CHAPTER 4   RIGGING

Sail

The safe sail area for a 9-ft. Pram is 60 sq. ft. maximal.

The boat is rigged with a standing lugsail.  The dimensions are shown in the drawing below.

Only one side of the sail, the head requires a modification of the tarp.

The new seam is 3" wide".  It is done with double side sticking tape, or by gluing the seam with a clothes iron that is turned up to approximately three quarters of its maximum setting.  This is the neatest, and the most solid way if you can get the “knack” for it.

Place a piece of ¼" rope in the seam with a half knot at each end on the outside of the sail.  Seal the ends of the nylon rope with a hot soldering iron.

The seam is further reinforced with 10 grommets with a ⅜" dia. hole, and a grommets with ½" dia. hole at each corner.  Before these two grommets are inserted into the corners, reinforce these two corners with patches as shown in the drawing on page 28.

            After the head is cut, a right triangle of material is left over.  The short leg of this triangle is 4.3".  From this material, for both sides, cut the reinforcement patches and glue them onto the four corners.  The four smaller, triangular patches go onto the luff and the leech.  The fourteen square patches are for the reef points.  These patches measure only 2"x2".  Altogether, 39 grommets are used in the sail.

Parrels

The top yard and the boom are kept against the mast by parrels.  A loop on one side of each spar is a simple solution.  It does not interfere with the spar adjustments when tuning the sail for (slight) weather helm.  The ¼" lines for the parrels are 3' long.

Top Yard

The head of the sail is laced onto one of the two 10' - 1½" dia. wood poles.  Drill a ⅜" hole in each end of the yard for the lace line, and to keep the line taut.  The ⅜" holes for the loop of the parrel line in the top yard are placed 24" apart.  The first hole is 30" aft of the spar end fore.

Boom

The foot of the sail is laced to the boom through the two grommets with a ½" hole at the corners and seven grommets with a ⅜" hole in between.  The ⅜" holes for the parrel loop are 24" apart.  The first hole is 18" aft of the in/outhaul U-link.  See the drawing below.

 

1.                  Make up the boom by gluing the ½" side of the last ⅝"x½" slat upon the narrow (¾") side of the 8' - ¾"x 1.3" batten shown on page 11.  The ⅜" holes in this slat are lined up with the grommets in the foot of the sail.

2.                  Round the edges of the boom.

3.                  Attach a stainless steel block hanger at of the boom length aft.  The head of the single sheave block with head and becket is hung at this hanger.  The mainsheet is attached to the becket of the block.

4.                  Drill a ⅜" hole fore at the boom.  Attach a stainless steel U-link at the hole.  The in/outhaul line is knotted to this U-link

Mast

The length of the sail at 2.5' aft of the luff is 7'.

The length of the 10' - 1½" dia. mast above the mast thwart is 8' 9¾".  With an extra 2" deducted for the fairlead at the top of the mast to hoist the sail, it gives enough room to attach the halyard at this point to the top yard for the first sail trial to find the correct point where the halyard should be tied for a slight weather helm.

Halyard, Halyard Belaying Spoke

Make the halyard 20'.  Drill a ⅝" hole in the mast thwart about 2" beside the mast and 1" fore of the rear edge of the bench.  Round the edges of a 12" - 1x1 until it will fit into the hole in the bench.  Glue it in the hole with equal ends protruding above and below the thwart.  Belay the halyard onto the spoke.

In/Outhaul

With the in/outhaul the sail is fine-tuned for a (slight) weather helm.  The line is 18' long.

1.         Mount a fairlead with a ½" hole on the centerline of the bow deck 4" aft of the bow board.

2.         From the middle thwart plus an extra 12", lead the in/outhaul line to the U-link fore at the boom.  This is the inhaul part of the line.  Attach it with a knot to the U-link.

3.         From the U-link, pull the line through the fairlead and lead it back to the middle thwart with another extra 12" to spare.  This is the outhaul part of the line.

4.                  Make three or four knots in both ends of the line 2" apart. 

5.                  Make a 2" deep-V notch in the middle thwart.  Belay the end of the haul that is pulled taut into the deep-V notch.  The knots will hold the boom in position.

Painter

Attach another fairlead on the middle line of the deck 1" aft of the bow board.  Attach a 7' painter to this fairlead.

Mainsheet

The mainsheet is 20' long.

1.                  Bolt a stainless steel U-bolt onto the middle thwart behind the dagger board case.

2.                  With a stainless steel U-link attach the head of a double sheave block to the U-bolt.

3.                  Attach the single sheave block with its head to the block hanger on the boom.

4.                  Knot the mainsheet to the becket of this block on the boom.

5.                  Lead the mainsheet through the block on the thwart back to the boom block.

6.                  From the boom block, the mainsheet goes back to the second sheave of the thwart pulley.  The end of the line is ALWAYS held in the hand.

7.                  Push the boom out to a 90º angle with the mast.  At this position, make an 8-knot in the end of the mainsheet.  Add another two meter (or yards if you live in the USA) to the line.  Seal the end of the line with a hot soldering iron.

Sail Plan

Duckworks Contest 2001

Sail plan of a 9-ft. Pram

Drawn by B. Migchelsen

Designed by B. Migchelsen

October 2001

 

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