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Old 05-07-2017, 08:31   #16
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Re: Deck support beam have come lose

classic compression loading. you need a compression post under the mast step on deck and bonded to the keel floor timbers or the keel itself.
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Old 05-07-2017, 08:40   #17
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Re: Deck support beam have come lose

I also think this is just a cosmetic cover to make the boat look pretty. From the few pics posted, it does not seem to have any structural strength at all. This would also agree with simply being glued in position.

When the boat is in the water, the keel "hangs" from the boat, and the ends are pulled up by the fore and back stays, like a bow (think bow and arrow). But when on the hard, the keel pushes UP into the boat, and loosening the rig allows the ends to sag. It is pretty much a complete reversal of the forces the hull was designed for. So its not surprising to get some deformation. I've had it on my boats as well. This is why the engine should be aligned when in the water, not on the hard.

I suggest having another look at it, keeping in mind now that it may just be cosmetic, or a light stiffener to support the deck above, not the mast. What is directly above it? Main sheet traveller? Through deck bolts that need to be hidden? Is it a place you would normally step?
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Old 05-07-2017, 08:44   #18
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Re: Deck support beam have come lose

Quote:
Originally Posted by jimbunyard View Post
Would need a picture of the compression post to be sure, but to me that looks like some sort of cover, not a support beam.

If you left the rig untensioned over the winter and it experienced high winds, vibration could certainly have caused the cover to come loose, especially if combined with being only 'glued' on with silicone (as appears to be the case) and the hull distortion induced by being on land...

If you're unsure get some advice from someone who knows about these things in person, this isn't something you want to guess at.
It doesn't look like a structural member.
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Old 05-07-2017, 08:51   #19
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Re: Deck support beam have come lose

There is really nothing above the beam. It is placed between two windows and I store my life raft above it. This is under the bom so you wouldn't step in that area often
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Old 05-07-2017, 08:51   #20
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Re: Deck support beam have come lose

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Old 05-07-2017, 08:56   #21
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Re: Deck support beam have come lose

It looks like a piece of nonstructural trim to me. I would put it back with something less permanent than epoxy or 5200 in case it was attached with the intent of removing it later to maybe remove the headliner or something.
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Old 05-07-2017, 09:15   #22
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Re: Deck support beam have come lose

Davs, Flod :-)

I do not think that the damage you show in your photos is structual damage. It appears to be mainlya matter of the "liner", the dseparate moulding that in modern boats substitutes for interior joinerwork, having come losse from the basic hull/deck mouldings. That is serious enough, of course, and not something yyou should ingnore, and as other have said, it may be q
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Old 05-07-2017, 09:22   #23
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Re: Deck support beam have come lose

First, in my opinion it is false economy to leave a mast standing when the boat is on the hard. Cyclic loading on the stays will occur all winter, stressing the stays and causing premature failure.

It would be nice to see a photo of the "deck beam" removed and be able to see what is the structure underneath.

Maybe write to Dufour in French?
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Old 05-07-2017, 09:32   #24
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Re: Deck support beam have come lose

But why make it a c-channel if there was not structural support needed in that area. If purely decorative, and nothing behind it, they would have made it flat.

But, it also seems you would at least see a wad of structural bonding putty in that area if structural..... strange.

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Old 05-07-2017, 09:57   #25
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Re: Deck support beam have come lose

#22 continued:

quite expensive to repair.

However, the metal post that you show in #15 appears to me to be the compression post that takes the loads generated by the mast and transfers them to the sturdiest part of the ship, i.e the "keelson" - in modern boats, the top of the ballast casting.

The opposing forces are taken by the shrouds via the chain plates. These forces will tend to pull the rails inboard, i.e. they will tend to collapse the hull, and they must therefore be counteracted "isometrically" by a structural member that holds the rails, and therefore the chain plates, apart in the horizontal plane.

This in commonly achieved by dimensioning the transverse bulkhead(s) at the station where the chain plates are, so that it/they is/are capable of taking those forces.

All hulls flex, some more than others, and I would think that modern mass-produced "frozen snot" boats will flex more that those built in, say, the late 60s. That would be a natural function of the rise in the cost of resin and of the operations of the profit motive :-)

No boat likes being hauled, just exactly because of this propensity for flexing, and unless the strops (if your are hauling by Travelift) are positioned PRECISELY where the designer intended them to be positioned, flex will be induced as the weight of the boat gets localized where the strops are. Similarly, when the boat is supported in a cradle, the pads have to be positioned where the designer intended them to be positioned, or the hull will flex. In a frozen snot boat the hull may indeed come back to its intended shape when relaunched, but by that time an imperfectly "glued in" liner could well have come unstuck because it is a separate component not subject to the same flexing forces.

You also need to give some thought, when a boat is on the hard, to whether slacking off the shrouds and stays may FACILITATE flexing of the hull if it is not supported precisely where the designer intended. A rig is really and "integrated system" in which, if you muck with one part, all other parts are affected. Indeed, that is true for the boat in toto.

If I were in your boat - ahem :-) - I would spend the kroner required to get a COMPETENT surveyor to inspect the damage and tell you how to proceed. If you have "hull insurance" it is possible, but far from certain, that that would come into play. If you were hauled by a yard, as you indubitably were, and if, but ONLY IF, you can prove that the strops were negligently placed, and the boat damaged in consequence of that, you may even have an action at law.

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Old 05-07-2017, 10:25   #26
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Re: Deck support beam have come lose

Gives a whole new meaning to "bendy boat".
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Old 05-07-2017, 16:35   #27
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Re: Deck support beam have come lose

No way that is structural. If it was structural the beam would be fibreglassed solidly to the hull. It looks like it is just holding the deck head/liner up in place neatly. However the damage/unbonding may be signs of movement elsewhere such as the compression post/bulkhead moving. Best to get that checked out properly.

regards

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Old 05-07-2017, 23:41   #28
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Deck support beam have come lose

Thanks to you all for the good advises. To sum it up: I need to get somebody with knowledge of plastic and preferably this kind of boat to take a look at it and then hopefully repair it in a strong way so that it stay in place. I have inspected all other parts around the boat to look for other damages or deformations (keelsupport rod, deck to hull joints, walls to deck joints etc) so hopefully it's just this single damage.
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Old 06-07-2017, 01:07   #29
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Re: Deck support beam have come lose

First thing I would do in this case is inspect whatever the deck stepped mast support pole is mounted to. I often run into similar situations and find the culprit is that the mast support has been mounted on top of a plywood base, sometimes glassed in sometimes not. As this is both in the bilge and at the base of the mast, and therefore subject to possible exposure to both rain water and bilge water, it often rots. This results in the compression post no longer fulfilling it's designed role, as it has "sagged" by some distance. The fix is easy, pull the post and rebuild the base with G10 instead of ply. Not sure that's the root cause here, but it's the first thing I'd look for, especially lacking more info. It's the most common cause of saggy coachroof tops. Good luck!
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Old 06-07-2017, 05:23   #30
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Re: Deck support beam have come lose

This is out of my league but I have one, maybe naive, suggestion. I think, from reading your post you are back in the water, which is good.

Given all the knowledge from the others concerning flex, even negative flex while on the hard, you wouldn't want to fix the problem on the hard and have the repair "bonded" in the wrong position. It would then be under constant strain when splashed.
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