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September 1, 1999 Issue

September 15, 1999 Issue

September 1, 1999 Issue


by Bob Hicks, Editor

Early on at the WoodenBoat Show '99 a casual remark from someone deeply embedded in the wooden boat culture, suggested that just about all the new wooden boats to be seen at the show seemed to be of traditional design, perhaps, but built with plywood and glue. This set me off on a mission, to see if I could find amongst the many boats on display some that were traditionally built. Surely there would be some in this show dedicated to wooden boats, sponsored by the bible of the genre, WoodenBoat magazine.

My search was for new boats built today by professional builders for sale to wooden boat enthusiasts. My report on the show in this issue, carries the thread of my search as I comment on certain boats I at first thought surely were traditionally built, only to learn that they were not.

Far and away the majority were small boats built in today's way, glued together plywood sheets or planks, or woodstrips. Mahogany or cedar planking on oak frames, lapstrake or carvel planked, bronze or copper fastened, hardly a one. What seemed to me to always have been an important aspect of the wooden boat ressurrection instigated by John Gardner and championed by WoodenBoat since the early '70s, the traditional building materials and techniques, seem to be fading from the small professional boatbuilding scene in the face of realities not apparent when hope sprang anew for the good old ways a quarter century ago.

I am not a dogmatic adherent to traditional ways and materials, my first encounters with small boats were heavily slanted towards the charms of building and using such boats, but over time I drifted away towards a broader gauge affection for small boats that offered satisfying experiences both in building and using. Not being a craftsman, I found it much easier to use plywood and glue. So do many others it appears, and the boats being offered by professional builders are included and seem to be well received by potential owners.

They should be for they are very nicely built and typically of traditional designs recognized for useful and enjoyable characteristics afloat. The glue and plywood don't seem to be a problem in acceptability when the craftsmanship and the quality of materials is high. Just because these small boats are not traditionally built does not make them cheap copies. They are, many of them, in and of themselves quite distinctive and attractive small craft.

It's been about 25 years now since 1 first fell under the spell of a Swampscott dory. This doesn't seem a long time to me but it is a long enough time for circumstances to have changed, and several developments have seriously impacted on the traditional small boat building scene in just this short quarter century.

Cost is one. Labor intensive traditional building, at the much higher wage scales required for the builder to support himself and his family today, and the much higher cost of ever harder to find good natural wood, have driven traditionally built small boat prices beyond affordable levels for all but the well to do.

Utility is another. As access to the water grows increasingly difficult, most small boats have to be kept on trailers, spending but a small part of their time in the water. The boats never get to swell up and stop leaking. So sealed up seams become necessary. Glued seams. Plywood, glued up wood veneers, lends itself quite nicely to glued up construction.

Time, or the lack thereof, impacts adversely on the traditional ways. The professional builders are faced with the necessarily high cost of their labor having to be absorbed in the asking price for their work. Amateur builders seeking to build their own boats in limited discretionary time cannot abide the lengthy process of mastering and applying traditional building methods.

The erosion of reliance on traditional ways of building traditional boats has been recognized on the pages of WoodenBoat itself, where the long ago fires of preserving the old ways have now been banked by the onslaught of today's restraints. Increasingly articles in the magazine reflect the acceptance of glues, plywood, veneers, composites of materials in which only the "fiber' is still wood.

So my search for a traditionally built boat at the WoodenBoat Show of 1999 was doomed to not quite complete failure. Yes, I did find a couple, but just about all the new wooden boats were new construction of old designs using modem techniques and materials. I don't mind myself, but the old order does seem to be changing once again, yielding place to new.

September 15, 1999

GPS Utility

By Bill Perkins My only disappointment with my handheld GPS unit is its performance as a knot meter. Like many others, I suspect, I dreamed of instant and accurate speed readouts with which I would test minute changes of boat and sail trim. I now realize this isn't going to happen. I'll be keeping my hand-held snorkel meter, which I look at with renewed respect. I have developed a system for extracting what speed accuracy I can from the GPS.

The stated intentionally induced error of the GPS signal is currently "less than 100 meters." On Garmin's website, it's stated that a typical position error due to all factors is currently ranging from 60' to 225'. For estimating boat speed-alone, I'm comfortable using the 225' figure for the present.

My GPS unit has a man overboard feature. Press that one button and the machine provides a constant readout of distance and bearing to the selected point. The aforementioned error occurs when the unit fixes the position at both ends of the run. Assuming maximum and opposing errors at both points, the distance measurements will have a constant error of 450' or .074 NM. This is a very conservative assumption, but that's OK.

Time = Distance / Speed. Similarly, the minimum time of run required to achieve a given level of accuracy in a speed measurement is equal to the assumed error of the distance measurement (.074 NM for my purposes) divided by the allowable error in speed measurement. I've rounded the run times up to convenient fractions of an hour for pencil and paper solution, but of course a small calculator allows quick solutions for any time of run.

The lowest level of accuracy I'm interested in is to the nearest 1/2 knot. Minimum run time (.074 NM/.5 knots) * 60 minutes/ hour = 8.88 minutes. The rule of thumb, make a timed run of 10 minutes (1/6 hour). Take the distance run from the GPS and multiply by 6 to get the boat's average speed over the ground. Round to the nearest 1/2 knot.

The next convenient level of accuracy is to the nearest 1/4 knot (.25, .50, .75). This takes twice the time to acquire as the previous example. Make a timed run of 20 minutes, multiply the displayed distance by 3, and round to the nearest 1/4 knot.

The highest practical level of accuracy is to the nearest 1/10 knot. Minimum run time (.074 NM/.10 knot) * 60 minutes/hour = 44.4 minutes. The rule of thumb, make a timed run of 45 minutes (3/4 hour). Take the distance run displayed by the GPS, multiply by 4/3 (11.33), and round to the nearest 1/10 knot.

If you start or end the measured run at a point of known latitude and longitude (or close abeam), you can enter these in the GPS unit as a waypoint and cut the acquisition time for a given level of accuracy in half. If a statistician would take on this problem, it would be interesting to learn the times of run required to achieve the various levels of accuracy 95% of the time.

All this requires no chart work on board and is hands free until the end of the timed run, very practical when rowing or sailing a small boat. Concerning chartwork, I think it would be convenient if our chartmakers started labeling the compass roses with the latitude/ longitude coordinates of the rose's center point . My GPS unit can plot a position relative to a stored waypoint, which I assume is typical. The position of nearby roses could be loaded in the GPS, and the boat's position plotted relative to them. A straight edge would register directly against the rose to supply the correct bearing. If the straight edge was calibrated in NM at the chart scale, a quick fix could be obtained with a minimum of plotting equipment. Even a piece of string would work.

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