LENGTH OF SPARS FOR CUTTERS.
For cutters, the length of mast, deck to hounds, can roughly be put at 3 times the greatest breadth, and masthead of the length deck to hounds. Main boom, equal to the length on load line multiplied by 0.9.
Main gaff, 0.63 of main boom.
Angle of gaff with horizon, 50° to 55°.* Bowsprit outside the stem, equal to the breadth of the vessel multi plied by 2 ; or •45 of the length on the load water-line.
Length of bowsprit housed is usually the length of bowsprit outside multiplied by •4.
The topmast of cutters in length, from fid to hounds, is usually •8 of the length of the lower mast deck to hounds. In small cutters of 40 tons and under, the ratio is frequently •9, and occasionally a 10 toner may be met with the length of topmast equal to length of lower mast.
Topsail yards vary in length a great deal, but to some extent are guided by the length of the gaff over which they are set. Formerly all racing vessels carried a " balloon topsail," or a topsail with a long head yard, whilst the foot was extended beyond the gaff by a foot yard or jack yard. The head yard of a balloon-topsail was from 1.3 to 1.5 the length of the gaff over which it was set. The No. 1, or working-topsailt had a yard equal to the length of the gaff, and No. 2 topsail a yard equal to •6 of the length of the gaff. Cutters, however, do not now always carry a balloon
topsail, but have a big working topsail with a head yard of from to 1.2 the length of the gaff, and 2nd topsail •7 of the length of the gaff.
Spinnaker booms vary in length from 1.1 to 1.3 the length of lower mast deck to hounds.
These proportions for cutters appear to be followed with tolerable exactness, but are of course variable, as will be gathered from the table which follows. In this table, the length on the load line is given, and the breadth, and the proportions the spars bear to these dimensions.
Formerly the ratio of main boom to length on the load line was given at •97, but of late years the length of vessels in proportion to their breadth has been much increased; and the main booms now are more nearly 0.85 of such length.
The ratio of the length of the bowsprit is given in terms of the length of the load water-line, but it does not bear a constant proportion to that length ; in fact, the length of bowsprit is generally more nearly double the extreme beam; but obviously the length of the bowsprit and the length of boom or gaff must depend upon the requirements of the centre of effort of the sails, and upon their figures or shapes.