Internal Outhaul Arrangements

When acquired, Towser and Santiva had external outhauls that were unattractive and difficult to adjust. Replacing the old arrangement is not difficult, but necessarily two slightly different approaches were taken. Santiva's elliptical boom requires some re-shaping to accommodate sheaves while Towser's boom seems made for a system that was never installed. Santiva's owner elected to purchase a 4:1 tackle, while Towser's 4:1 cascade of blocks was dictated by her owner's possession of a collection of small single blocks.

Towser's boom end 1
Towser's internal cascade
Towser's inboard end
Towser's boom end 2
Santiva's boom end cutout
Santiva's inboard end

An Internal Outhaul for an Elliptical Boom

"After having examined a selection of diagrams, I opted for a 4:1 ratio. From there, I purchased Ronstan fiddle and fiddle-with-becket blocks and two Harken exit blocks (which they call "cutouts"), one of which must be suitable for the wire cable shackled to the clew. I was careful to choose a fiddle and fiddle/becket that fit inside the narrow confines of the elliptical section.

"The first step was to measure, with the sail foot in the track, how much space I had at the after end of the boom. Having removed the after-end fitting, I used a hacksaw to remove enough material from the top of the boom to accommodate the exit block, allowing for the end-fitting's intrusion into the boom. I cut the rectangular mounting hole for the exit block by drilling a pilot hole for a sabre saw blade and after filing the edges square, drilled and tapped the machine screw holes. The 5/32" cable I had made up is approximately 27" eye-to-eye with a thimble at each end. I chose that cable size because it fits within the sail slot, giving a clean purchase to the clew; 1/8" probably would have sufficed but I went for the largest practicable size.

"With the 4:1 tackle made up as in the Harken diagram of a 4:1 internal system, I measured 54 inches from the after end of the boom, where I drilled a 3/8" hole through the boom at its widest point. The bolt which goes through these captures the shackle on the forward part of the cascade (B in the Harken diagram). I opted to do it this way rather than taking the A-B line back to an internal eye strap (A) because installation of the latter would be virtually impossible.

"Then, rather than taking the line from C out through the side of the boom at another exit block and to a cam cleat, I fished it forward and out through the second through-deck on the underside of the boom. From there, the 5/16" line will be taken vertically down to a turning block at the base of the mast and then aft through a deck organizer to a cabintop clutch.

"A dry run in my home workshop indicates that it works smoothly but the real test obviously will be next spring when Santiva is returned to her natural element. My total outlay was about $110."

- Ken Pole