Hull and Cradle
BUILDING A J CLASS
See The Building of the Commemorative J100 [click]
below for a step by step account
Click on a Heading below or scroll down the page
What is a Canterbury J?
The Canterbury J is a project to let existing, or newcomers to the sport/hobby of radio sailing to get started quickly with a good handling model yacht that is easy to build and cost effective. Additionally it has ease of transport and a good resale potential.
The J is a 1.22 metre (48") yacht with a main and foresail rigged to a 1.6 metre aluminium mast.
Over 130 hulls have been sold in the last three years and they are to be found in all areas of New Zealand and some as far afield as the United States and Canada. It is a one-design yacht and all hulls come from a mold owned by the Canterbury J Association with an identification number moulded into the hull.
There are rules that
a) prohibit exotic materials,
b) define a fixed minimum weight,
c) dictate where ballast must be placed, particularly if the yacht is built too light and has to be brought up to the correct weight
d) strictly control dimensions in the three sizes of sail rigs.
It is not uncommon to see up to six yachts approaching the finishing line at the same time, particularly in light airs where the J's ability to glide on and on in a slight puff of air drives owners of other classes of yachts nuts. A great J attribute is its ability to negotiate weed and shallows and it is this characteristic that has been the saviour of our club membership during some difficult summers. With the J's popularity our membership has tripled in the last three years. It is a true pond yacht, but open sea trials have found that in a heavy chop it is hard to tack.
Another benefit is that within the basic parameters of the rules there is a great deal of freedom for the average builder to reflect ingenuity and skill, with the rigging, cabins and hatches, internal layout of components and deck layouts and composition.
The yacht can be bought as a kit or in separate pieces and assembled as the budget allows. This also allows members handy at making small components to make many of the parts and keep the price down.
A few club members coordinate the kits but the parts are made by many.
All parts are available: hulls white polyester, keels, brass fittings, and computer-generated sails, winches and radio gear. If you cannot find the part you want we will find it or we can make it at reasonable costs.
Because we are small non-profit organization interested in seeing the class grow and not a factory. We are at the moment restricted to one hull kit per week in the interest of sanity and to let us get some sailing done.
Orders are treated in order of reception.
Here in NZ, from start to sailing with a yacht personally made by the owner, the total is somewhere between $750 to $950.
A basic kit is usually around $600 according to what you order. Price lists are available.
We all work at different speeds and it is difficult to know how long anyone person will take on the project.
Most builders report that their models take about 100 hours to build over a period of six to eight weeks.
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30 hours would be spent working directly with the hull and keel
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30 hours on gluing timbers, sanding, finishing, and painting
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30 hours on the standing rigging (masts and booms, and sails), with the radio installation and with fittings and the running rigging.
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10 hours at least thinking about problems and conferring with others!
One builder built two well-finished Js in a fortnight!
However no matter how quickly or slowly we may pace ourselves, all builders of Js report that they enjoyed the building process immensely!
We can put J builders in contact with a mentor to see you through though the building and trimming phases.
Contact ~ Ian Scott or Bob Wing
Radios and Winches
Generally speaking, a simple two channel AM radio control unit suffices for controlling model yachts on the water. One channel is used for steering and the other for hauling in or letting out a single 'sheet' line which positions both the main sail and the foresail according to the direction of the 'apparant' wind. Some larger, usually scale yachts, do use more channels for operating additional sails, bells and whistles, maybe even an anchor or an auxiliary motor.
The disadvantage of basic (27 or 29MHz) two channel radio control units is that the number of operating frequencies is limited and on most ponds where a model yacht club is operating there is a rigid control of "who has what frequency". A new skipper is advised to hunt down a newer two channel rig that operates on the much higher bands (72MHz) where there are more frequencies (Channels) available. The cost of a basic two function set is around $160.00 to $250.00 and it includes, as well as the transmitter, a receiver, two standard servos and a battery case. One servo is used, one for spare, and the battery case is usually discarded.
The transmitter (the unit you hold in your hand) is often 'doctored' to provide an end to end rachet movement on the sheeting stick, and maybe even, some electronic tinkering within to control the number of turns the sail winch on the model will perform.
On the boat there will be a small receiver, its antenna, a battery, a switch, and two motorised extensions (servo and winch) from the receiver. Batteries are typically packs of five AA rechargeable nicads or metal hydrides though four dry cells are quite adequate for the occasional voyager. The servo used on the rudder is of standard type and has a short arm that moves through about sixty degrees in relation to the Transmitter rudder stick. However for the sail sheet, a much more powerful mechanism is required as the standard servo, except on the smallest models, is quite incapable of hauling in the sails against the wind.
It is possibly the choice of this sail winch that causes the new skipper most grief. Experience has shown that cheaper winches are either too slow, too weak, or too prone to faults, and the skipper quickly becomes disillusioned with this initial unwise purchase. Imagine a 500mm x 500mm piece of plywood held up in line to a 20 Kph NorWester and then demanding of a miniature motor and four AA batteries to move it through ninety degrees, square to the wind, in two seconds! And to do so again and again, week after week! So it is worthwhile considering the fact that the choice of a sail winch is even more important than the choice of the transmitter and receiver!
On the Canterbury Js, the Hitec HS-725BB and the SmartWich 280 sail winches are to be found in use most commonly. The Hitec costs around $130.00 and the SmartWinch around $280.00. This cost can be off-putting, but as is pointed out above, the sail winch is the most important part of the total rig! Looked after properly a good sail winch will last many years.
There is a great variety of 'running rigging' layouts to be seen amongst the Canterbury "Js" and how the winch is coupled to the sails is a subject of vigorous debate and constant modification - do take a look at the boats on the lake.
Some building pictures
See also
The Building of the Commemorative
Deck Beams---------------Deck and Fittings------- Painting progress
J 90 awaits her first sea trial