Downwind sails are the most forgiving sails you will ever buy — but the rig measurements still have to be real. These are the coded values on our spinnaker / gennaker form (CS-SG-01), in centimetres.
Before you put a tape on anything
Use a non-stretch surveyor's tape with a retrieval line, on a fine, low-wind day. Hoist the tape exactly as the sail's head attaches and pull every coded span taut. And the sentence our form prints in bold, which is really the whole philosophy of this site: “Do not substitute specifications or an old sail.”
The coded measurements
| Code | What it is, and where the tape goes | Where |
|---|---|---|
| LpMaximum hoist | Maximum spinnaker-halyard hoist down to the deck / forestay intersection. | |
| JForetriangle base | Deck / forestay intersection to the forward mast face, horizontal. | |
| LpvHoist to bowsprit tack | Maximum hoist to the tack fitting on a bare bowsprit only. If your sprit isn't bare, this one stays blank. |
The numbers we accept but refuse to call geometry
The form takes your bowsprit length, pole length and furler dimensions — and files them explicitly as review values only. The reason is on the page: those measurements “have no universal source endpoints.” Ask three people where a bowsprit starts and you'll get three answers, so a bowsprit length without a declared unit and a labelled photo of both endpoints isn't a measurement, it's a rumour. We'll happily use it for review. We won't cut to it. The form also records whether you want symmetric, asymmetric, gennaker, Code Zero or Smart Code, whether there's a bowsprit, whether it's measured with a furler, and whether you use a snuffer — because a sail you can't douse is a sail you won't fly.
The rule that runs through every form we print
If you aren’t sure of a bearing, leave it blank and tell us. Our forms say it on every page, and it isn’t politeness — it’s arithmetic. A blank is a question we can answer with one phone call. A guess is indistinguishable from a measurement, so it survives all the way to the cutting floor and comes back as a sail that doesn’t fit. We would rather have four honest numbers and a note than five numbers where one is fiction.
The words on this page, explained
Or don’t measure anything at all
The easiest measurement is the sail you already own. Bag it, send it, and we’ll do all of this on a flat loft floor with proper tension — then send you the production dimensions to approve before we cut.