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# How To Make A Sail For An Aluminum Boat

By: Valentín PEREZ DUHALDE

Break Studios Contributing Writer

Do you want to know how to make a sail for an aluminum boat? Almost any fabric is good to make a sail. But depending on it´s weight, thickness and permeability will perform better or worse. Design, though, is the real key for a sail to work.

What you need to make a sail for an aluminum boat is:

• An aluminum boat.
• A mast.
• A boom.
• Rope and cable.
• Some ironwork on the hull.

The steps to make a sail for an aluminum boat are:

1. Determine the gravitational center of the hull. This can be done by different means. The most efficient is hanging the hull from a single point, and finding the point where the hull remains balanced.
2. Build a base for the mast. It must be placed on the gravitational center of the hull, and firm enough to withstand the weight of the mast, boom and sail, plus the forces that will be applied to it from any direction.
3. Place the ironwork to anchor the stays or cables that will keep the must upright.
4. Calculate the height of the mast. This will depend on the surface of sail to be used, but a basic ratio is roughly one to one between the height of the mast and the overall length of the boat. Remember that the boat´s ability to remain upright will depend on how much ballast it carries close to the bottom, and that also related to the amount of side pushing received on the sail.
5. Place the mast on the right spot. Reinforce the hull where the mast sits if needed.
6. Tie four stays from the top of the mast, one to each end of both axis. The ironwork at the hull must be strong enough to withstand some heavy pressure.
7. Place some ballast below the mast base. This way the boat will be able to withstand the side forces of the wind on the sail
8. Attach the boom to the mast. This must be done using a device that permits free turning of the boom while holding it in place. Different devices that are built on purpose can be used, but also this can be improvised using just rope. The point where the boom attachment must be placed should be as low as possible, while must be high enough to permit head clearance on the cockpit.
9. Measure the rigging dimensions. This will determine the size of the sail.
10. Cut the sail from fabric. The basic shape is one that has a square angle at the bottom, and then goes in a straight line from the top of the mast to the end of the boom.
11. Reinforce the angles of the sail. The points where each of the three corners meet the mast and the boom must have at least a double layer to reinforce the sail, as those are the points of most tension.
12. For better performance, the sail must have a belly shape. This is quite hard to do at home, but there are many software tools that can help you designing a very sophisticated sail.
13. Attach the sail to both mast and boom. The attachment can be fixed or removable. However, the simplest way to do it is sewing it making small holes and using a thin cord around both boom and mast. Make sure that the fabric does not rip after you make the holes.
14. Tie a rope at the end of the boom. This will be your boom line, that will let you manage the sail as you take turns.

The described is the simplest way to rig a boat. You can improve the design by using more than one sail, but with this design you will definitively move.

Posted on: Oct. 16, 2010