Rigging Small Sailboats

Chapter 3

.....spar components

The top of the mast is called the MASTHEAD, and depending on the type of rig, the fittings located here will perform various functions. Masthead fittings will also vary depending on whether a wood or aluminum mast is being used. The masthead fitting for wood masts is usually a custom unit made by the builder (see Fig. 3-9). When building a boat using wood spars, it is usually necessary to fabricate a masthead fitting. The designer should provide details for making the masthead fitting. For aluminum masts, the masthead fitting is usually a ready-made unit or "kit"-type assembly to match the mast extrusion, such as illustrated in Figs. 8-4 and 8-5. Obviously a masthead fitting for a masthead rig will be more complex than for a cat or jibhead rig. In any case, the masthead fitting contains at least one SHEAVE (a grooved wheel or pulley) for the main HALYARD, the line used to hoist the sail. With masthead rigs, the masthead fitting has a sheave for the jib halyard as well, and usually incorporates attachment fittings for the stays, and sometimes for the shrouds also. When a sock-type sail is used, and when the mast has no stays, then no masthead fittings are required. In any case, the top of hollow spars should be capped to keep water out. On wood spars this can be a sheet metal cap, and with aluminum spars, the masthead fitting will usually do the job.

On boats where the stays and shrouds do not go to the masthead, but fasten to the mast at some lower point as in jibhead rigs, other means are used to secure stays and shrouds to the mast. With wood spars, the conventional method used to attach the shroud and forestay is to use TANGS. Tangs are short metal straps usually with a crimp or bend to splay them out from the mast when in position. Another type does the same job, but these are of cast metal. The strap type usually has at least two holes; one for the stay attachment, and the other for fastening the tang to the mast. When aluminum masts are used, tangs bolted together through the mast can also be used for the shrouds, but the forestay usually uses another fitting called a HOUND (see Figs. 3-10 and 3-11). The hound wraps around the mast for bearing and has a fitting to receive the forestay. If used on a boat with a jib, then a JIB HALYARD BLOCK (fitting with a sheave used to lead the halyard and change its direction) is attached to the hound. If the shrouds and forestay land at the same point on the mast, then the tangs for the shrouds can be integral with the hound fitting.

FIG. 3-10 & 3-11 A hound strap fitting for use on jibhead rigs with aluminum spars. The hound provides attachment for the forestay as well as a block for the external jib halyard. The main halyard can be run either internally or externally. If run externally, it would run down the forward side of the mast along with the jib halyard (the most common arrangement on small boats).
FIG. 3-12 This photo shows several things. First note the relieved area along the mast for the sail bolt rope and gooseneck. The gooseneck has a shackle fitting with a pin through the cringle at the tack of the sail. The downhaul is used to tension the luff of the sail, and the line secures to a jam cleat on the mast. While the mast is aluminum, the boom is made from wood and is in an upsidedown "T" configuration for added strength. A fairlead at the mast base is used for the exit of the internal halyard which runs aft to a jam cleat on the deck. This small sailboat uses a stay adjuster on each shroud with tension adjusted by use of a turnbuckle on the forestay. The shrouds connect to chainplates, while the forestay fastens to a stemhead fitting.
FIG. 3-13 The sheave box is built into the mast at the exit point of the internal halyards to reduce chafe on the halyard.

When using internal halyards (those which run inside the mast), some type of fitting must be provided for the mast where the halyards exit the mast. Internal halyards can only be used in a hollow mast, and where used, they usually exit at or near the mast base. The simplest fitting is merely a hole through the mast fitted with a FAIRLEAD (a fitting to give a line a "fair lead") to prevent chafing the line (see Fig. 3-12). Another arrangement is to use COAMING PULLEYS or SHEAVE BOXES which not only act as a fairlead, but have sheaves incorporated to change direction of the halyards as well as preventing chafing of the line (see Fig. 3-13). These fittings are usually fitted into the mast near the base. In selecting coaming pulleys and sheave boxes, be sure the sheave of the fitting will protrude far enough into the mast so the halyards will not chafe along the inside mast surface.

Continued