Hi, I have a problem with the shroud attachments on my boat and I'm looking for some suggestions/opinions.

I have a Sonata 6, but it doesn't have the original rig as far as I can tell. The original looks like a mast head rig with shrouds terminating at chainplates attached to the cabin. At some point in the past this has been changed to a slightly bigger fractional rig with upper and lower shrouds that terminate at saddles through bolted on the deck (one for each shroud). The deck is plywood cored fibreglass. There is a stainless backing plate of about 75x120 on either side of the deck.

The problem is that the bigger rig has additional loads and attaches at a point that was not originally intended, using hardware that I feel is not adequate. A while ago I noticed some cracks on the topside of the deck around the plate, probably caused by the extra load from the cap shrouds. To take some of the extra load I fitted an additional saddle on the underside of the deck on the same bolts as the topside saddle. I then attached a turnbuckle and ran this down to a steel bar running between two buttress pieces on the hull. This allowed me to tighten down the turnbuckle and spread some load to the hull.

I now want to upgrade this arrangement and replace the saddles with some proper chainplates. These will need to pass through the deck if they are to stay in line with the end of the spreaders. If I do this, what do I attach them to? They will be about 80mm from the hull and there is no bulkhead available. Would I be able to put a spacer, like a block of wood, between the chainplates and the hull?

I nearly bought one of these in the early seventies. Went to the factory up in Brookvale. I think I would look at up grading the SS strap arrangement down the inside of the cabin sides and maybe enlarging the pad on the inside of the hull as Andy59 suggests.

The advantage of the original design is that it provides sideways stability when raising the mast, plus makes it easier to walk along the side decks. I am a great believer in staying with the original design, unless there is a fundemental flaw in it.

Obviously the side deck was not designed to take the load. Why not go back to the original mounting, and maybe beef that up a bit?

I own a Sonata 6.
Looking at the internal pictures of your Sonata, it appears you have have a Sonata 6.3, which has a fractional rig.
Check out the Sonata website.

I'm not sure how much pressure that chain plate would be under. It would not be too hard to put another knee in and bolt a nice stainless chainplate to that. You could scrape/sand off all that flaking paint in the process and have a good look at those existing knees. Failing that a piece of 20mm marine ply epoxied to the 2 existing knees on the underside of the deck would be easy to do and provide a fair amount of strength to the attachment point.

wow, thats one bulbous keel at the bottom

That's a nice looking boat. With the chain plates off the cabin sides and on the deck set wider apart there is less strain. You might be a little over cautious!