Anyone else suffered this experience or wish to comment?

Makes sense when it is brought to one's attention. Especially in this age of Chinese steel.

The nylon in the nut itself is sensitive to UV and sunlight (probably the salty environment too). It probably has nothing to do with 'Chinese' steel.

In fact there is not much on a boat that isn't susceptible to the marine environment hence why boats are so damn dear to maintain.

Seen similar in stainless products
Most probably stress fractures have occurred during the manufacturing. Corrosion then starts in the fractures and in no time the nut falls apart.
I would not say it's common problem with all nyloc nuts though.

A bit off the topic and good advertising for the product.

Select to expand quote

Jolene said..
A bit off the topic and good advertising for the product.

Interesting although they don't test star washers. Not that I have ever seen a stainless steel star washer but would probably be a better solution in non-marine applications.

Looks like they are subjecting them to extremely high frequency vibration as well which presumably isn't a problem on most yachts.

I guess it comes back to loctite. That was always the solution on motorcycles.

These are an alternative to nylocs but expensive

www.bolt.com.au/shop/fasteners-12-12-bsw-stainless-steel-304-glenloch-nut/#tab-title-technical_information