In Mast Furling

balmar main furler

In mast furling consists of a roller furler unit fitted inside a mast section that has a slot in the aft end for the mainsail to roll in and out of. This mast section is larger than normally required and may require fewer spreaders due to the extra stiffness. The mainsail because it furls like a jib cannot support battens, hence the mainsail needs to be cut with leach hollow like a jib/genoa. Recently vertical battens have helped increase mainsail roach.

in mast furler
in mast furler

A list of production yachts at the Annapolis Boat Show using In mast furling include; Jeaneau, Hunter, caliber, Gozzard, Fingulf, Oyster, Hylas, Halberg Rassey, Bavaria, Island Packet, Catalina 6, Dufour, Beneteau, cruisers, Passport, Robi, Impression, & Wauquiez,

The Sparcraft in mast furler is one example of in mast furlers

In Mast furler pros & cons

In mast furling although a very convenient furling system it does has its pitfalls.


In Mast Furling Pros Cons
Cheap Weight up high
Simple to use Reduced sail area
No boom cover Poor light air performance
Furl to any sail size If the main furler jams you may not unable to drop main

In Mast Furling

Increasing sail Area

One complaint about mast furlers is the reduced sail area from the leech hollow. there are a couple of ways of increasing sail area.

The air batten From Halsey is an inflatable batten which is inflated when the sail is set, giving you much more sail area. More

Another idea from Halsey is the vertical batten.

In Mast Furling

Modifying an existing mast

Bamarbalmar main furler

There are some behind the mast options that you can retrofit your existing mast if you wish to convert to main sail reefing. Bamar external mast furling unit to add to existing mast section.