Replacing our chainplates was a long overdue job on our list. Conventional 316 Stainless Steel chainplates are prone to corrosion if any saltwater leaks past the sealant and sits on the backside or in encapsulated chainplates. We saw a ton of rust spots around a lot of our chainplates and bolts and knew that the chainplates were original from when the boat was built over 30 years ago so it was definitely time to replace them vs. just inspect them.
We chose to go with Grade 5 Titanium from Colligo Marine for 3 main reasons. Firstly, and most importantly the corrosion resistance properties of titanium. These chainplates will pretty much never corrode (except in the presence of a certain type of acid) and will far out-live the life of the entire boat. Second, the extra strength of titanium for the same size chainplate. We increased our yield strength by almost 4 and our tensile strength by almost double. Lastly, weight savings. We only saved about 17 lbs. in total switching to titanium chainplates and some of that is due to making two of our chainplates a bit shorter than the originals.
The two disadvantages of using Titanium for chainplates are the cost and how tough it is to machine. We were quoted about $1200 for x8 chainplates from Colligo some with bends some without. Depending on how long your boat lives the high up front cost of titanium chainplates may actually be cheaper in the long run. Titanium can be pretty tough stuff to drill and should be done with a proper bit and maximum pressure. I believe the holes in our chainplates were actually water-jetted. In addition, any bends put into a titanium chainplate MUST be annealed for fatigue resistance.
Here are a few pics of our newly installed titanium chainplates as well as a table with some rough weights, dimensions, and costs.
Titanium Chainplate specs – Some of these chainplates have bends which takes more time and labor to make and costs more
Titanium Chainplate
Many years of being a aircraft mechanic tells me that you should check to see if titanium and stainless steel are compatible. I know they are more so than other metals but they will still eat each other up, so you better keep a close eye on them. Should have used some disimialar metal compound on the bolts. Just a thought . Hate to see those titanium plates get eaten up