Last update, February 5, 2002
Just for fun...archived.
THE BIG DAY
It is exciting to take a new boat to the water. There is so much anticipation and hope. Hope? Yes, there is always this fear that it will not work. Be assured it will work. It may not meet all your expectations the first day, but it will work and it will sail and function well. If the boat meets all your expectations on this outing, you will be with the less than 10% range of people in the same effort. So, lighten up and have a good attitude, you might get lucky, and the best is that you are outdoors. There is a reason this is called a "Shakedown Cruise" by shipbuilders. As remote control modelers, you have it made; you could be throttling up an airplane you spent six months building.
If you have a choice, pick a day when the winds are light. It is easier on you and the boat. Take your lakeside gear and another box of building stuff from the shop as additional this first day. Make sure the batteries are topped. Do you have your boots? If you have a friend that is into this stuff, get him to come along.
If you know nothing else, rig the boat as you did in the pre-tune. Rigging will go faster as the settings should not have changed. The main concentration today is to sail with the sails full, no luffing, then deal with balance. If you can accomplish this you will have the rest of the summer to have fun and learn more. Slip the boat in the water with the sails out hauled and study the track quickly before the wind takes effect. If the rudder is off, it will not be by much. Make a slight adjustment in the trim and go for it. Bring the sails in and watch her power up but not to tight. It is recommended, having pre-tuned with the main close to the centerline, that you sail one or two bumps out on the control stick. Tight is for other reasons. Let her breathe a bit. Control the sailing. Make it go where you want it. Cruise and get a feel. Here is what you are looking for as mental notes:
Play with this till you have a good feel for consistency. Does the boat do the same thing each time? These are the four key things to concentrate on at first. Here is some information on these items:
If you can get control of these things you will do well. When you have time to think, or maybe at another session on the water, monitor the mainsail. There are some things that you can see well as a beginning captain. One is the luffing of the upper part of the main at the class designating numbers. This is the area of "twist." This luffing may mean it is twisted off too much. Tighten the vang a half turn and see what happens.
Second is a knuckle just behind the mast in the center of the sail. This will be a break in the smoothness of the camber. It is just like the JLA above but is called Main Luff Allowance (MLA). However, before you jump to conclusions and you are still on the water, trim out the jib a bit and see if it goes away. If it does go away then we say the jib was back winding the mainsail. This means the jib was in far enough to send a stream of air through the slot onto the surface of the mainsail. The slot between them needs to be open enough to allow a parallel flow across the main. The size of the slot and the twist of the jib to match the leech of the main will give you the flow desired. This will change with wind velocity but is the general idea.
If this was not the reason for the knuckle in the main then put a bit more bend into the mast. This will bow the mast forward in the area of the knuckle and flatten the main a bit. If the sailmaker's cut of the main luff (MLA) matches the bend of the mast, all will be well.
It should be noted that the jib and main luff allowances are very small measurements and made on a small sail. It cannot be expected that the intentions of the sailmaker will be perfect after you start screwing around with the rig. If you do not like taking notes, make a mental note where a sail wishes to live and work as opposed to what some chart says. Tuning by the numbers is a good way to start leaning but then it is like the front end alignment of your car, you have to make adjustments at times.
In another section and at a later time, other aspects of what you see on the water and what you do will be explored. Those mentioned here are the main issues and that, when on a beat to weather. You will spend at least 80% of your sailing this way and about as much tactical thinking during that time. You cannot win a race downwind till you conquer the beat.
Anyway, work with your boat and get it to run free with an easy touch on the helm. You will learn a lot in the process. Enjoy your boat; it was a good cruise; thanks for coming along. Enjoy the people and this is a nice way to spend a sunny afternoon by the lake.
Trim Angle, Balance, Righting Moment, Inertia
Think About It