there is a rule with the airlines, I think ,that as long as you notified them, its OK and think, take it on, as hand luggage, I some know skippers have done it with bag types, phone airline and have a chat is best way..
There are two parts of a raft that an airline might not like, one is the cylinder and the other is the distress flares, I had a customer who wanted to take one on the plane and he booked it on as freight for a few extra quid, you need to discuss thi wih the airline. One argument might be that the plane already carries the same equipment.
Many thanks all for the replies, the question arose as I would like to get a new liferaft for my new boat, currently in St Maarten, and the cost of liferafts locally is rather in excess of what I can get them for here. My thought was to put them in the hold as checked in baggage but the weight issue alone is causing concern never mind the fact they may be rejected at the airport.
Liferaft is fine, it is the gas bottle that is the problem. Empty it and there is no problem. (had to do this once in the check-in area at Gatwick - it is a very noisy procedure). The airline may want to verify that it really is empty.
If it contains flares it is a complete no-no. Few airlines would carry these even as dangerous goods, packed seperately in a steel fireproof box. leave them behind and get the raft serviced upon arrival.
It would be EXTREMELY dangerous to try to sneak either of these past the airline. Please don't try.