Mast Head Float: Pros and Cons
Guides and Blogs
A masthead float is essentially an insurance policy against "turtling" (when a boat flips completely upside down). While they are common in sailing schools, experienced solo sailors often debate their use because they change the boat's behaviour in high winds.
Pros: Safety & Recovery
- Prevents Turtling: The primary benefit is keeping the mast buoyant. This prevents the boat from inverting 180°, which is much harder to recover from and carries a higher risk of the mast getting stuck in mud or sand in shallow water.
- Easier Righting: Because the boat stays on its side (90° to the water), you don't have to lift the weight of a waterlogged sail and mast out of the water. This is a game-changer for lighter crews or solo sailors who lack the leverage to right an inverted boat.
- Reduces Entrapment Risk: In the event of a capsize, keeping the boat on its side ensures there is no "roof" over the crew, significantly reducing the (rare but serious) risk of getting caught under the hull.
- Protects Equipment: It prevents the mast from filling with water (if it isn't perfectly sealed) and stops the mast from hitting the bottom in shallow areas, which can bend or snap the rig.
Cons: Windage & Performance
- "Sailing" Away on Its Side: This is the biggest safety drawback. If a boat stays on its side in high winds, the hull can act like a sail. The boat may "skate" across the water faster than you can swim. A turtled boat, by contrast, acts like an anchor and stays put.
- Increased Windage: Even when you aren't capsized, a float at the very top of the mast adds drag. While negligible for cruisers, it can affect your "point" (how close you can sail to the wind) and overall speed in competitive racing.
- Weight Aloft: Every ounce at the top of the mast is magnified by the length of the mast (the lever arm). Adding weight at the tip slightly decreases the boat’s initial stability, though modern inflatable floats are very light.
- Aesthetics and Rigging: Some sailors find them unsightly. They can also occasionally interfere with the main halyard or get caught in the shrouds during rigging or dousing the sail.
9 Litre or 40 Litre-Which one ?
You choose a Crewsaver 9L or 40L mast float based on your dinghy's size, weight, and your sailing goals: use the smaller 9L for lighter dinghies or if you don't expect serious capsizes, but opt for the larger 40L for heavier dinghies (like Lasers, 420s, or older boats) or for increased confidence in windy/choppy conditions to prevent full inversion, knowing the 40L adds more drag.
Comparison Summary
| Feature | With Float | Without Float |
|---|---|---|
| Recovery | Easy; boat stays on its side. | Difficult if boat turtles (180°). |
| Drift Risk | High; boat may blow away in the wind. | Low; inverted hull stays stationary. |
| Mast Safety | High; won't hit the bottom. | Low; risk of "pinning" mast in mud. |
| Performance | Slightly more drag/weight aloft. | Optimal aerodynamics. |
Recommendation
- Use one if: You are a beginner, sailing in shallow water, sailing solo in a boat that is hard to right, or teaching children.
- Skip it if: You are racing in a fleet (where it might be against class rules) or sailing in deep, open water where the risk of the boat blowing away from you is more dangerous than it turning upside down.
