I think for a boat of that size you will be requiring the proffessional services of a boat yard.
If you can get a crane alongside it would be feasible to do a DIY job if you have some experience in that type of thing and then somewhere to store them.The obvious place is usually on or under the boat if ashore.You need to construct some supports to lay the spars on .Headsail Roller reefing spars are vulnerable to damage if mishandled.
A crane with an operator who is used to this sort of thing.
You don't say where you are. Perhaps a bit of an overkill for a mast but for anyone along the south coast in the solent area who needs a boat lifted MEON VALLEY CRANE HIRE. A one man operation who is absolutely ace with boats. Sorry I don't know his max capacity but he does them up to 32ft at the yard I operate from.
in an emergency, you can do it yourself. Use the "Japanese method". Rigg a second stick (can be wood) just in front of the mast. The length of the stick has to be slighly more then 50% of your mast. You can construct a wooden shoe to protect your deck and keeping the stick from moving. Put up some temporary stays, to keep the stick up. Then use a 4:1 (mhmm how do you call this in english)
and lower the mast. Thats how it is done in Japan when a Taifun is coming. I have seen them doing it with boats bigger then 43 feet, but always the boat was resting on land. I would not try this method in the water myself. Otherwise, it looked quite safe.
My boat yard charge £50 to step the mast, quite cheap when you concider the damage that it would cause if "you" drop it?? Let the professionals do it.
Ahemm ! that dosent sound like me, but there are some jobs that are not worth the risk??????? /forums/images/graemlins/smirk.gif