It is reasonably easy on most boats with deck stepped masts to replace the mast with an in-mast
furler. You will need to replace your mast, mast step, and all of your
rigging. Depending on the design of your boat configuration of the new and old mast steps, you may need to modify the deck, its coring, and the below decks supporting structure as well. If the boat has a keel stepped mast then you will need to modify the mast partners for the larger sized mast as well as the mast step and cabin sole. Beyond that you will need to buy a new mainsail and may need to get your headsails recut for greater headstay sag.
All and all putting in an in-mast
furler on an existing boat is a very expensive proposition.
Beyond the cost, is the loss of performance, which is significant in light to moderate breezes, and beating or running at any windspeed, and reduced sail lifespan due to chafe and flogging. You may want to consider installing a taller
rig with more rated sail area in both the
jibs and mainsail to overcome the real loss of sail area and sail shaping efficiency that comes with a mainsail made for an in-mast
furling system.
Jeff
Then there is the third wammie. According to broker friends, this whole in-mast
furling fad seems to have peaked a bit. The say that more and more they are getting people coming in who will not buy a boat with in-mast
furling making boat with in-mast
furling harder to resell than they were. This has resulted in a drop in prices in these boats. In the past a boat with in-mst
furling demanded a much higher resale price. The brokers say that recently they seem to be actually selling for close to the same price or sometimes less than conventional
rigs, depending of course on the make and model.
So, for all of the expense you will end up with a boat that does not sail as well, and is harder to resell and which may sell for less than a boat without in-mast
furling. Sounds like a bad deal to me.