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By Craig Hohm - The Finger Lakes, New York - USA

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The Whaleboat Sailing Rig

Sails were often used in the traditional whale fishery, generally sloop rigged; most were sprits and lugs, with the occasional gaffer. Using the sail plan data from Willet Ansel's book, the total surface areas varied from 100 sq ft to over 350, with mainsails in the 200-300 sq ft range. The masts were 20+ feet. The lead (center of lateral resistance (CLR vs center of sail vector, eg center of effort (CE)) was near zero in all the plans I measured.

Historic sprit sloop

I worried that the size of the masts and the dimensions of the sloop mainsail would be too much for your average 21st century week-end whaler, and decided to divide it up into a ketch. The initial inspiration for this was Pete Culler's article on cat ketches, with information added from Phil Bolger's "101 sailing plans", and especially Tom Jackson's wonderful article about designing a rig for his boat in Woodenboat 202. The advantage of the ketch is that each sail is smaller, and the masts and spars are shorter; setting the rig up in the water is easier, and sheet tension is less overall. My spar length was set at 16' max , based on my available wood hoard. The sail division also allows for spreading the effort along the length of the hull and, thus decreasing the heeling force. Plus the mizzen could allow for boosting this long straight hull thru a tack, riding to while reefing the main, sitting at anchor, etc.

When I started this process a year ago I was drawn to a sprit rig. I have a Catspaw that I have sailed for twenty years and I love the sprit. I drew up an initial plan and pinned it to the wall while the hull was building.

Ketch alternative

Now and again I would return to consider it and became increasingly concerned about the trouble the main (at 120 sq ft) would cause during reefing. Sprits are simple, powerful and big for their spar length, but they are not easy to reef. The Catspaw was enough trouble at 60 sq ft; what would twice that area be like?

So enter the season of doubt. With the scale drawing on masonite and a big roll of brown paper I made enough sail models to paper a modest living room. With these models I was able to see the sheet leads and spar length and to assess the CE; Shallow man that I am, I was also looking for a certain rakish air, something to strike fear into my intended prey: "petrolphagia annoyus", the jet ski. I considered a gaff. but for the whaleboat the 16 ft mast would not allow for the enough surface area, and making the sail the same size would require a 20+ mast and shrouds. How about gunter?: Phil doesn't like them, which is enough for me. The mast height issue is resolved but he feels they are inefficient and prone to jam. The main contender is the lugger in various forms. The lugs are efficient, relatively simple, easier to reef and control. I like the way the dipping lug looks but did not want the trouble of dipping on each tack. The standing lug just looked funny to me with its forward canting luff. Phil likes the balanced lug, which he describes as self trimming, since the boom doesn't cock up downwind and the peak doesn't twist off. They are safe on a jibe and have better drive than the standing lug. They bundle up nice (like a sprit) for on-board storage. On the other hand they are not trouble free: the yard comes down first when the halyard is eased and this is a big spar (eg think hard hat here). The boom may trip the boat if it heels too far in a squall, and it does not allow for sail overlap. I drew up a number of sail plans for the balanced lug.

Balanced lug 1 : Bolger proportions
Balanced lug 2: Oughtred design

The balanced rigs make sense, especially vis reefing and downwind shape but the mast is taller for the same surface area, and the mizzen has to be moved back to thwart 5 (and honestly I just didn't care for the way it looked).

So back to the sprit; I like the overlap of the main and mizzen and wanted to keep it. This allows the mizzen to seat on the 4th thwart and the main to be boomless. This boomless sail goes out of shape downwind but has good power and more importantly allows for brailing (more later on this).

Ketch 2: reefed main shown overlaid

Between photo 2 and 5 there are small differences: the mizzen I made slightly smaller to move the CE forward, the peaks are slightly lower to bring the snotter within easier reach.

Calculating Sheet Leads

Would this long narrow hull allow effective sheeting of a loose footed main? Using the top down half hull view on the scale masonite drawing, I bent a batten to find the position of the the clew for the main and jib 10 degrees off the center line.

Main and jib curves

Then using the side view, these points, marked with red thumb tacks along the sheer, show the sheet position with the clew angle bisected; both fall in good position on the plan of the hull.

Clew sheet leads

So far so good. The same was done with the mainsail moved to the 2nd thwart.

Main curve at aft step
Aft sheet lead

This worked out pretty well too. The steps in the reefing process for this ketch plan are shown in the next several photos. In each one there is a metal bolt that indicates the CLR (center of lateral resistance) and an orange thumb tack the shows the CE (center of sail effort). The calculations for CLR and CE were done using the methods in Dave Nichols book. On the masonite the CE of the individual sails can be marked down (and erased, and marked down, etc, etc.), and then the combination figured.

Full sail
Jib furled
Main reefed
Main to aft step
Mizzen to aft step
Mizzen and jib alone

In light air with all three sails up (full sail picture above), the CE leads the CLR by about 6 %. The total surface area is 225. As the wind increases the first reef is dousing the jib (Jib furled above); lead is 0, area is 190. Second reef is with the main reefed (main reefed above); lead is -3% , area 160 . Third reef (main to aft step above) full main moves back to second position and mizzen is struck ;lead 0 , area 120. Fourth reef mizzen alone at second position (mizzen and jib alone above); lead +3 area 70.

As an alternative, if all sails were up and it started to blow, the loose main could be brailed, leaving mizzen and jib in configuration of photo 15 (P15 sprit 6; lead -10 and sq 105); In this setting the boat would be head to the wind and riding snug. Of note, Phil states that the lead on long narrow hulls like a whaleboat is relatively less important than on modern boats, eg fin keelers. He also feels that sprits in particular tend to have more weather helm than CE calculations would suggest, so recommends moving them forward. I'm taking a leap of faith here. I could decrease the rake of the masts to move CE forward but then the rakishness suffers.


As I said earlier,the sprit is wonderful for power and simplicity but reefing is not among its virtues. So what to do about the big main? Pete feels that once they get to about 16' sprit length they can be too unwieldy to be practical. In the proposed sprit ketch design getting at the snottier would involve standing on the the thwart to bring it in reach; volunteers? I worried enough about this to start fiddling with ways to make it easier. For example, if it could be set up with the sail in a track (or on toggled robands as in the Catspaw) and arranged so that the snotter did not have to be moved in reefing, it would be relatively straightforward. If the sprit is to remain fixed, the peak out haul has to be adjustable and the sail has to lower without fouling the snotter. In a previous article I proposed the snottier could rest on a bar athwart the mast and leave the luff of the sail separate; one of my senior sea-dog advisors gave me just enough of a look to have me drop this idea as unseaworthy. Here's an alternative; the snottier encircles the mast under the sail track.

Snotter under sail track

The next set of photos shows a 1/4 scale model to test the ideas. The sail is assumed to be in a track. Two other requirements are that the brailing line is attached to the sail and not to the mast, and that the sprit has a "spritstay" from the mast to keep it from capsizing. (The more historical method is to have a sort of halyard that attaches to the upper third of the sprit, holding it up independent of the sail. With the sprit freely supported like this and the sail in a track, the sail can be lowered and removed with the sprit standing.) The photos show the sequence of events in reefing.

1/4 scale sprit rig : full
Peak outhaul eased
Throat halyard eased
Reef points tied
Halyard and outhaul taut
Brail released

The brailing line can also serve to make it easier to wrap the sail up in a bundle.

I then did the same process on the Catspaw: photos 23 and 24 show the shape of the final stages full and reefed. the peak outhaul is attached to a ring that encircles the sprit.

Catspaw full sail
Catspaw reefed sail

I have to wonder if it wouldn't be simpler just to brail the main and drop it into the boat to reef it in relative comfort.

Next time, competing the hull.


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