I'm puzzled about the tying it on and using a weak link. Canisters permanently lashed down should have a hydrostatic release to release them, but AFAIK that doesn't guarantee they will inflate. The painter on our new 8 man is 11m long so the boat would have to have sunk 35+ feet before the raft automatically inflated. If the boat goes down in 10m of water after catching fire, you'll be waiting a long time for it to deploy itself.

The standard procedure is printed on the tin. Tie the painter to a secure point on the boat, lob it over the side and tug on the painter till it goes pop, climb in then cut the painter with the crappy floating knife provided. It matters not whether it is a valise or canister, as long as you can hoof it overboard sharpish if you need to. Which makes me wonder about a couple of biggish Sunseekers (not that they';re only ones guilty, I'm sure) where the raft is on top of the hard top. Fine if she sinks gracefully, a la Titanic, but probably not so helpful if the bugger goes up in flames and you want to get at it quickly...