The Adjustable Backstay

Skiron has an adjustable backstay from the top of the mast to the stern. There are also two adjustable running backstays to employ when the storm jib is flown.

The vessels that I had sailed during my time of training with Club Nautique had fixed backstays from mast to stern. Thus, I didn’t truly understand the utility of the adjustable variety of backstay until I purchased Skiron and began to read on the topic and to experiment on the water.

The backstay on Skiron. It also serves as an antenna for the SSB radio.
Attachment of the backstay to the stern.
The part of the backstay that is adjustable with a standard winch handle.

I sailed in the SF Bay on June 28 with my friend and fellow sailor Paul McGraw. We had planned a sail out the Gate and into the ocean along the coast to Pillar Point Harbor at Half Moon Bay, an overnight stay, and then a sail back to Sausalito the following morning. Unfortunately, however, the weather forecasts were calling for sustained winds of 35-40 kn with gusts to 50 kn. The primary swell was predicted at 13-15 feet at 8-10 seconds. A second swell was predicted at a longer interval at 2 feet in height. The wind waves were predicted to be 9 feet. Combined, it seemed possible to see 25-30 ft or more seas in gale force winds. It was not something that we cared to venture into by choice. It’s one thing to be caught out in weather off shore but an entirely different thing to plan coastal cruising in the face of such predictions. So, we canceled our plans and decided to sail in the SF bay.

We, basically, had the Bay to ourselves save for one sailboat crossing a half mile away under engine power. Of course, there was some commercial traffic….the 1000 ft vessels hauling cargo to our shores from the Far East.

The conditions in the Bay were characterized by choppy waters. Wind waves were 3-4 feet. The swell from the ocean made its way into the bay but was only a few feet except near the Golden Gate Bridge where it was of a greater magnitude. The wind mostly exceeded 28 kn and the highest wind speed we noticed was in excess of 35 kn. These are not usual in the Bay….but I’ve seen worse.

The mast head. The adjustable backstay is the left-most wire attaching to the mast. The inner left-most line is the topping lift. The Genoa forestay is the right-most attachment to the top of the mast. The self-tacking jib is the next slightly lower attachment. This is a solent masthead rigged vessel.

We set sail with the main about 50% reefed. The old sails stretch in the wind so it proved that we had more camber than was desired and we headed into the wind and flattened the mainsail as much as we could to depower the sail. That wasn’t enough. We heeled a great degree and the weather helm could not be balanced by the full jib. The rudder was more than a half turn over to attempt to counter the heeling forces. So, we went back into the wind and reefed again. The situation had improved but the vessel needed something more. We now needed to depower the main and the Jib. The forestay sag was simply too much and now the jib was too full of wind. Yet, it wasn’t enough to counter the weather helm and lead to a comfortable amount of heel. What are the potential solutions?

Adjusting the backstay tension.

The most obvious solution was to crank tension into the adjustable backstay. Doing so will pull the top of the mast downwards and slightly backwards but, more importantly, bend the mast forwards in the middle. This has several effects on the mainsail. Basically, it depowers it by flattening it, increasing the distance between the leach and the luff, thereby reducing camber in the sail. The sail also twists off at the top and this further depowers the main. The forestay is pulled back and tightened. The sag is removed. The sail is flattened and the head also twists off leading to a depowering of the sail. We also tightened the outhaul to depower the lower part of the mainsail. As a result, both sails were depowered. The vessel was more controllable. Weather helm and heeling forces were reduced. We experienced these benefits and enjoyed our sail in 28-35 kn of wind. Skiron cuts through the waves well once satisfied with the sail adjustments. Our adjustments proved beneficial. We were making 6-7 kn upwind and 8-9 downwind.

Reefed mainsail.

Of course, the reverse is true, slackening the adjustable backstay is a marvelous technique to power up the sails in light winds.

Here’s hoping that you have the opportunity to gain experience with an adjustable backstay. You won’t regret learning this novel tool to fine tune your sails in different conditions.

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