Recently a web site visitor wrote to inquire whether we would
recommend that they outfit their soon-to-be-cruising multi hull with a
Reef-Rite boom furler. Following is the relevant part of the reply:
My slow answer is due to wanting to think over the boom-furling question a bit.
I've always considered the boom furler to be a bit of an experiment for Adagio.
It has pros and cons, and it isn't that easy to objectively sum them up.
Pro:
Con:
I credit this particular problem to operator error (Steve).
I was putting a full one-turn flattening reef in, full main of course, when
I tensioned the halyard the pawl which captures the mandrel didn't engage. This
pawl takes the luff load so you're not depending on the furling line to resist
the halyard loads. So I raised and lowered the top 2 meters of main a couple
of times trying to get the pawl to engage. I surmise that I must have allowed
some slack in the furling line during these cycles. Because when I inspected
the furling drum after finishing the reef I found the classic "drill down"
of the line into inner wraps - as sometimes occurs with jib furling drums. In
the jib furler case one has access to the line on the drum and should be able
to clear the jam - or worst case, cut the line and reeve a new one. In the case
of our boom furler, the drum span is about 25mm (1-in.) and 250mm (10-in.) diameter,
and is inside the boom shroud.
I wasn't about to continue sailing in Tasmania conditions with a main that couldn't
be reefed. On the Reef-Rite boom there is no way to clear a such a jam without
disassembly of the furling drum. That means you have to get the sail off the
boom. Adagio's main is just under 1000 sq Ft. Even though it is light construction
Mylar/Dacron laminate (Doyle CL110p), the two of us cannot lift the entire sail.
So lowering and capturing that sail in gusty 30ish conditions isn't a happy
job. Bear in mind that all boom furling mains use a luff-rope, so whatever sail
has been extracted from the track when lowering to the deck is only under brute-force
control.
After successfully lowering and lashing the main to the boom (impossible to
flake and bag it in such winds), we are now faced with finding winds light enough
to take the sail off the boom, tear down the drum, re-reeve the furling line,
etc. The prevailing conditions were such that we might have waited a month or
more among the Bass Strait islands to get winds that are 5kn or less. So we
crossed Bass Strait under reacher only, then waited in Eden until winds dropped
enough to sort out the main.
This event highlighted what had always been a concern for us - dependence on
the furling line to reduce sail in a controlled manner. Most of the popular
non-megayacht production boom furlers rely upon a furling line drum, axially
positioned either in front of the mast (Leisure Furl) or inside the boom housing,
either adjacent to the luff (Profurl, Reef-Rite), or aft of the clew (Schaefer).
Furlboom uses a remote furling drum and chain drive. I've not inspected one
of the Furlboom systems, so I'm not clear on how easy it is to clear a jam,
as the photos show a protective shroud around the drum - no doubt it is easy
to remove.
The Leisure Furl drum is forward of the mast and theoretically accessible to
clear a jam, or to reeve a new line in the event of failure (I presume that
the cowl around the drum can be removed to clear a jam or re lead a new furling
line). The Leisure Furl design, in my opinion, is less desirable than the Reef-Rite
due to the universal-joint gooseneck, absence of articulating luff track and
that the high batten loads bear directly on the luff rope. Again in my personal
opinion, that design makes it very difficult to reef downwind in any real wind.
We think the ability to reef downwind in whatever conditions is particularly
important on a multi hull - so the Leisure Furl isn't suitable for Adagio. But
the inaccessible furling drum of the Reef-Rite remains a problem for which we
are still seeking a solution. There are several possibilities - remote the furling
line drum under the boom so that the drum is easy to access, switch to electric
or hydraulic drive, etc. The options we have thought of all involve retaining
all the good design features of the Reef-Rite - only changing the way the mandrel
is driven, most probably via a chain drive connecting drum or motor to a sprocket
around the mandrel.
Another possible failure mode to consider is the articulating luff track. An
important feature of the Reef-Rite design is that the track takes the batten
loads rather than the bolt rope. This is a brilliant design so long as nothing
happens to the track that prevents lowering the sail. E.g., if misalignment
develops at one of the track joins? I think the Reef-Rite track system is very
well designed and robust, and we inspect regularly, but it remains a concern.
Other boom furlers (e.g., Profurl, Schaefer) also have articulating tracks -
I don't know any of their track details. In particular, whether the track design
absolutely eliminates any possibility of a luff rope jam.
Most slab-reefing mains have slides, so that the sail is captive at the mast.
In the event of trouble that makes a huge difference in manageability. FYI,
that is why we strongly favor Reef-Rite's jib furler design: the luff is captive
via the very clever Kiwi-Slides. This enables us to use the same furler for
the storm jib, and has the same benefits in the case of trouble. Insofar as
I know, their jib furler design is unique.
Adagio's original Reef-Rite boom furler utilized a similar idea to keep the
main captive. It was another brilliant idea, as it addressed issues of slides
entering/leaving the track and also excess bulk where the luff rolls on the
mandrel. However, Reef-Rite gave up on it due to too many problems with the
sail point loading at the luff attachments. So we replaced the articulating
track and had the main modified to use a conventional luff rope. Reef-Rite may
ultimately think of way to make it work.
Very fortunately, we had replaced the original luff feeder in
Hobart - specifically to ensure we could lower the main manually in case of
trouble. The original design worked very well but left essentially no clearance
between the feeder and boom. Therefore it was impossible to lower the sail in
an emergency outside the boom (without first removing the feeder, which is a
very tricky operation even in port). Reef-Rite has designed a new feeder that
we installed about 150mm (6-in.) above the top of the boom. This issue deserves
close inspection for any boom furler design - several that I've seen in photos
appear to have feeders that will not allow emergency lowering of the main.
So I think the bottom line is that slab-reefing has fewer serious failure modes.
Certainly things can go wrong - you will have 4 sets of reefing lines plus lazy-jacks
to deal with. But I cannot think of a glitch that can't be resolved at sea by
a couple.
Can we manage Adagio's large main with slab-reefing? Probably - but it is hard
to be certain until it has been tested with enough sea miles and challenging
conditions. Will we switch? Not until we've explored the alternatives for driving
the mandrel.