Have never owned in-mast furling
but while cruising we witnessed some people having issues with theirs. Make sure the boom is at the proper angle during furling. Having a hydraulic vang where 0 psi = proper angle is one way to go. Remove sail and have rigger fully inspect system prior to purchase
When we build sails
for in-mast furling, we take the following steps to insure maximum reliability
1. Follow all furler
manufacturer "instructions to sailmaker" to the letter.
2. Some manufacturers recommend no vertical battens so we follow that as well
3. Use Sailkote treatment at our production loft to reduce friction, make sail more wate repellent, and more stain resistant.
4. Design and build sail taking care not to allow for too much bulk at corner patches
5. Use Spectra webbing loop at head
. The webbing loops must be well done as they are prone to failure which necessitates a trip up rig.
Some boatbuilders make the mast a bit taller to compensate for the lost
Undeniable drawbacks are:
Hampered pointing ability due to leech hollow in place of roach
Increased weight aloft
may not last as long as they don't have the help of being supported with battens. We replaced a 3 or 4 year old furling main on a 54'. On the plus side, the sails are much less expensive since there are no batten pockets and no reef points. Construction time is more similar to a headsail.
If I were buying
a new boat or building custom, I'd do a conventional main and use a lazy bag (sail cover with integrated lazy jacks). If I were going custom route
, I'd give serious thought to a "Park Avenue" boom.