Chain-plate failure

[rdangaran]

My name is Richard Dangaran

Richmond Yacht club member

I bought my Olson25 in 1985 (sail-54).

I wanted to post the below information to help out Olson25 owners. I'm currently on the class email list.

Sometime in the mid to late 90s it was reported that water can enter the chain-plate and corrode the aluminum. I inspected the chain-plate then and I saw some water intrusion but once. I sealed the upper deck chain-plate and I would inspected the chain-plate from the deck and inside the cabin on a yearly bases. I didn't see any additional water intrusion.

For the 3rd time over the span of the life of the boat I was changing the standing rigging.

While I was tuning the rigging and adding tension - there was a big bang.

 

The starboard side chain-plate broke lose flush from the deck.The mast was still upright (miracle). I was lucky that I was doing this on the trailer. If this would have happen under sail I would have lost the mast. Two people from the club ran over and helped me secure several lines to the rigging to the toe rail. One of the persons helping was a rigger working on another boat in the yard.

The rigger removed both chain-plates the next day and it was only the starboard side that had any issue. The starboard side aluminum between the deck turned into aluminum and aluminum powder. Talking to Buzz he said once salt water penetrated the aluminum it was just a slow process of deterioration (something like eating itself to death). I order a new set of chain-plates from Buzz.

Recommendation to properly examine the aluminum chain-plate is to:

1.  Unbolt and pull out the chain-plate. Look for any aluminum deterioration (white aluminum powder etc.) 
2. Examine the wood between the upper deck and interior deck for rot or separation. The rigger put epoxy between the upper and lower deck from the deck plate hole.There was some rot but not in a load bearing area
3. My next goal is to examine the stanchion post.

I've included some picture to show the damage.

If you have any question you can email me at:

            rdan...@aol.com (Richard Dangaran)

Hope this helps out for all.