Nigel Irens on Booms

I just wrote to a guy in Australia who is about to build a ROMILLY, who asked me what my thoughts were about whether to sail the boat boomless or with a boom (which runs past the mast and rests against it).

I’m copying you with my reply in case you think it will be helpful to other people who visit your website (at least provoke some debate on the subject !) Nigel

I know Ed Burnett prefers the boomed version, but I think I still come down in favour of the loose footed sail. The sail set on a boom is great when the boom and sail are to leeward of the mast, but when they are to windward the luff is horribly flat – even negative, which pretty much negates any hope of decent flow round the low-pressure side of the sail.

We have that set-up on the 38 ft ROANNA – which is a three-masted boat with a fairly extreme amount of boom running out forward of the main mast. I remember sailing her next to another boat and noticing how the luff of the sail on the ‘wrong’ gybe was running off the mast as the sail draped over it. We tried hauling on a pair of lines rove through the two luff reef cringles, so that we hauled put some shape into the sail. The difference was very surprising and we simply sailed away from the other boat.

The moral of the story is that if you decide to go with a boom you might think about making provision for doing the same thing. The result looks a bit strange because the tack of the sail cannot be hauled aft (as it’s attached to the end of the boom), but it does work well.

To set against all that it’s true that you can get much more out of a ROMILLY or ROXANE with a loose-footed sail when sailing off the wind by setting a bearing out spar. This should run diagonally so that the spar is both bearing out the sail and also stopping the clew from rising – which of course puts too much twist in it. Without this bearing–out spar you’ll find that the luff is fluttering and yet the leach is over sheeted – not at all efficient as it sets up some mighty weather helm.

The situation is made worse by the fact that the shoal draft on these boats means that the rudder is a rather unpromising ‘barn door’ shape. This was improved when we fitted an end-plate to the bottom of the rudder, but if you find you have the tiller up under your chin when there’s a bit of breeze on the quarter, then you should be able to solve this by using the bearing-out spar to un-twist the sail and get the luff to power up. Doing so puts the centre of effort forward again (where it belongs) and lightens up the helm. Big rudder angles are, of course, very draggy, so it is really important to work on ways of reducing the work the rudder has to do.

    1. Dermot Cox says:

      I have recently taken over an early Romilly with a loose-footed main. My first coastal trip (Dartmouth to Solent) involved a lot of sailing with with the wind on the quater. Ended up with the mizzen brailed to reduce weather helm. Got me thinking about a bearing out spar, which your text above seams to confirm. Where do you recommend positioning the inboard end?

    1. Philippe Galland says:

      I sail my Romilly (Augustine n°7) generally singlehanded so the boom is an undiscutable necessity. Maybe there is something I dont understand but it seems to me that the solution of the problem is to set the tack of the sail, (boom or not) level to the mast. Its perfectly possible even with a boom. I use the same block to down haul the boom that the one which was used to seize the tack of the loose footed sail: The tack of the boomed sail is exactly at the same level than the loose footed one. It’s obvious anyway that it has a better look this way on starboard tack.
      About limiting the twist and going downwind with a boom, I’m making some experiment and will talk about it when it will be done.

    1. Martti Halminen says:

      I’ve been experimenting with a boom on my Roxane (Rx9, ex-Mischief). Works nice when using two separate downhaul tackles: the front one at the forward end of the boom, so upwind the sail geometry is the same as loose-footed. For reaching or running I let go that one, and use the other one attached about one meter farther aft on the boom, making it a balanced lug, with some vanging effect.
      - needs some kind of sliding truss arrangement to keep the boom at the mast when raising the sail.
      - not quite perfect, the reef lines must be cleated on the boom. Still, much easier than reefing the loose-footed sail, especially with lazyjacks.