A practical guide to selecting the right materials and specification of mast extension for you.
A REVIEW OF MAST EXTENSION TUBE TYPES
Aluminium Tube: More affordable than carbon, aluminium mostly bends rather than snapping, which can prevent other breakages in the event of failure.
Can be corrosion sensitive over time.
Carbon: Super light, no corrosion, slight chance of brittleness or susceptibility to impact damage.
MAST EXTENSION COMPONENT PARTS
Extensions of all grades still consist of component parts regardless what the main tube is constructed from.
Component materials have different strengths and benefits relative to their intended purpose or type of sailing.
Consider what your clips, collars, pulley blocks and bases should ideally be made of with this information in mind, as well as the availability of spares for repairs. (For example, aluminium coatings can see surface corrosion, whereas marine-grade Stainless Steel will have a longer lifespan, but a higher price tag.)
Polyethylene Plastic: is more flexible, which brings some disadvantages, but less likely to break apart as it’s less brittle.
This could suit more impact-heavy usage such as wavesailing or freestyle.
Nylon Plastic: stiffer and longer wearing, a bit more fragile/brittle than Polyethylene, although it’s not really a disadvantage.
This type of rigidity would suit higher performance levels of racing or freeriding for example.
Stainless Steel Reinforcement: Offers less wear and corrosion, but, along with extra peace of mind, also adds more weight - and cost.
MAST EXTENSION AND BASE PIN TYPE – U-PIN OR US System?
U-Pin vs. US Strengths/Weaknesses: The ‘U’ or ‘Universal’ pin is most common in Europe and the US-Pin most common in North America.
The U-pin also has less play and is mostly more ergonomical to operate.
US-Pin extensions tend to have less parts exposed to wear, which can be seen as an advantage on durability, but are fiddlier to operate.
The EU pin system (base plate + extender) is also lower in height. So a sail can be trimmed lower to your deck.
This means that for race or speed sails for example, it’s easier to close the gap (typically 2 cm. of difference between the height of and EU and a US).
Also this 2-cm. difference allows for a 2-cm. lower boom position that is a bonus for shorter riders.
OTHER IMPORTANT MAST EXTENSION CONSIDERATIONS
Using a shorter mast than quoted (say a 430 instead of a 460) with a suitable extension can bring interesting effects on sail behavior.
Using a lot of extension on high-tension rigs is not exclusively for carbon either.
For example, aluminium - with a wall thickness of 2.5 mm. or more - can still offer safe extension up to 45 cm.
Pulley Alignments / Orientation: Some sails have their pulleys ‘in line’ with the surface of the sail and some are offset by 90 degrees.
Similarly, some extensions have the pulleys set up to work best with one system or the other and some with both.
Matching alignment reduces friction when downhauling as well as allowing you to really downhaul as close as possible to the pulleys and reduce the elasticity of the rope. (It is possible to go below a ’0-cm.’ setting.)
Extra attention should be given when a Downhaul Winch is used.
The cleat must be closed on top. This to hold the line in place during downhauling.
The cleat’s ‘teeth’ must also be smooth and ‘rope friendly’ to prevent excessive wear during downhauling and under tension.
Different models offer a range of ‘rope-stashing’ options for tidying away the loose ends of the downhaul line.
TOP TIP: polish the cleat with an old Dyneema rope, forcing it by hand, under high tension, a number of times up and down.
Pulley Size for Purpose: A larger pulley diameter results in lighter, smoother operation, as does the number of pulleys.