How these mainsail modifications revolutionised by yacht’s performance

Safety and performance improved hugely when Mike Reynolds reduced the size of his mainsail and re-configured the systems controlling it

Our 1980s Yamazaki Yachts 34, Zen Again, is an IOR (International Offshore Rule) 3/4 tonner masthead cutter, with a fin keel and a skeg-hung rudder, displacing 6,000kg loaded for blue-water cruising. When we purchased her in 2010 she had a full-sized mainsail, conventional mainsheet and traveller, a simple rope kicker, two mainsail clew reefing lines, and ‘slugs in mast slot’ mainsail luff attachment.

She was designed for fully crewed racing and we quickly found that the main issue with the mainsail systems was safety. The full-sized mainsail may have been good for light airs whilst racing with four crew on the rail, but it was just too big for cruising.

The mainsheet and traveller were in the cockpit, creating a ‘death-zone’ during gybes. The rope kicker required a boom topping lift which proved to be a nuisance, and reefing without tack lines necessitated work at the mast. The mainsail luff attachment was difficult to reef due to the slugs jamming. In short, she was just too hazardous for two-handed cruising.

She is very easily driven, so slowing her down is often our primary concern at sea. With the original mainsail, we very rarely set the full sail. This meant that one of the reefing lines was always in use and putting in the third reef required re-reeving the first reef line.

So, when the time finally came for a new mainsail we had it made with the first-reef luff length and two deep reef points.

Upwind the new sail works well in light breezes. A notable example would be the time when we sailed 600 miles to windward in 10-15 knots from Panama to Jamaica – and would have left most displacement 40ft cruisers in our wake!

Broad-reaching with the new sail and our 130% yankee will give us boat speeds of five knots in 6-8 knots apparent – a 120-mile daily average and perfectly respectable for our little cruiser. It’s fair to say that our new smaller main has certainly been a huge improvement.

Control improvements

Over the years we’ve also added a Selden Rodkicker boom support system, several foot blocks, a boom brake, Tides Marine SailTrack and mainsail tack reefing lines, and have completely re-invented the mainsheet.

The Rodkicker eliminates the need for a topping lift, while more footblocks allow control of the headsail sheet, reaching sheet, staysail sheet and boom brake lines with one cockpit winch per side. The boom brake protects against involuntary gybes, and lets them happen safely if they do occur.

The SailTrack provides a low-friction slot for the new mainsail cars, simplifying and accelerating reefing operations. The tack reefing lines support reefing entirely from the cockpit, and the new mainsheet is now entirely outside the cockpit. The changes mean we now have a safer boat, having saved us from injury, and our boat from damage, on many occasions.

Foot blocks

Initially, we had one non-lockable dual foot block on each side to lead lines to the cockpit coaming winches. They were sized for 14mm-plus lines, as required in the 1980s. Because we had a single winch on each coaming, only one line could be used at a time.

We could run the second line across the cockpit to the windward winch, but that winch would usually belay (make fast) the checkstay (adjustable stay controlling mast bend). We wanted four 8-10mm lines each side (headsail sheet, reaching sheet, staysail sheet and boom brake).

The reaching sheet runs through a toerail-mounted block to lead the headsail outboard – very useful for trade winds sailing. We also replaced each old dual foot block with two dual lockable foot blocks. This was a huge improvement. It meant we could trim one line, lock it, and swap another line onto the winch. The modification was vital for installing a boom brake. Our headsail sheets are 8mm polyester-sheathed Dyneema and the boom brake line is 10mm double-braid polyester.

Boom brake

Initially we had a single tang (metal strip) under the boom for the kicker. It had two holes allowing both a solid kicker and boom brake to be fitted. We used a shackle and short webbing strop to connect a mountaineering ‘figure of eight’ descender to the boom, with the webbing preventing metal-to-metal contact between the kicker and the descender.

However, the solid kicker began to chaff the strop which required regular replacement. So, during a refit we had a second tang fitted aft of the original tang, with the solid kicker and boom brake sharing an extended backing plate. This solved the problem and greatly reinforced the boom.

The boom brake works brilliantly. A single boom brake control line leads forward from a foot block to a block shackled to the toerail, up to and through the descender and down to the other side and aft to a foot block. The 10mm double-braid polyester puts some ‘elastic’ in the system.

We always use the boom brake when sailing downwind, so it’s permanently rigged. To activate it, we simply take up any slack on the windward side and lock, then manually heave the leeward side tight and lock. No winching is required. If an accidental gybe occurs the boom moves across slowly.

When we are preparing to gybe we unlock the old windward side and during the gybe the boom brake will effectively slow the boom as it swings across.

Solid kicker

Changing to a solid kicker eliminated the need for a boom topping lift. The Selden Rodkicker’s internal gas strut pushes the boom up when we ease the kicker line. When reefing, this ‘scandalising’ of the mainsail removes leach tension, making clew line tensioning easy.

Mainsheet moved

Initially we had a conventional single mainsheet running from a cockpit-wide traveller. The traveller was on the bridge deck immediately aft of the companionway. These systems can be scary during intentional gybes and extremely dangerous during accidental gybes.

During a refit we had the traveller removed and added a stainless steel arch with mounts for two mainsheets – one on either side. From a 2:1 tackle each mainsheet is led forward to the gooseneck, down to the deck and back to the coachroof clutch and winch.

When sailing upwind the windward sheet acts as a traveller and the leeward sheet and the kicker itself act as dual kickers. When gybing, the mainsheet falls go through above the sprayhood well clear of the cockpit – so much safer.

The arch comprises dual 38mm-diameter, interconnected tubes with the forward tube securing the sprayhood and the aft tube providing a handhold. We placed the arch such that the sprayhood extended further aft, greatly improving the shelter it provides. The feet of the two tubes are splayed apart for strength, with a large baseplate between. The arch is bolted through the cockpit coamings with massive backing plates below.

Reefing tack lines

For safety reasons we wanted to be able to reef from the cockpit, which meant adding tack lines and modifying the mast gooseneck. The old gooseneck had conventional open hooks for mainsail luff reefing cringles. We needed closed rings through which we could lead tack lines. From there each tackline could run down to the deck and aft via deck organisers to coachroof clutch and winch.

During a refit we had a new stainless steel gooseneck fabricated. It is a thing of beauty and does the job very well.

Our mainsail has webbing strops through each luff reef cringle with D-rings at each end. The tack lines attach to the D-rings which can’t get through the gooseneck rings. Our mainsail has only two reef points since it is first-reef size (i.e. not full hoist). We can fully reef the mainsail with our two sets of tack and clew lines. The second reef is trysail-sized. The reefing lines are double-braid polyester – 8mm for tack and 10mm for clew.

Luff track

The most recent modification that we have made to Zen Again has been to successfully install a Tides Marine SailTrack. Previously our mainsail luff had cars and slugs which fed up the mast’s extruded slot. This worked quite well but it often required winching the luff down via the tack lines.

When we were reefing the full-length batten cars pushed forward and jammed even with wind out of the sail.

Low friction

We fitted the SailTrack when we replaced the mainsail, which meant we were able to have the sail constructed to suit. Fitting the SailTrack was simple with the mast out of the boat for a refit, but it can be done with the mast stepped. The SailTrack simply slides up the extruded mast slot and is permanently secured in place.

Instead of the mainsail cars/slugs working in the 38-year-old mast slot they now work in a low-friction plastic slot. The SailTrack has transformed our mainsail handling as the sail now hoists easily and literally falls down. The tack line’s purpose now is to hold the reef tack down – it’s barely needed to haul down the tack. We still release the kicker and luff the sail during these operations.

Soft attach blocks

For the mainsheets and other purposes we use Harken soft-attach blocks. These use 3mm Dyneema cord. We’ve used them across several oceans, replacing the cord every couple of years to avoid UV-induced failure. We still use stainless shackles on toerail-attached blocks due to the toerail’s rough inside edges.

So, after a decade of optimisation we now have a mainsail handling system that works flawlessly. Some of the modifications weren’t cheap but they have all made sailing safer and more fun.

Preventer or boom brake?

When sailing downwind you may want to set a boom preventer or boom brake to eliminate the risk of an accidental gybe. A preventer holds the boom forward using a long line from the end of the boom, forward to a turning block, then back to a clutch or jammer in the cockpit.

If you plan to intentionally gybe with a single preventer, you’re unlikely to want to go all the way forward to re-rig it, which means you’ll need two preventers, one for each side – a cumbersome solution that can lead to lines getting caught.

If your preventer fails to do its job, the ensuing accidental gybe can be dramatic and dangerous. I’ve known many boats that have had mainsheet, traveller or boom broken by gybes when the preventer failed. Even if nothing breaks, the boat will pirouette – because the main is pinned to one side by the preventer – putting a huge load on the rudder.

A boom brake, meanwhile, uses friction created by lines to slow down the swing of the boom. The amount of friction applied to the swing is controlled by the number of turns you take around a central hub on the boom.

Boom brakes do not necessarily require a large change of course when gybing. We simply release the old windward side of the boom brake, turn downwind, winch in the main, gybe, ease the mainsheet, and then lock the boom brake.

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