Dear Editor,

John Clarke's letter (Bulletin 77) raises two very disturbing points. The possibilities of future legislation against Dinghy Cruising and the R.Y.A.'s monopoly in certification schemes.

Whilst wholeheartedly supporting the view that the D.C.A. should become active in this field, I feel that his suggestion for our own standards is too heavily biased towards established R.Y.A. standards. The R.Y.A. at present does little for Dinghy Cruisers and evening course certificates are naturally based upon big boat practice.

Navigation or Pilotage Dinghy Cruising-wise needs a very careful sifting out of the R.Y.A. Syllabus. Many useful guides for Dinghy navigation are absent and too many are quite impractical.

This does not mean that information gleaned from such a course has no value; an understanding of sophisticated navigational aids and methods is the basis upon which a Dinghy Cruiser must build his own navigational abilities.

Each will devise his own way to get over the practical problems - principally the exposed unstable working platform, which in good cruising weather can make even reading a book difficult, let alone conventional chartwork.

Dinghy navigation should differ from yachting navigation. Dinghy needs differ from yachting needs.

If the D.C.A.'s efforts to provide it's own certification scheme (which I am sure would boost membership) are to be acceptable to the authorities expected to impose legislation, we must surely quickly gather all the TIPS, AIDS, METHODS, etc. at present in use by D.C.A. members and combine the best of them into a solely DINGHY CRUISING SYLLABUS.

The article by G A Riley on the sextant is upon these lines but does certainly not go far enough. A coastwise cruise in a small OPEN BOAT is surely no place for a sextant!

I humbly offer my alternative.

Take a piece of string (terylene) and pass through the hole in 150 mm rule and tie a knot both sides of the hole as exactly as possible 600 mm apart. In order to find distance off an object of known height proceed as fellows.

Firmly grasp part of boat in one hand, with the other place one knot between teeth and extend rule to tighten string, holding rule at 9Oº thereto and vertically. With the thumbnail measure the apparent height of the object in mm. - rather as an artist measures perspective and scale with thumb and pencil. Replace rule in a safe place and grasp boat with both hands. Some mental arithmetic is now called for but should be well within the capabilities of anyone following more conventional methods.

Take known height of object in metres and multiply by 600 (times six and add two noughts). Now divide answer by number indicated by the thumb against the rule. This gives the distance off in metres; the clever ones will be able to rearrange the arithmetic to advantage.

Try it at home on your wife's knees (not upon)!

Known height of knees ½ metre x 600 = 300

Divided by apparent height of knees in mm. (say 150) = 2

Distance off = 2 metres

A six inch rule has other uses of course but probably cannot compete with the sextant at finding position by the three point methods, but I feel strongly that most dinghy cruisers can, with practice, better determine their position by a careful study of TRANSITS.

Transits are barely touched upon by most instruction books. I believe this is because they can be used successfully without instruments and it is difficult to exploit them financially.

Finally I suggest that the D.C.A. Bulletin would be the best medium for small Open Boat cruisers to sift out the best of the ideas offered and form them into a uniquely D.C.A. Syllabus.

J W Quantrell