What grade of stainless?

[Bigtalljv]

Hi,

Any guesses on what grade if stainless the massive lifting eyes on my ex-military 7m zodiac would be made of? I need to make some changes and need to buy some similar stock. I can post pictures in the morning here if that would help.

Thanks
Jason

[beamishken]

316 a4 would be normal grade marine stainless but if they need to be certified for lifting then possibly something else.
I'd check the load rating on 316 if it meets the required load then I'd go with the 316 a4 stainless

[Bigtalljv]

Thanks, that was my guess based on what I’d read.

Jason

[GuyC]

Just to add to that - there are a number of strength classes. A4 relates to the chemical composition.

The strength classes are 50, 70 and 80 in ascending order of strength. 70 is 'normal'.

If the lifting eyes are fabricated from plate rather than being an eye bolt / nut, they are probably 316. The military tend to go large rather than go exotic - it makes field repairs easier.

[Bigtalljv]

Large indeed. 3/8” and 3/4” plate. 3” wide and 4” tall. Great for breaking toes on. I’m looking to go more of a recessed design.

[alpha]

This is a flush mount deck eye off my Zodiac. I don't think I would lift the boat with them but they are pretty beefy. I think those bolts are three-quarter inch.

[Bigtalljv]

One of the local harbor patrol boats is a 753, a 7m with a integrated fiberglass pod for the outboards. They have four very similar eyes they use to lift their boat. I’m going to use the rear two that came with the boat and still working on the front two. My boat only weighs about 5000lbs so it’s not a huge lift. I have a couple monitor marine quick release connectors that are rated for 2250lbs working load and 5:1 safety. Got the test results for them and they failed at 16,000lbs! They just look small.....