Page updated: 9 November 2011
This page contains the full text (as spelt and capitalised!) of the document supplied by Chris Jeckells from his company's files. As can be assumed from the memo, Mr Dennis Muirhead was the owner of Reedcraft.
Apart from, what almost anyone would consider, quite inaccurate observations about the performance of the SeaHawk, it is a classic example of both an employees frustration in what the author is asked to do and what he feels able to do (if only his employer would provide the tools), with equipment purchasing policies, and of the position of the sail maker's relationship with their customer. It's just wonderful stuff! You can't help but feel for J.S.S.!
There is a possibility, though unlikely given the dates involved, that J.S.S. had not seen what we now recognise as a SeaHawk, but rather one of the prototypes.
My rough sketch gives an idea of what they are driving at.
I would like a proper drawing with the effect this new rig is going to have on the balances and centres so that I can go cap in hand to see Dennis Muirhead.
26th Jan 72
Herewith scale drawing of a suggested larger rig for Sea Hawk. Dimensions of the proposed sails are noted on the luff, foot and leech. I submit the drawing with the following observations.
The standard mast is approximately 21' above the gumwales, which is already quite high for a boat of 14' 6" W.L. The proposed mast will be about 24' which would normally be considered excessively tall for a boat of this size.
I have not seen many of these Sea Hawks in action, but I have observed one sailing on Hickling Broad in light winds and the impression was one of excessive tenderness - almost hazardous crankiness. She increased the angle of heel alarmingly with the slightest puff which had no effect on the ½-decker I was sailing which was admittedly a stiff Broads Type, but with a C.B and no ballast keel. The boat is virtually a dinghy and presumably requires sitting out and handling like a dinghy, but the built-in accommodation gives the illusion of a keel yacht and people probably tend to handle it as such with uncomfortable results.
The sail balance of the new rig would be for all practical purposes the same as the standard rig. The C.E. however comes about 18" higher which with the increased sail area would have a markedly adverse effect on stability. I hope Mr. Muirhead will not ask you to be more specific and ask for definite information in concrete terms. Though I am quite competent to investigate stability and do the necessary calculations, we have neither the equipment, nor under Jeckells pressure, hte necessary TIME to undertake the work. (It would need in the first place accurate plans of the hull, with all sections and water lines. These would have to be re-drawn on a larger sacle and probably further stations interpolated. These sections would then have to be traced again with an integrator to obtain moments of inertia. An integrator of the simplest type used to cost about £75 pre-war, probably about £200 - £300 now. In view of the extreme difficulty I have to get a card index cabinet costing about 40p for sail plans, it is obviously out of the question - half the index cards are still in a cardbox taped up by the D.O. after three years!. a further requisite would be a large drawing board on a tilting stand with the necessary attachments for squares & protractors.
This raises the whole question of the proper functions of a sailmaker which as I see it, is to make sails to given dimensions provided by the customer or designer, who must take the responsibility for the result. I cannot really see that Centres of Effort, sail balance, degree of weather helm or such matters are anything to do with the production of sails, from the making point of view.
We should really function like a chemist making up a doctor's prescription, though we are often, particularly with so many Boat Show enquiries, in the position of chemist being asked to prescribe for and treat a patient whom he has never even seen and whose symptoms are described at third hand. If the patient fails to respond or dies in the process you cannot blame the chemist.
I do not thiik you need go cap-in-hand to Mr. Muirhead - any cap-handing should be done by the other party.
The sketch of the new rig was not supplied by Chris Jeckells. However, a rummage through the companies archives was permitted and the scan below shows what can be assumed to be a copy of the original sketch.
As suggested on the plan, the dotted lines appear to indicate the standard rig range of three headsail sizes, labelled jib, genoa and large genoa, and both main and large main sails. The sizes indicated for Jib and Standard Main do come to 126 sq ft, the size of the standard rig given in the Brochure.
As mentioned in the memo, the design for the taller rig calls for an increase in mast height of three feet. However, it did not mention that the revised sail plan was for a full mast-head rig, with two possible head and main sail sizes.