How many times have you run forward on your racing or cruising boat to tend to something and along the way stubbed your toe on the Genoa sheet lead block? Some racing boats have up to three tracks, each with its own block, to increase your chances of bloodying more than one toe!
The hard reality, folks, is that these blocks are here to stay and whether racing or cruising, their position is very important in the setting of the Genoa. Before getting into the nitty gritty of sail trim, remember that whether you are racing or cruising, spend as little time as possible in the vicinity of these blocks. Failure rate is low, though under extreme circumstances and shock-loading, older blocks do explode.
If you are cruising, and you do not have tell tales on your sail, here are some ways in determining whether your lead is in the right position. If you draw an imaginary line through the clew of the sail and the sheet lead is in the correct position, you pretty much will be bisecting the angle of the clew. From the stern of the boat, look forward and watch the sail come into the rig after a tack. If the leech looks tight vs. the foot (red sail), the lead is too far forward and must come back. If the leech is open and the foot is tight (blue sail) once sheeted in, the lead is too far aft and must move forward. Notice on the sail in black how the leech and foot are set up correctly and the projection of the sheet lead cuts the clew angle in half.
On sails that have tell tales (those woolie things that flutter) the task of setting the sheet lead becomes a bit more scientific and a somewhat more exact. I must warn you, though, that if the sail is not shaped correctly or if the tell tales are not the correct distance from the luff, perceived information from these tell tales may be distorted.
First of all, a quick lesson on understanding how to read the tell tales. Normally, sail makers will put green tell tales on the starboard side of the sail and red ones on the port side. If you are on the foredeck facing the sail while sailing on the starboard tack and the headstay is to your right then you are looking at the starboard side of the sail. Opposite is true for the port side of the sail.
Let’s say you are on starboard tack and the green woolies are going round in circles or flying up. If the sail is trimmed in all the way and you think you are close hauled, the tell tails are telling you that you either have to trim the sail in or you are slightly above a close hauled course and you must bear away from the wind slightly. On the same tack, if the green woollies are flying aft and the red ones are dancing around, the sail is either slightly over trimmed or you are sailing low of a close hauled course.
Keeping what I just said in mind these are the steps you want to take in determining optimum sheet lead position. Set the sheet lead using my recommendations from the beginning of this piece and, in medium sailing conditions, point the boat on a close-hauled course. Imagine the sheet of the sail at the clew continuing into the sail with a pointer on it. Slowly bring the boat into the wind a degree at a time. If on the starboard tack the top green woolie jumps first, then the lead must go forward – in effect, moving the pointer to the top of the sail. If the bottom green woolie jumps first then the lead must move back – in effect moving the pointer down the sail to the woolie that you are going to correct.
Remember that if you have a reefing headsail, have more telltales in from the luff that you can also read as the first set will be in the luff roll. When reefing, the car will most certainly move forward.
Your third option, of course, is to invite your closest sail maker out for a sail and have him guide you through this same process!