CHAINPLATE FASTENING

The chainplates are the attachments that allow to fix the mast shrouds to the boat. They are subjected to considerable forces, especially leewards. 

On the Amphitrite, we have to distinguish the chainplates located near the mainmast and the chainplates located near the mizzen mast.

The former are mounted on a laminated deck reinforcement, while the latter (we do not really know why) do not receive any reinforcements. However, these ones (chainplates of the mainmast backstay, mizzen shrouds chainplates) are very close to each other ; they exert a side lifting force out of the polyester sandwich and crack the gelcoat.

You can see the cracking of the gelcoat on these 3 pictures ; rust stains point out a leak.

A chainplate is a large stainless steel threaded rod that ends in an eye top and a nut down. It may be noted on the photo the part is curved or twisted ... (Point to clarify). It would probably have been preferable to mount stainless steel U-bolts, which would have better accepted a side angle of traction.

Generally, there is a stainless steel backplate inside, which is not always be fixed as it should and, often, we hear cracking and observe leaks due to the angulation of the shrouds.

In the middle, plates overlapp (bad because of watertightness) ; on the right, we can see gelatinous inefficient silicone.

The work of consolidation is relatively easy to achieve, not very expansive, but necessary to avoid that the deck suffers by the pull-ups of the shrouds : internal stratification to strengthen the deck and integrate the plates, sealing with Sikaflex 295 DC.

Below : the chain plate is curved, although the picture does not show it clearly.

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