & I wouldn't use it for a whole hard deck. The beauty of it is very simply you can add some bulk/thickness to a localised laminate area, which is what I did for the more vertical components of that hard deck. That hard deck comprises of 3 peices, there's a central cockpit where the footwell area is like an extended outboard nacelle, the areas to each side of the cockpit drop down land on the hull/deck join of the seawind. I installed the seating/cockpit because I always found the flat hard deck I replaced uncomfortable( & was made of 20mm thick solid nylon sheet & REALLY heavy).Jeff.

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