A Junk-rigged Scaffie

by Steve Ellis

When I bought Scaffie No. 64 four years ago it was my second boat, the replacement for a sixteen-foot sloop-rigged dayboat.  I wanted a smaller, simpler craft, one which would be quicker to rig and get onto the water.  I had seen a Scaffie called MOONSTONE ashore at Cobnor in Chichester Harbour and I thought the lines of the hull were very pleasing.

After experimenting with a larger lugsail I became interested in the idea of the Chinese or fully-battened lugsail (‘junk rig’).  I’m very pleased with the change and the following notes tell the story of “that junk-rigged Scaffie, MR. BLUE SKIES”.

Fig 1 - Sail Plan

The drawing Figure 1 shows the outline of the sail and indicates the size and position of the original lugsail (dotted lines).  The sail area is 117 sq ft, the same as a Dabber, (the Scaffie lugsail was 100 sq ft).  The mast is a metre longer than the original mast and it stands closer to the vertical (by cutting out some of the mast-step ahead of the mast, fitting a corresponding spacer aft of the mast, and a mast-gate).  The sail was second-hand, obtained from the Junk Rig Association (details at the end of the article).  The three rectangular panels are three feet deep and nine feet wide.

Rigging a junk involves a lot of pulley blocks and a lot of ‘string’!  Also, the mainsheet is not attached only to the clew of the sail but to several points along the leach, so I replaced the Scaffie’s ‘string-and-posts’ sheet-horse which would have been too far forward, by a steel horse about two feet aft of the stern.  The drawing Figure 2 shows the rigging. 

Fig 2 - Rigging

The components comprise:

  1. the boom, A-B.
  2. the sail battens, A1-B1, A2-B2, A3-B3, A4-B4, made from aluminium tubes.
  3. the yard, A5-B5.
  4. two ‘sheetlets’, which are loops of line fixed to the leach of the sail at the batten-ends, B and B1, B2 and B3.  The sheetlets support double pulley-blocks (back to back), DP1 and DP2.
  5. the mainsheet, which starts from a becket on a two-sheave block on the horse, runs around the double-pulley block at DP1, back to the horse, then around the second double-pulley at DP2, back to the horse, and then to the helmsman.  This results in a mainsheet which is 21 metres long!
  6. a halyard (omitted from the drawing) fitted with a small winch so that the sail can be raised single-handed from the helm station
  7. a throat halyard (also omitted from the drawing) to keep the yard close to the mast even when reefed down
  8. a sail-catcher (‘lazy-jacks’) rather like a topping-lift (two lines fixed at the masthead MH, run either side of the sail to the end of the boom at B, and have another loop which passes under the boom at LJ)
  9. a ‘mast lift’, which is a line from MH to port of the sail, secured to the mast below the boom at point ML.  The purpose of the mast lift is to support the front of the boom (just as the topping lift supports the aft end of the sail bundle) when the sail is lowered.
  10. finally, a ‘luff-hauling parrel’, (its use is described later), which is a line running from A5 then zig-zagging behind the mast and through a series of blocks at the front of the battens, (A2, A1, A), then to a block at the mast step, and then aft to be secured near the helmsman.

Now, that is pretty complicated for a boat which I had chosen as a simpler alternative to a gunter-rigged sloop …………… so how does it all perform?

Rigging before sailing is actually quite easy.  The mast is raised and secured in its step, then the sail raised and the throat-halyard tightened.  The sail slews forward because it isn’t suspended from the mid-point of the boom.  The luff-hauling parrel is left looped around the mast at the end of a day’s sailing, so it now needs to be hauled tight until the boom is horizontal and the sail takes up the position shown in Figure 2, with about 90% of the sail aft of the mast and 10% leading.  The mast-lift is then passed twice around the mast below the boom and secured with a few half-hitches.  The lazy-jacks have carabineer clips so no tying is needed.  After a quick look around to check for any snarl-ups the sail is lowered into the lazy-jacks and the boat launched. 

Once on the water the view all around is excellent because the foot of the sail is almost a metre above the gunwale, whereas a Scaffie’s lugsail is cut very low.

Sailing close-hauled is straightforward.  On port tack the wind presses the sail and battens against the mast, and on starboard tack the taut luff-hauling parrel stops the sail ballooning out to port and holds it a few inches away from the mast.

Reaching is an efficient point of sail (and of course there is a lot of sail area to pull).  I have a small GPS unit and have seen 5.2 knots registered on a reach in still water (i.e. no tidal influence), and that’s quite impressive for a waterline length of only 12’ 3” (3.75m).  I believe this is helped by the addition of a rather high-tech idea which was invented by a member of the Junk Rig Association two years ago. Junk battens used to be flexible, but this often meant that they didn’t bend at low wind speeds when a curve in the sail is beneficial, and bent too much at higher wind speeds when a flatter sail would be better.  MR. BLUE SKIES’ four battens are each cut in two places and fitted with nylon ‘knuckles’ which allow the tubular aluminium battens to articulate by a precise amount. 

Fig 3 - Batten knuckles

The illustration Figure 3 shows how this works: the nylon knuckles are a push-fit into the tubular battens, and are machined to a 6-degree angle (exaggerated in Figure 3) so that a 12-degree bend can be achieved.  The knuckles in each batten are at 20% and 50% aft from the luff of the sail.  The articulation in the battens produces a curve (of sorts) which generates more power than a flat sail.  The battens are held in compression within pockets in the sail so that the pieces don’t separate at the knuckles.

Running downwind is very efficient because the full-width battens makes the sail swing out rather like a barn door.  Before turning onto a run I slacken the luff-hauling parrel, which causes the sail to pivot forward so that instead of having about 10% of the sail ahead of the mast, it might be 25% of 30%.  Once turned onto a run this becomes 70 or 75% of the sail on one side of the mast, partly balanced by 25 or 30% on the other side.  By comparison all of a lugsail would be on one side or the other, and this part-balanced aspect of a junk rig seems to reduce the need for downwind steering corrections (which can become rhythmic over-corrections!).  Another (but tricky) advantage of the junk rig is that the boat can be sailed ‘by the lee’ with the boom more than 90 degrees to the centreline, if circumstances require it.

Gybing is quite easy to control because the battens and the multiple attachments of the sheet to the sail seem to slow down the sail as it comes across the boat.  But there is a lot of mainsheet to over-haul.

Reefing is the junk rig’s star turn.  Simply letting three feet of halyard run out drops the sail by one panel (23% of the sail area), straight into the sail-catcher.  Another three feet, another panel, 46%.  Another, 69%.  With the sail area swiftly reduced (and no knots to tie) the throat halyard then needs to be tightened, and the luff-hauling parrel too, but these involve just a pull on two ropes and re-secure to the cam-cleats.   Alternatively you can let the halyard go all the way and the entire sail drops safely into the lazy-jacks, in under ten seconds. This rapid de-powering of the sail has in the past led me to show off by sweeping in to a beach and ‘dropping it all’, but I’ve mostly stopped doing that since misjudging the depth and being catapulted from the thwart into the floorboards ………..

Finally, ‘un-reefing’ is also easy and quick, with nothing to untie.  Simply ease the throat halyard and the luff-hauling parrel, grind up the sail with the little winch, and re-secure the three lines into cam-cleats.  These are one-handed tasks while still at the helm, and the junk sail will allow you to do this ‘on the wind’ without coming head-to-wind.

In conclusion, this rig suits my needs admirably, particularly due to my having a propensity to leave my reefing too late ……..  I find the Scaffie’s hull-form delightful and my next projects are to follow John Sheldrake’s lead (Scaffie WIGEON), cutting off the two underwater fins and adding a centre-plate.


Useful data:

The Junk Rig Association, 373, Hunts Pond Road, Titchfield Common, Fareham, Hants, PO14 4PB                  Robin Blain   01329 842613

‘Practical Junk Rig’ by Hasler & McLeod, published by Adlard Coles,
ISBN 07136 4443 5, reprinted in USA by Tiller, ISBN 888671 01 7


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