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Mast location?

Discussion in 'Canoe Sailing' started by Giiwedin, Aug 27, 2005.

  1. Giiwedin

    Giiwedin Gouvernail

    Can anyone speak to question of mast location. I have an English where the mast thwart is immediately aft of a 16" extended front deck. On the other hand, I've seen a number of other sailing rigs where the mast is located at or just aft of the bow seat. What are the relative merits/demerits of each?
     
  2. Todd Bradshaw

    Todd Bradshaw Sailmaker

    Since add-on sail rigs usually allow you to play around with placement of the leeboards quite a bit, and since the typical canoe hull itself creates a fairly small amount of lateral resistance, you may or may not be able to get away with the mast stepped that far forward. The leeboards themselves are going to provide the majority of the boat's lateral plane and balancing the board position against the sail's area is going to be somewhat more important than where along the canoe's length the boards, mast and sail fall. That being said, stuffing the mast that far forward is seldom ideal from a performance and handling perspective. Canoes generally sail best with the leeboards under the sail's center of effort and pretty close to the center of the boat. This also gives the sailor the ability to easily use his weight to make changes in fore and aft trim, which in turn is a powerful fine-tuning tool for steering and helm balance.

    As well as driving force, pressure on the sails creates a certain amount of downforce. If the sail is stepped way up in the bow it tends to give the bow stem a lot of "bite" which can make steering rather peculiar, the same way a paddling canoe which is bow-heavy can be squirrelly to steer. In most cases, boats which step their masts far up in the ends had more than one sail, balancing the sailplan fore-and-aft along the hull. You might find the main mast stepped through the deck, and a mizzen stepped through a thwart or seat somewhere in the aft half of the canoe. Other configurations were sailed stern first with the big mainsail stepped close to the leading end (stern seat or deck) and the mizzen stepped through the bow seat frame or the thwart right behind the bow seat. It would be fairly unusual to rig a single-masted boat with the mast that far forward if they were serious about the canoe actually sailing well. Stepping a single mast in the bow seat/bow quarter-thwart area usually works better as it places the center of the sail closer to the middle of the boat.
     
  3. OP
    OP
    Giiwedin

    Giiwedin Gouvernail

    Thanks, Todd. Very informative. I will post photos of the English, showing placement of the mast thwart. Assuming it were possible, do you think moving the mast back to the bow thwart would make sense?
     
    Last edited: Aug 28, 2005
  4. OP
    OP
    Giiwedin

    Giiwedin Gouvernail

    Here are shots of the English 20.
     

    Attached Files:

  5. Todd Bradshaw

    Todd Bradshaw Sailmaker

    On something so nicely built, I tend to initially assume that the designer knew what he was doing and would hesitate to mess with it unless I found out that it didn't sail very well. I'd start by laying the sail out on the floor and doing some measurements to find the sail's Center of Effort and temporarily mark it with a piece of tape. Then I'd rig the boat in the yard. The C.E. will fall aft of the mast. How far aft is going to depend on the specific spar/sail/rig type used on the canoe. Once the sail is up, the leeboard bracket should be positioned and for starters, you want the boards right under the sail's Center of Effort. If the result puts the boards and the C.E. in the fore-and-aft vicinity of maybe 1/3 to 1/2 of the way aft of the canoe's bow, you're probably fine. Leeboard bracket position can then be fine-tuned during the sea trials to give the best possible handling. If, on the other hand, the sail's C.E. and leeboards end-up way forward, due to the position of the current mast thwart it might be worth trying to move the mast aft (but I'd still try it on the water first). It's such a lovely hull that I'd hate to mess with it without having a very good reason to do so. Even if I wanted to move the mast, I'd be inclined to do so by building or buying a drop-in, clamp-on mast thwart/step frame system like the Lost in the Woods Boatworks "Rigging Deck" rather than by bolting and screwing new wood to a beautiful boat.

    Rigging deck info:
    http://lostinthewoods.ca/conversion.html
     
  6. Jim Kirk

    Jim Kirk Jim Kirk

    Robert,

    Your English 20 is a very handsome canoe. I like the look of the vertical stems. I have a copy of the book "Building Classic Small Craft" Volume 2 by John Gardner which has a section on Peterborough Plank Canoes. English Models 21 and 16 are discussed. The lines and a table of offsets are given for a Model 16 I believe. There is also a dimensioned drawing of a sailing rig on a 16 footer. The mast is stepped way forward, through the bow deck with an extreme rake, 71 degrees. The boom jaw is stepped approx. 30" aft of the mast creating sort of a high aspect ratio lateen rig where the entire sail is aft of the raked mast. The drawing explains it much better than I can. The drawing shows the leeboard placed directly under the center of effort of the sail which is 68.75" aft of the bow. It is steered with a paddle. It is described by Walter Schalle, a canoe sailer in the 1920's?, as "the fastest lateen rig ever raced in the ACA". My take is that a canoe can saill very well with a rig fairly far forward as long as the leeboard is placed properly as Todd explains.

    Best wishes with your project,

    Jim Kirk
    Long Beach, Ca
     
  7. Dick Persson

    Dick Persson Canoe builder & restorer

    Jim,

    Attached below is a picture of the rig you described. I copied this rig from an old set that came with a Peterborough canoe I restored about eight years ago. That sail is about 64 sqft if I remember right. This set-up is indeed very fast. I have to admit I almost scared myself silly the first time out, not having the leeboards properly positioned. With a different set of lee-boards and better prepared this rig sails very well even though the full mast is stepped way forward.

    Cheers
    Dick Persson
    Headwater Wooden Boat Shop
     

    Attached Files:

    Last edited: Sep 3, 2005
  8. Dick Persson

    Dick Persson Canoe builder & restorer

    Robert,

    Nice canoe. I echo what Todd said.
    I saw John Hupfield from Lost-in-the-Wood-Boat-Works demonstrate his “rigging deck” a couple of weeks ago. A very nice solution, easily and quickly rigged, one of the best solutions I’ve seen. Well worth to take a look at.

    Cheers
    Dick Persson
    Headwater Wooden Boat Shop
     

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