Masts

The main factors in choosing the right mast are the length, diameter and carbon content, as well as the bending curve and hardness. Each mast has different characteristics, but most modern sails are compatible with most modern masts (of the right length).

Mast length

Masts come in lengths from 340 cm to over 5 meters. In terms of increments, manufacturers have agreed on increments of 30. The most common lengths are 340, 370, 400, 430, 460 and 490 cm. Often you can cover several sails with one length, but many windsurfers have several masts in their luggage, which also has the advantage that you don't have to rig every time you change the sail.
The appropriate length for a particular sail can be read on the sail bag or on the sail. Mostly the mast length is given directly ("Mast"), but sometimes only the total length of the luff is given ("Luff"), here you can read out the mast length by taking the next smallest length - e.g. Luff 420 means you take a 400 cm mast and set the mast extension to (approx.) 20 cm.

Carbon content of the windsurfing mast

The carbon content mainly determines the weight, but also the bending properties and stiffness of the rig. Carbon is a hard but incredibly light material. It bends well, but has a certain stiffness and resumes its original shape well after rigging. The light weight of carbon masts is a big advantage and makes the whole rig lighter and easier to handle. So you have more power for surfing and maneuvers.

Mast hardness

Apart from the length and the carbon content, you can often find a third indication on the mast, namely the mast hardness - IMCS (Indexed Mast Check System). In principle, the mast hardness can be varied according to conditions, but nowadays it is mostly standardized and depends on the length of the mast - e.g. 370 cm >> 17 IMCS / 400 cm >> 19 IMCS / 430 cm >> 21 IMCS. The hardness does not play a major role nowadays and is often not specified at all.

Mast diameter

Another important factor is the diameter. A distinction is made between SDM (Standard Diameter Mast) and RDM (Reduced Diameter Mast), also called "skinny". In the past, there were only SDM masts, but now almost only RDM masts are used in the smaller sail sizes, because they feel lighter and have better handling. Larger sails are often still sailed with SDM masts, as they are more stable in pressure distribution. Depending on the mast, you may also need to select a suitable mast extension (RDM or SDM) as well as make sure the boom front piece fits - or use an adapter.

Mast Bend Curve

Especially with older sails you had to pay attention to the suitable bending curve of the mast. A distinction is made between Constant Curve (CC), Flex Top (FT) or Hard Top (HT). If a sail is designed for HT, for example, the sail may not stand up properly with FT and the performance may suffer as a result. You can find tables on the appropriate flex for most older sails. However, most modern sails use CC and you don't have to worry too much about the perfect bend. If you want to be on the safe side, you should buy the original mast for the sail, which has the perfect fitting bend.