How much weather helm with a gaff rig?

[robertg1]

Desiring a gaff rigged craft of working boat heritage, I recently found one for sale that I like. However, when I undertook a test sail I was disappointed at the amount of weather helm; even though I was expecting some.

We were under full main, staysail and jib on flat water (offshore wind) in a wind that was initially F3 and increased to F4 and possibly the “easy end” of F5. The boat was stiff and not heeling significantly. The mainsail was quite full and could have been flattened. The boat has a large powerful rig with the boom overhanging the transom.

The tiller did not need to be pulled far to windward but significant force was required to steer a straight course, resulting in me feeling the need to lash the tiller to reduce the strain on my shoulders. There was a small amount of cavitation from the rudder when the wind was at its highest.

My question, to those with gaff rig experience, is have I got to live with significant weather helm if I want to sail a powerful gaffer?

 

[dur]

Hi there

The answer is something like not nesessarily but probably

My experience is only with small gaffers and none which would carry full sail in F5 and not be heeling significantly. But yes as the wind gets up weather helm becomes more significant. You have a big powerful mainsail on a long boom - the centre of effort is a long way back and almost certainly moves further aft in a stiff wind. But good sail setting should help as with any boat. So in those conditions (apart from a reef) I would have a lot of luff tension and the peak very tight plus some tiller lines and/or a heavy bungee to relieve some of the load. After that just enjoy the fact that you are so much faster than the awbs off the wind!

 

[binch]

weather helm

My early boats were gaffers.
The Lowestoft smacks, whether Brixham or Dundee rigged, all carried weather helm. My father (a fishing skipper under sail) told me that this was because the ship needed a lot of effort to steer, and this way they could rig a tackle and steer effortlessly by just hauling or checking the tackle.
I later had a largish broads cruiser with enormous gaff rig. She was perfectly balanced in a force 3 but as the wind and speed increased so the CLR moved forward and she became hard-nosed and a bit of an illegitimate child.
Among the broads cruisers it was quite common for helmsmen to lose control in a strong gust and go up the weather bank.
Gaff rig is more fun to sail but has its disadvantages.

 

[Easticks28]

My 28' Broads cruiser is gaff rigged and very well balanced, exhibiting just enough weather helm to give 'feel' to the helm. The rudder is a large balanced affair, with one third of its area before the stock.
When I first started to sail gaffers having previously done all my sailing in bermudans, I found that I was constantly over sheeting the main - then I found out what weather helm is! Try freeing off a bit - or reef earlier.

 

[oldfrank]

Gaff rig isn't any different from Bermudan in terms of weather helm. It's quite simply how far aft the centre of effort of the rig is behind the centre of lateral resistance of the hull. Think how sailboards are steered by moving the rig fore and aft. Too much mainsail and the weather helm will increase. There is however a 'googly' in hull shapes. Modern racing boats tend the have a straight line along their waterline roughly between the hull and the shrouds. If the hull is full here (common in many Broads boats) the boat will develop more weather helm as it heels - it may even get shorter (and therefore slower) if the bow isn't properly ballasted. Do not rule out internal balast if the hull isn't going to plane. OF

 

[cliffordpope]

I have had quite a lot of practical experience correcting weather helm on my 21 foot cutter.

For a given hull, 2 factors interplay:

1) The position of the Centre of Effort. ie how much sail there is, front and back

2) The position of the Centre of Lateral Resistance. ie the lateral underwater cross-section.


Xenia originally had dreadful weather helm. Firstly this was caused by an original (ie 1880) design fault placing the mast too far forwards. I moved the mast back 3 feet, which made a big improvement. Then I restored the bowsprit to something nearer its original length, and shifted a lot of ballast further aft.
More recently I shortened the boom by 2' 6" and tried a smaller main.

The result is now near-perfect balance. On most points of sailing she needs very little rudder at all. In a stronger wind she does tend more into the wind, but that's inevitable and desirable because as she heels a third dimension comes into the CLR/CoE interplay, and the CoE exerts more leverage because it is now out-board.

Looking at pictures of victorian yachts, they often had impossibly long bowsprits - 10 foot overhang on a 20 foot hull was not unknown. So reducing that to a mere 7 foot to make the sail more manageable inevitably means making some corresponding alteration aft.