Please select your home edition
Edition
Upffront 2020 Foredeck Club LEADERBOARD

Bjarne Lorenzen interviewed: Furling Your Mainsail

by Andy Rice 7 Aug 2019 08:00 BST
Dacron Coastal Cruising Sail with vertical battens for in-mast furling © Doyle O'leu

Most of the time we think of furling headsails but as Bjarne Lorenzen of sailmaker Doyle O'leu explains, there are options for furling your mainsail too. In the fifth and final post from this series, Bjarne considers the pros and cons of 'in boom' or 'in mast'.

The choice of furling mainsails into the boom or into the mast partly comes down to local preference, says Bjarne Lorenzen. "In Germany we have more in-mast furling than in-boom. In Australia and New Zealand, however, we see more in-boom mainsails being used. It also partly depends on the make of the yachts. For example Bavaria, Hanse and Beneteau all offer in-mast furling mainsails as an option; most don't offer in-boom."

The in-boom option requires less compromise of your ideal sail shape, but it does require the angle of the boom to be precisely located before you start furling away the mainsail. Otherwise the furl will not go smoothly. Despite the challenges, as a sailmaker, Lorenzen tends to be more of a fan of in-boom compared with in-mast. "The sails for the in-mast option are very different. You can do a charter boat with negative roach which is quite ugly - but it's still sailing. You need vertical battens, it doesn't matter whether they are long or short battens, but they tend to be longer than normal horizontal battens. I can't say it's an elegant solution, but it works."

In-mast mainsails are very easy to stow away under most circumstances, which is what makes them so attractive for charter use. However, they're much harder to raise and lower in the first place, which tends to make this a once-a-season exercise. Lorenzen weighs up the pros and cons. "The shape is not as bad as people might believe. With vertical battens we can create a good roach, so the flying shape is not as disadvantaged as you might think. However, the mast is very stiff and you can't bend it much, so you don't have that last bit of control over sail shape like you might on other boats.

"The problems come, though, if you want to reef the sail or if it is damaged, because there is no way of lowering the sail easily with an in-mast system. The luff of the lowered sail is not attached to the mast, so the sail can easily get blown away during the take-down. The lowering of a reefed sail, which is already furled a few rounds, is impossible without the risk of damage."

The other factor to consider is that an in-mast option is a completely integrated rig package. You can't easily retrofit to an in-mast option for your boat without completely changing the mast too. There are some systems to attach furling systems to the backside of the mast, but these are relatively heavy and stop the mast from bending. The manufacturers are keen to keep the additional furling aluminium sections as small as possible which can make it tricky to get the full main sail rolled away in the available space.

In-boom furling avoids many of the compromises of in-mast, says Lorenzen. "Most of the in-boom mainsails are fully-battened, because you need the battens to keep the tension in the foot when you reef the sail into the boom. Also, you can achieve more roach in the sail with horizontal battens, so you don't really need to compromise your ideal flying shape so much." Raising and lowering the sail is straightforward compared with the much greater challenge of in-mast.

The in-boom option doesn't tend to come cheap, however. "In-boom customers are not your average customer; it's more for those aiming for a higher quality - for performance cruising boats, like Luffe yachts, a Swedish performance cruiser with carbon rig for example. In-boom is not going to appeal to the average cruiser with his Bavaria 34. This is for the keen cruising sailor who likes to spend more money on the boat, who appreciates really nice sails. In-boom enables you to trim the mainsail better and bend the mast if you are looking for that little bit of extra performance."

For more information on furling systems, or if you have any queries, feel free to get in touch using our contact form.

Related Articles

Morf Block merges into Morfrac Systems
Upffront.com speaks to the inventor, Nicolas Goldenberg At upffront.com we're big fans of the Morf Block. The lightweight, 3D-printed block started as a DIY kit and has expanded into two ranges: high performance and high load. Posted on 8 Jul
The Low-Down on High-Load Dinghy Blocks
Allen, Harken, Ronstan and Morf compared At upffront.com we love looking at the data and comparing products to gain insight. In this blog we look at the rapidly evolving world of high-load dinghy blocks and compare leading products on the market from Allen Brothers, Harken, Ronstan and Morf. Posted on 26 Jun
Spinlock's XTX available at upffront.com
The latest innovation in rope holding Widely known as experts in rope holding, Spinlock is the go-to solution for many sailors when it comes to clutches and jammers. We've been looking forward to the launch of their new product, the XTX Clutch, ever since we got our first look at METS 2019. Posted on 19 Jun
Ubi Maior X3M Flight Blocks
The compact high flyer reviewed by upffront.com Where does the Ubi Maior X3M Flight range sit relative to other blocks? Posted on 12 Jun
Allen Brothers overview from upffront.com
Dedicated to manufacturing excellence We are pleased to introduce the Allen Brothers 20mm and 30mm Dynamic Block ranges on the website and decided to take the opportunity to have an in-depth look at this fascinating UK manufacturer of performance dinghy hardware. Posted on 5 Jun
nke - Finding Their True Course
Upffront.com look at these high quality, precision navigation instruments nke is a specialist marine electronics manufacturer which has built a reputation, over 35 years, for high quality, precision navigation instruments for sailing yachts. Profiling companies like this is part of Upffront.com's raison d'être. Posted on 28 May
Ewincher - An alternative to electric winches?
A power-assisted winch handle requires no installation Electrification of winches can be a great benefit; reducing the strength and manpower needed on your boat and allowing many to sail short-handed or continue sailing longer in life. Is the Ewincher a viable, cost-effective alternative? Posted on 11 May
Extend your reach with Ronstan
The Battlestick is the self-professed 'next generation of sailing weaponry' Ronstan is an Australian born company who has developed hardware for both small and big boats since 1953. In this article we will look at their extensive range of tiller extensions which have become a brand in their own right: the Ronstan Battlestick. Posted on 30 Apr
Bamar's got your back... stay!
Looking to upgrade from a block and tackle system to a backstay tensioner? Looking to upgrade from a block and tackle system to a backstay tensioner? This blog will look at the Bamar BTV and BTM mechanical backstay tensioners and compare them with alternatives on the market. Posted on 23 Apr
PROtect Tapes SPK: Wooling spinnakers
An environmentally friendly and innovative system for solving an old problem PROtect Tapes provide solutions for the owners, boat captains and race teams who recognise that protecting the boat and reducing maintenance plays an important role in enhancing performance. Posted on 15 Apr