Boat is 15 Tons (43 feet). Anchor is 33#. Rated for a 53' to 65' boat.

Seems light to me, aluminum I assume? My old boat was 11 tons and I
was using a 44 lb Spade. Only problem setting that I ever had was in
really soft, silt like mud. Lots of scope and a bit of settling time
fixed that one.

Presently I'm using a 120 lb Spade (30 ton boat fully loaded) which I
used to replace a 60 lb Bruce. The Bruce always set and held very well
but I was concerned about its reputation for slipping under heavy load.
The pre-purchase surveyor that I used said that he regarded the 60 lb
Bruce as a bare minimum. and not suitable as a storm anchor.