Thursday, September 24, 2015

Chain Plate Job

Click any image to enlarge

wingssail images-fredrick roswold
Rust Stains Showing
For over a year we looked at these rust stains and even though no further rusting showed itself, we knew we had to get seriously into the chainplate issue.

Double Checking the mast for straightness
This is what we will try to get back to after the whole job is finished: A Straight Mast

Turnbuckles
This is what I have to take off to get at the chainplate. By the way, these are Kiwi-Rig Turnbuckles which we put on in 2000 when we replaced the rig in Tonga (another story).

Set Screws

Marking with tape
After loosening the lock nuts we mark the position of the turnbuckle with tape to make it easier to get the rig back in tune later.

Loosening
The rig is pretty tight and these turnbuckles, also known as rigging screws, are hard to turn. The small wrench holds one half of the screw while the main work occurs turning the bigger nut in the middle.

Two turns off
A good start is to let all the turnbuckles off a little bit. I used two turns to get started.

Down to one remaining shroud
Leaving one shroud on as long as we can meant that we still had support for the mast. By this time we also had set some halyards out to the rail to help support the mast. Once the shrouds were all off we worked fast to get the chainplate out, inspected, fixed and back in so that the amount of time when no shrouds were on the starboard side was minimal.

Ten bolts

Ugh! We had to drill out the fiberglass

Finally there is just a hole in the deck

Chainplate
Down on the dock we cleaned up the piece and performed a visual inspection.

Crack
Here it is, the source of all that rust. You can't tell how seriously the strength was effected but obviously it needs a repair.

Repaired
Our local welder ground out the crack and filled the resulting hole with new metal. Not perfectly beautiful, but it looks strong to me.

On the back

Edge

Bolting it back in
We put one bolt in on Monday night to enable us to attach a shroud.

Put on one shroud
This single intermediate shroud gave the rig a lot of support and gave us some peace of mind.

Temporary rain seal
Too late in the day to finish, we sealed the holes so rain wouldn't come in during the night.

Tuesday, All finished

Check for straight

After I finished the re-tuning it looked good to me, but this photo revealed that the mast is out about 1/2 inch at the first spreader. I'll make that adjustment in one of the next few days.

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2 Comments:

Blogger Ian McCallum said...

Interesting that you simply had the fracture welded. Did you check turnbuckle screws and rod ends? Best regards.

7:24 AM GMT+8  
Blogger wingssail said...

To answer Ian's Questions (Previous comment):

We last had this rig disassembled and checked in 2010, in South Africa.

This year we had good reason to suspect the chainplate. The other rig components could also be problems but so far they have given no signs. It is, of course, good practice to periodically check all of the rigging components, such as turnbuckle screws and rod heads, as Ian suggests, and additionally, all of the rods, spreaders, bend points, etc, however this requires removal of the rig, complete disassembly, and access to x-ray or dye testing services, neither of which are available here in Puerto Vallarta.

We all take chances with our rigs; even new ones break occasionally. Given the plans we have for Wings, which do not include ocean crossings or sailing in severe weather areas, and the length of time since the last check up, we think it is a reasonable risk to accept that we do not take the boat to the US to conduct this type of check up at this time.

11:32 AM GMT+8  

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