Fait le Minimum with Back Bearings
by Kate and Hamish Laird

	Ocean Miles: Anna and Helen circumnavigate the galley island a few hundred times en route to Belize.

French ocean racers have a saying, "Fait le minimum" - whatever the weather, just sail the minimum number of miles and you'll do all right. For cruisers, this makes even more sense - most cruising boats haven't a chance of chasing weather, so it's usually a good idea to sail the least amount of miles from A to B.

It takes a lot of extra speed to make up for the penalty of traveling 25 extra miles. Sometimes it's worth it - putting a few miles in the bank to windward, or following the squiggles of the Gulf Stream, but once we've decided on our route (even if it's indirect) we like to go there in as few miles as possible.

Hamish and I both started sailing during the brief reign of Sat Nav; the captains who taught us to sail were all sextant sailors. Now GPS is ubiquitous, but we'd been using it mostly as a lazy man's sextant - we'd hit a few buttons, copy lat and long down into the log and plot it on the chart. (oh my goodness we are Luddites; that's a paper chart! We just started using chart plotters regularly on Seal, and despite their power, we are still paper people.)

At the beginning of each passage, Hamish would plot out waypoints, program in a route, and we'd follow it, with a few adjustments along the way. When we were buying our GPS, I had spent days on hold to various GPS manufacturers to find one that would display VMG (Velocity Made Good or Waypoint Closing Velocity, depending on the manufacturer) on the screen. We finally achieved that with a Garmin 152 (the lowest end dash mount) and occasionally pick that up on the Raymarine Graphic 60 repeater in the cockpit (the NMEA/Raymarine communication still has some bugs to work out.) VMG is great for major decisions: was that tack the right thing to do? And it was helpful for decision making in steady winds - will my VMG go up if I fall off 10 degrees for some speed?

Seal's chart table and the forward end of the raised saloon.

But VMG and COG (Course over Ground) flutter too much second by second to evaluate how well one is steering toward the destination, especially in seas. Bearing to Waypoint is helpful if the waypoint is close by, but when it's 1000 miles off, you can have days of mediocre steering before the waypoint opens up.

Each hour or so, when I plotted the new position on the chart, I'd measure off the course made good with the plotter. The ocean charts were too large scale to make this worthwhile. "You could do it on a plotting sheet," Hamish suggested. "Or a small scale chart at the same latitude." We looked at each other. There has to be a way to do this on the GPS. We flipped through the manual but didn't turn up anything.

Hamish finally figured it out: Waypoints. Now, when plotting our position each hour or three, we put in a waypoint at our current position. If we then GO TO that waypoint, it shows us our back bearing, steady and unaffected by 10 degree deviations at the helm. Even an hour later, the waypoint isn't more than 10 miles away, so it's accurate in a way that our destination waypoint is not. Add or subtract 180 degrees and we have an instant Course Made Good accurate after a minute or so. We don't name these waypoints; the GPS automatically gives them numbers, and we delete them every couple of hours to keep the screen clean.

For the first couple of passages this winter, we used it long term, but we've started using it constantly. Current? Leeway? The back bearing gives us an instant check. Sometimes we do it every five minutes or each course adjustment, such as coming up into the Chesapeake two days ago with a lot of current and wind. Sometimes we do it every four or five hours, but it's made a big change in the number of miles we sail. On our first passage using it, from the Bahamas to Belize, we sailed 1092 miles on a route of 1077 miles. We haven't done that well since, but we have definitely shaved a good chunk of miles off by catching leeway and current quickly.

We tend to handsteer when under sail for the most part, and use the autopilot when under motor. We could avoid some of this tweaking by hooking up the autopilot directly to the GPS - I have the NMEA cables run and ready, but four months on, and I haven't connected them. Part of it was the heat of the tropics - I did no spare work in Belize - but part of it is a Luddite impulse to stay in the loop, to keep navigating. So instead, I work on sewing harnesses, and the cables stay curled in the locker.

And then the backbearing came into its own: the autopilot broke on our trip up from West Palm Beach, FL to Beaufort, NC and we handsteered under motor for 52 hours (we had a fantastic sail for 2 hours in a squall, poled out jib, gusts to 40 True, where the handsteering was fun, but otherwise, Mr. Cummins did the work, and we tried not to go crazy.) 538 miles on the helm: we did extra miles to stay in the Gulf Stream, but otherwise, we didn't want to motor any extra FEET, never mind miles. We did a backbearing at every watch change, and if someone happened up into the raised saloon to make a cup of tea, he or she invariably did a back bearing check on the helmsman. "Lean a bit more to starboard" was a frequent admonisment. It probably sounds overly fussy, but on the helm, we were glad to hear it - that might be a minute of hand steering saved!

	Anna in her cabin with passagemaking essentials: Legos and a bootlocker of Parmalat long life milk (behind her in the starboard cabin).

(The worst part about the autopilot was the fix was literally a five minute job...if only Hamish had brought his TIG welder with us. A welder in Beaufort, NC did it gratis in two, but we think we'll pack the machine next trip.)

Though our route in the Gulf Stream was anything but "fait le minimum," we did do the minimum on each leg of the route. We used the guidelines printed on the chart, positions provided on the NOAA weather radio on the VHF and watching the wrinkles of current alongside to stay in the heart of the Gulf Stream. We also noted the route of the northbound ships and followed their tracks, although they didn't make as much use of the Gulf Stream as we would have expected. In the future, we will look into Gulf Stream Routing: we might have saved the purchase price in fuel on this run, and it's even more important southbound. We picked up a steady two or three extra knots of boatspeed, and became quite used to seeing 11.5 knots on the SOG. In this case, it was definitely worth doing the extra miles for speed. Now we're stuck in the Chesapeake, with a week's worth of northerlies on the weatherfax and we're very glad we chose to interpret flat calm as a weather window.

You can learn more about the Lairds and SEAL at their website www.expeditionsail.com.