When I go out on the Solent to go racing, I often see a lot of boats not even doing a single practice run before the start,” says Ian Williams. “And if you don’t do a practice run, you’ve got pretty much zero chance of getting your time on distance right.”

To a match racing helmsman like Williams, time on distance is part of his religion, although he understands why some sailors might be loath to practise such a critical part of the race. “Practising a timed run does require a little bit of planning. Maybe you’re late off the dock, you’ve got other priorities competing for limited time on the water, maybe getting the rig set up, practising your tacks and gybes – so I get it.”

But there’s really very little excuse for not working on your time on distance judgement. “It’s a learned skill. To some people it might come naturally, but for me, I do it much more mathematically. I’ve done enough of it that I think I can judge the distance quite well now,” he says with typical understatement.

“There’s no doubt that whoever you are, the more you practise it, the better you’ll get.” Here are Ian’s best tips for nailing your time on distance.

Do a practice run

Do at least one practice run before any racing start. If you’re in a big one-design fleet the start can be crucial. In a handicap fleet, nailing the start to the second might be less critical – even so, you definitely want to do at least one practice run to get a feel for the current and the wind and how quickly you’re going to close the line.

The key thing is always to make sure you’re near the start line 15-20 minutes before the start. Sometimes the pin end mark gets laid quite late, so make sure you’ve done everything else in preparation and leave those final minutes as an opportunity to test the line once it’s been set up.

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Judge distance

In match racing we normally have our bowman calling how long it would take us to get to the start line, updating every three or four seconds the number of seconds that it’s going to take to get there. I’d expect an experienced bowman to be within about 10% accuracy. It’s not an exact science, but when you get tuned in after some practice, your bowman should be hitting that level of accuracy.

We’re always thinking whether we want to lead or follow back to the line, so there’s an extra layer that doesn’t apply to a fleet race. But the principles of judging time on distance are the same. In a fleet race, the critical time is when you’re coming across on port and tacking in towards the line onto starboard – you need to know how long it will take you to get to the line from that point.

The five-second rule

I use a very rough rule of thumb for a zero current and a non-biased line. In pretty much any displacement keelboat it normally takes about five seconds to travel a boat length upwind. So let’s say we’re 10 boat lengths away from the line, in which case I know that it’s 50 seconds of full speed sailing to get there.

This is something I’d always confirm by way of a practice run. I’ll line the boat up on starboard, going upwind at full speed, then time how long it takes to do 10 boat lengths. So if it takes a minute, then I know it’s six seconds a length. If it takes 40 seconds, it’s four seconds a length. That will obviously vary depending on the speed of the boat, the bias on the line, and any current.

Knowing what full speed at the line feels like gives you the understanding of whether the fleet is lining up a bit too close to the line, or if you can afford to punch forward a little bit.

Race start for the famous Rolex Sydney Hobart. Photo: Rolex/Carlo Borlenghi

Recalculate for bias

Things change as soon as line bias or current come into play. The more bias on the pin, the more time you need to factor into your final run towards the line. If normally it’s five seconds per boat length, on a very pin-biased line it’s quite possible you’re looking at eight or nine seconds per boat length.

If you’re somewhere very tidal with a couple of knots of current, again you may need to adjust your time on distance dramatically. I like to express current as boat lengths per minute, So if you’ve got two knots of current against you, that’s about a metre per second. So if you’re in a 10m boat, it’s about a boat length every 10 seconds; over a minute, it’s six lengths. So your unit then is six lengths per minute. And you’d know at a minute out from the start that you really want to be six lengths further up-tide of where you’d normally be.

Reaching starts

As with upwind starts, I like to get a top speed and know how many metres I am from the line. One really important thing to know with a reaching start is what I call the Line Wind Angle; is the wind blowing straight down the line or rather from in front or behind?

Critical is how close you can get to sailing along the line at an upwind angle, as you’re likely to approach the start sailing upwind. If you can sail along the line like that you can stay very close to the line and then bear away with only a few second to go.

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