Swept-Back Spreaders

I just wondered what you think about the point the captain of the Morgan’s Cloud makes here about swept-back spreaders:


John Harries is a good friend and very experienced seaman and his comments make sense in a certain context. However, swept spreaders make sense in several situations. First, on higher performance designs which do not often run square with the wind, and where the extra roach and power more than makes up for lost projected area. Next, with small degrees of sweep, like eight degrees, which can be very effective in stabilizing the mast and reducing rig weight at small off the wind penalties.

Where I agree with John is on conventional slower designs with heavily swept spreaders, and triangular (as opposed to  roachy) mainsails.

Posted by Steve Dashew  (August 14, 2009)

4 Responses to “Swept-Back Spreaders”

  1. Henry Rech Says:

    Hi Steve,

    Could you talk about your experience with a swept-back spreader rig in Sundeer and Beowulf dead running in heavy conditions?

    Is the risk of unintentional gybes higher with a constrained boom angle, particularly where waves are pushing you about?

    Is there an increased risk of broaching/rolling having to head across the waves in heavy conditions?

    Is it imperative to keep the boom off the shrouds? Did this present any problems?



  2. Steve Dashew Says:

    We never run square with our designs. That is uncomfortable due to rolling and usually slower than coming up 15 to 30 degrees. In heavy weather it is equally important to keep from running square.
    We usually vang the boom a couple of feet off the cap shroud,but allow the upper third of the main/mizzen to rest against the caps. We use UHMW chafe gear on the battens.

  3. Henry Rech Says:


    I would imagine rolling combined with a little bit of a wave push or wind shift can also increase the risk of an unintentional gybe.

    I remember many (many) years ago in a Sydney Hobart hard running with a spinnaker and blooper up (never see them anymore) in 25-30 knots off the coast of Tasmania. There was only two of us on deck (being early morning and breakfast time). The helmsman lost concentration for a second – for whatever reason the wind ended up on the lee quarter and pushed us into an involuntary gybe. Over she went, both spinnaker and blooper beginning to fill with water – the yacht was also being held over because the main boom was being constrained by a boom preventer. I managed to scramble across a near vertical deck using the head of a crew member emerging from the main hatch as a stepping stone (what else could I do?). I managed to snap free the preventer, over went the boom and up she came (the halyards where also let go) – dragging a tangled spinnaker and blooper in the water and many tons of water of course.

    Maybe it ain’t such a good idea to dead run in heavy conditions (and this was on a yacht with square spreaders).


  4. Steve Dashew Says:

    That’s it. In our experience it is always better to come up from a dead run inn nice weather (better VMG and ventilation), and in heavy going much more controlled.