A small sailboat’s mast stands in a step on the keel or a thwart, passes through a reinforced hole called a partner higher up, and is held upright by standing rigging (shrouds to each side, a forestay to the bow) while running rigging (halyard, sheet, downhaul) moves the sail. A mast about as long as the boat, 8-10 cm across at the base and tapering above, weighs on the order of 9 kg for a 4.5 m softwood pole, so two people can raise it if the shrouds and forestay are already attached.
Part of Small Sailboat Construction
The mast and its rigging are the structure that turns a hull into a sailing boat: a pole in a socket, held by ropes, with other ropes to hoist and trim the sail.
Two Kinds Of Rope With Two Different Jobs
Standing rigging never moves while you sail. It carries the load of the wind on the sail down to the hull through tension in ropes or wires. Running rigging is the opposite: halyards hoist, sheets trim, downhauls pull the sail tight, and all of them must run freely through blocks.
The mast is held at three levels. The step takes its weight and the compression from the rigging. The partner, a snug hole in a thwart at about deck height, stops it moving sideways at the base. The shrouds and forestay hold the top. A rig with no standing rigging can work, but then the mast acts as a cantilever, and the base takes the whole bending moment; see Mast Construction.
What You Need
- A mast (see the next article) and a step, a block with a socket bolted to the keel or a thwart
- A partner: a thwart with a hole slightly larger than the mast, padded with leather or rope
- Shrouds and a forestay, with chain plates or lashing points at the hull
- Blocks for halyard and sheet, with sheaves that turn freely
- Two people to raise it, and a clear piece of beach
Method: Step The Mast Without Dropping It
Step 1: Fit the standing rigging to the masthead first, with the mast lying along the boat and the shrouds already tied or lashed at their lower ends to temporary points.
Step 2: Place the mast foot against the step, rest the top on the bow, and attach a line to the masthead for the second person.
Step 3: Lift from the foot, walking the mast upright while the second person holds the forestay line and keeps the top from swinging sideways.
Step 4: Drop the foot into the step and through the partner, then attach the shrouds to their chain plates and the forestay to the bow. Adjust until the mast stands vertical or a few degrees aft, no more.
Step 5: Check by eye and by plumb-line, from bow, stern and both sides. A mast that leans sideways when the boat is level means one shroud is shorter.
Worked Example: How Heavy Is The Pole?
A 4.5 m mast tapering from 9 cm at the base (the carrier gives 8-10 cm) to 6 cm at the top has an average diameter of 7.5 cm. Volume = π × 0.0375² × 4.5 = 0.0199 m³. At 450 kg/m³ (the midpoint of the 400-500 kg/m³ range for seasoned softwood in Logistics & Load Planning) the mast weighs 0.0199 × 450 = 8.9 kg. Green wood runs 800-1000 kg/m³ in the same table, so the same pole cut from fresh timber would be 16-20 kg: 0.0199 × 800 = 15.9 kg and 0.0199 × 1000 = 19.9 kg, a very different lift for two people with a pole that wants to swing.
Common Mistakes
- Stepping a green mast without checking its weight — the fresh pole is nearly double the dry one.
- A partner that grips the mast tightly — a rigid fit works the wood and splits the thwart; leave a small clearance.
- Raising the mast with the shrouds still on the ground — the top swings and no one can control it.
Safety
Raising a mast is a pinch and a fall hazard
Never raise a mast near overhead wires, live or presumed live, or on a windy day, when even a 9 kg pole can be pulled out of the hands of the person at the foot. Keep fingers clear of the step and the partner as the foot drops in. If the mast begins to fall, let it go and step back.
What’s Next
- Learn next: Mast Construction — choosing, joining and shaping the pole
- Combine with: Standing Rigging — the loads the shrouds carry