spar is a pole of wood, metal or lightweight materials such as carbon fibre used in the rigging of a sailing vessel to carry or support its sail. These include booms and masts, which serve both to deploy sail and resist compressive and bending forces, as well as the bowsprit and spinnaker poles.

Rigging Diagram

Rigging Diagram

This helpful reference list has been compiled to help you fully understand the intricacies of rigging, spars, masts and booms. If you are still unsure about anything, contact us.

Rigging Hardware Terminology

Rigging Hardware Terminology

Through our global network of suppliers, its very unlikely we wont be able to source a replacement for what you have. See our wire and terminology sections for further information.

Stainless Steel Wire Rope Spec

Stainless Steel Wire Rope Spec

Wire comes in a variety of layups, metals and specifications. When choosing wire it is important to take into account all of the factors which will be placed upon the wire in its intended use.

Spar Definitions

To help you understand the rigging process, we have compiled a glossary of terms, along with diagrams, lists and tables. If you still have questions about rigging, masts, spars or booms do not hesitate to contact us … and we will do our best to assist.

Mast Head

This is the top of the mast which houses the main halyard and the boom topping lift. In the case of a masthead rig, it also houses the genoa sheaves. The head is used to mount the turning block for a masthead spinnaker.

It is also used as a platform to mount:

Navigation lights

Electronic wind instruments
Wind vane
VHF aerial
Lightening conductor


The point at which the upper part of the rigging, that supports the mast, is attached. On a fractional rig, the hound is also where the genoa sheave boxes are situated.


The pair of wires that lead from the mast to the chain plates, to give lateral support. The term stays usually refers to the fore and aft wires (backstay, forestay and inner forestay).

Shroud Attachments

There is a number of different ways to attach the shrouds to the mast. The system will vary depending on the size of the yacht and whether it is to be used for racing or cruising. Refer to Rigging Hardware Terminology.



Lateral arms, usually aerofoil shaped, attached to the mast. The spreaders increase the angle of the wires from the hound, or head of the mast, to the chainplates. As the angle where a shroud attached to the mast decreases, the load in the wire required to stop the mast bending sideways increases. As a rule of thumb, 11 degrees is the minimum angle from the attachment point. In the case of catamarans, quite often spreaders are not required because the shroud base is so wide.

Where additional support is required to the mast column, diamond spreaders or jumper struts (as illustrated above) may be used. Diamond spreaders are in pairs (named because of the diamond shape the wire stays make). The diamond stays attach to the mast, lead out to the end of the spreader arms and attach back onto the mast. Large catamarans may have double or triple diamond spreaders.

Jumper struts are used where extra fore and aft support is required. They are mainly used to give extra support to fractional rigs. Jumpers can also be added to a set of diamond spreaders to give fore and aft support for a catamaran rig.


  1. The gooseneck is where the boom attaches to the mast. This is made up of three parts.
  2. The gooseneck lugs – these are either lugs on a plate that are fastened to the mast, or lugs welded straight onto the mast.
  3. The goosneck knuckle – this is the fitting that goes between the gooseneck lugs on the mast and the end plate lugs on the boom. The knuckle allows articulation of the boom joint in all possible directions while preventing the boom from rolling over which can jeopordise its structure!
    The end plate and lugs – this goes on the front of the boom and is built to have the gooseneck knuckle fit snuggly inside it.

There are a wide range of fittings both fabricated and cast on the market for goosenecks. Which to use depends largely on the application for which they are going to be used. If your unsure dont hesitate to ask one of our trained staff.

Vang Attachment

The vang attachment can be made up much like the goosneck if you require a solid vang (which supports the boom when the mainsail is lowered without you have to have the extra weight aloft of a boom topping lift). Otherwise the vang attachment can be a single lug which the block and tackle for the vang can be shackled straight onto.

Deck Collar/Partners

Some yachts (usually racing yachts) will have their mast go through the deck and sit on the keel of the hull below. Where the mast goes through the deck is often referred to as the “partners”. At this point you have to have a way of leading all of the halyards to the back of the boat where the crew can operate them. The deck collar fills this role by providing block attachment points as well as providing a solid point for deck tie downs. Every keel stepped mast should have at least one deck tie down, and it should be very secure. The deck tie down prevent the halyard load from pulling the deck up around the mast, thus possibly causing structural damage. If you discover your yacht doesnt have any sort of deck tie down system contact us before doing any more sailing.

Mast Base

The base of a mast is the point where the large majority of the loads of the mast come into one point (the rest of the load going to the chainplates). It is very important that this part of the mast be held together with either a cast base or fully fabricated and welded base. This type of finishing of the mast prevents any damage occuring to the tube as the load is applied to it. Without this you can have a situation where the mast will either buckle inwards or outwards over time.

Mast Accessories

Depending on the type of mast and uses for the boat your mast could have any number of accessories. Taskers is able to provide support and advice on mounting systems, attachments and servicing of these accessories. If your unsure about any of these extra accessories on your mast, dont hesitate to contact us.

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