I have had good results with this hook that is 10mm
stainless steel. They are AU $26.95. The heaviest
boat I have used this with was on a 46 foot flybridge
game fisher that was 23 tons & in winds up to 30 knots.
Key Benefits & Features:
For use in conjunction with a nylon springer to reduce the unpleasant shock loads associated with all-chain
anchoring. The hook is designed to fit between the links of chain while the clevis pin arrangement allows for easy attachment of the springer. Made from cast 316
stainless steel.
https://www.whitworths.com.au/products/43887_lg.jpg
Have also used this snap on
passage from St Marten & across the Pacific on a 60 foot cat. This one is AU $99.95.
Key Benefits & Features:
RF6300
Standard Snap Shackles
Fixed Bail
Heavy duty plunger springs and precision components ensure dependable
service. Body and hasp profiles are designed for easy clearance of lines and fittings when released. High strength to weight ratio. Split ring on plunger pin is spot welded for
security. A lanyard can be attached to the plunger pin for easy opening
Specifications
A 26.0 mm
B 19.0 mm
C 100.0 mm
D - mm
Max Working Load 2000 kg
Breaking Load 4000 kg
Weight 155 g
Materials
Grade 15-5PH investment cast stainless
steel body and hasp
Grade 316 stainless
steel plunger pin and spring
https://www.whitworths.com.au/products/79566_lg.jpg