A question of weather helm.

[johnalison]

It's important to differentiate between a heavy helm and weather helm. A boat like the Neptunian with an unbalanced rudder is always going to have a lot of load on the helm as soon as the boat is out of balance whereas one with a balanced spade can have a large amount of correction applied to correct weather helm with minimal load on the helm. To accurately assess the issue you need to be looking at the angle of rudder applied not the weight

That is a distinction that is seldom made. As I understand it, properly, weather helm describes the angle at which the helm has to be to maintain a straight course, with no reference to the amount of effort to keep it there, but in popular parlance it has come to mean the situation where some effort is needed to hold it there. 'Heavy helm' might mean the same, but can also refer to a helm that is resistant to being moved generally, even under motor.

I don't think it is worth being purist about it now that the horse has bolted, but it would help if people made it clear what they were describing. Just to confuse things, I could say truthfully that my boat carries a marked weather helm under some conditions such as a close reach, but in these conditions it carries no additional weight, in fact I can usually release the helm and the boat will track in a straight line.

 

[Dockhead]

The concept of balancing the centre of pressure of the sails to the centre of lateral resistance of the keel and hull is well understood. On some boats it can be easily demonstrated in light winds. You can actually steer a boat even tack and gybe.
However as soon as the typical keel boat heels, much more powerful forces come in to play. The asymmetry of the hull in the water and the drive of the sails becoming outboard of the hull cause huge weather helm tendencies. To the point of losing control. The only answer is less heel in stronger winds. This means less sail usually starting with reduction in jib size but also demanding reefing of main. Op observed furling the genoa helps the weather helm even though it should move the centre of effort aft and contrary to what one might expect (and find in light winds) ol'will

Different hull shapes behave differently, but this is the direction I would go in.

On my boat -- different generation boat, different hull form, so YMMV -- weather helm is an almost linear function of heel, and is much less sensitive to fore-aft sail plan balance, than to heel angle. I get almost as much weather helm with just the jib up and no mainsail at all, if I'm overpowered.

Then the big factor is drag of the sail plan. Baggy sails will give you more heel and more weather helm right there. Good sails needed to be trimmed right -- generally flatter, the more wind. So try to get as much drag out as possible with sail trim.

Then one biggie -- overtrimming the main will instantly give you weather helm. When you're on the verge of needing a reef but not quite there yet, it's very good to flatten the mainsail (more outhaul tension, more vang tension) and feather it a bit -- UNDERtrim it just a bit, slackening the mainsheet, but not so far that it flaps.

I don't like big overlapping genoa sails which are really good only in a very narrow range of conditions and point of sail. These can produce a lot of drag and make the boat unpleasant to sail in a lot of conditions. You can't really reef them without ruining the shape. If you have higher aspect jibs in your sail locker, you might want to try them. If you don't, you might want to acquire one. On my boat I have a 120% yankee (I'm a cutter, so there's also a staysail) and a 95% blade, both in carbon laminate. I hardly use the yankee except for racing in light conditions. The blade has all of the power of the yankee in most conditions, and much less drag. So I heel less, go faster most of the time, point higher. The yankee is only beneficial in really light winds, and sailing off the wind. The genoa on your boat might possibly be a part of your problem.

 

[Dockhead]

My SR25 has weatherhelm and anyone new to the boat .. I tend to let guests sail her .... usually comment they need to depower the main .... OK - go ahead I say ...
But WH is still there ??

Yep.

Why ? Because the genny has too much overlap .. in light airs - its fine but as soon wind starts to pick up ... start furling the genny to have its CoE move forward .... its that pronounced that you can leave the main unreefed ....

3 or 4 yrs back - I finally decided to replace the genny with a shorter foot version ... what a difference ... speed is same or even more as the weatherhelm has reduced letting the rudder have less drag etc.

Exactly my experience.

 

[Birdseye]

Unless I am having a brain fart " The only thing that helps is to furl most of the genoa away to move the overall COE forward, " is completely 180 degrees wrong. Furling the genoa will move the C or E of the sails sternwards

 

[Refueler]

Unless I am having a brain fart " The only thing that helps is to furl most of the genoa away to move the overall COE forward, " is completely 180 degrees wrong. Furling the genoa will move the C or E of the sails sternwards

EACH sail has its own CoE ....

You are referring to the OVERALL CoE of Genny and Main combined.

Yes as you furl a genny in its INITIAL stages - the CoE will move aft - but as the genny furls more - the nett addition of its CoE and the Main will move fwd.

Whether that's right or wrong does not change the fact that furling the oversize genny DOES tame weatherhelm on many boats - particularly older boats where gennys are THE power force ..

A good example other my Sunrider 25 .. is that Macwester 26 and its later 27 ... a boat that is notorious for gorillas armpits of weatherhelm ! So often you see them out there with reefed main and big genny .. and skipper complaining he's fighting WH. GET THAT GENNY in ... and enjoy life !!
The 27 .. pretty well same boat except they shortened the boom ... some had mast height raised - but most not. Did it cure it ... no.

When I was in UK ... a MW 26 used to be berthed next to me at one place. We had various chats about both our boats having WH ... so I used to repeat to him - try furling the genny BEFORE reefing main ... eventually he tried it and I noticed that he often had his genny furled after that !

 

[Porthandbuoy]

Unless I am having a brain fart " The only thing that helps is to furl most of the genoa away to move the overall COE forward, " is completely 180 degrees wrong. Furling the genoa will move the C or E of the sails sternwards

Furling the genoa moves the COE of the genoa forward thereby moving the overall COE forward and negating weather helm (I wish). Furling the genoa completely away leaves me totally screwed as the COE is all aft of the centre of lateral resistance (CLR).

 

[Refueler]

Furling the genoa moves the COE of the genoa forward thereby moving the overall COE forward and negating weather helm (I wish). Furling the genoa completely away leaves me totally screwed as the COE is all aft of the centre of lateral resistance (CLR).

It initially moves aft slightly but then progressively moves fwd until the overall area of the genny is small and CoE forces are so small as main then takes over and CoE overall moves aft.

If you are getting to the range of furling that genny is losiing its effect - main should already have been considered for reefing ..

For my boat : Initially furl up to 15% of genny - then main first reef ... then genny again until probably 50% is away ... by now I am thinking of why am I out here !!

 

[[194497]]

Is there not something about where the draft is in the sails that has a big effect on weather helm? Not just how deep the draft of the sail is, but whether it's nearer the luff or the leach?

 

[Supertramp]

There is lots of good advice here to experiment with.

Currently closereaching in a light wind and I just removed a little weather helm with minor adjusts to the genoa and mizzen.

Find a steady wind, set up your autohelm and experiment. A long keel, heavy boat with modest sail area will not respond like a race machine, but long keel hulls have a sweet spot where the rudder is central and they slip along. Usually avoiding over sheeting everything helps - I think the term "full and by" applies.

 

[Birdseye]

EACH sail has its own CoE ....

You are referring to the OVERALL CoE of Genny and Main combined.

Yes as you furl a genny in its INITIAL stages - the CoE will move aft - but as the genny furls more - the nett addition of its CoE and the Main will move fwd.

Whether that's right or wrong does not change the fact that furling the oversize genny DOES tame weatherhelm on many boats - particularly older boats where gennys are THE power force ..

A good example other my Sunrider 25 .. is that Macwester 26 and its later 27 ... a boat that is notorious for gorillas armpits of weatherhelm ! So often you see them out there with reefed main and big genny .. and skipper complaining he's fighting WH. GET THAT GENNY in ... and enjoy life !!
The 27 .. pretty well same boat except they shortened the boom ... some had mast height raised - but most not. Did it cure it ... no.

When I was in UK ... a MW 26 used to be berthed next to me at one place. We had various chats about both our boats having WH ... so I used to repeat to him - try furling the genny BEFORE reefing main ... eventually he tried it and I noticed that he often had his genny furled after that !

Yes and no. What matters is the combined C of E plus the combined force that acts through it all balanced against the forces developed by the hull at a particular heel. Simple Newtonian mechanics. So the effect of furling the genoa will likely move its C of E forward and it will also reduce the force acting through that CofE because of reduced sail area. However II still dont think that would normally reduce weather helm unless maybe the OP has a boat with the old style enormous genny and small main all well forward on the deck. Could be the case I suppose since he mentions a mizzen which is the sort of thing you only find on old boats with big genny small main rigs.

As it happens I spent some time this week, whilst waiting for a race start, fiddling about with sail settings to get my boat to track true upwind and without a hand on the tiller. Its a factional rigged single masted modern sloop with a wide arse and I found that hard on the wind with the genoa completely unfurled and sheeted well in I needed to free off the main to the point where the luff started to bubble before it sailed straight (and fast as there was no rudder drag).

Only reason I mention this experience is to suggest that the OP does exactly what I did and experiments starting with freeing off the main. I have in the past and on earlier boats put spacers in the forestay or altered the existing ones to get the right amount of weather helm but thats a last resort when the sail tweaking doesnt work well enough.

All this is part of the fun of owning a sailing boat. We should feel sorry for the mobo guys who just drive to the marina and then just drive a boat.

 

[Baggywrinkle]

On my last boat which was a 36ft fin keeled AWB with a spade rudder, excessive weather-helm was usually a precursor to the boat rounding-up, the helm was basically fighting the boats tendency to escape the sideways and downward pressure from the sails by spinning head-to-wind and letting everything pop upright again. This tendency was reduced with new sails, and swapping the 130% genoa for a 110% one helped a lot.

Reducing sail always solved the problem - but that meant reefing both sails. It's tempting as a cruising sailor to just reef the genny because it's roller furling and easy, but my main needed to be reefed too - often left too late because it's hard work in comparison. Sailing the boat more upright with balanced sails reduced weather-helm to almost nothing - even in strong winds. I generally sailed to a speed ... anything above 7 knots and I reefed, trying to hold an average speed of 6 knots was comfortable for the boat and the crew.

On my current AWB, all the sails are on electric furling with electric sheet winches, so I adjust the sail size all the time to maintain a cruising speed of somewhere between 7 and 8 knots where she seems very happy, she sails without much heel and the helm is light. I've become much more of a tweaker - and without wanting to start a roller furling/stack-pack debate, my new vertically battened, roller-furling main is a dream.

When all the telltales are flying cleanly, and I'm maintaining a good sail shape, and the courtesy flag under the crosstrees is streaming cleanly in the slot, the sail luffs are not flapping, and she's doing 7-8 Knots - that's good enough for me and I'm very happy. If she start's approaching 9 knots, I reef to bring the speed down.

 

[Dockhead]

On my current AWB, all the sails are on electric furling with electric sheet winches, so I adjust the sail size all the time to maintain a cruising speed of somewhere between 7 and 8 knots where she seems very happy, she sails without much heel and the helm is light. I've become much more of a tweaker - and without wanting to start a roller furling/stack-pack debate, my new vertically battened, roller-furling main is a dream.
. . .

Being able to easily and finely regulate sail area is a profound advantage of in-mast furling.

In ideal conditions of course a full batten main with a good bit of roach is more powerful. But in changing conditions with the wind going up and down, the full batten main will often be stuck with too much or too little sail up,

 

[Dockhead]

There is lots of good advice here to experiment with.

Currently closereaching in a light wind and I just removed a little weather helm with minor adjusts to the genoa and mizzen.

Find a steady wind, set up your autohelm and experiment. A long keel, heavy boat with modest sail area will not respond like a race machine, but long keel hulls have a sweet spot where the rudder is central and they slip along. Usually avoiding over sheeting everything helps - I think the term "full and by" applies.

Don't forget you need a little rudder angle when going upwind, even close reaching. Angle of attack of the rudder is what produces the lift which counteracts the sideways force vector from the sails. Too much and the rudder is acting like a brake. Too little and the rudder doesn't "fly", and the keel won't, either.

For the same reason a small amount of weather helm is desirable.

 

[Supertramp]

Don't forget you need a little rudder angle when going upwind, even close reaching. Angle of attack of the rudder is what produces the lift which counteracts the sideways force vector from the sails. Too much and the rudder is acting like a brake. Too little and the rudder doesn't "fly", and the keel won't, either.

For the same reason a small amount of weather helm is desirable.

Thanks, I think that's what I meant by sweet spot. Good to understand the reason.

 

[Tranona]

Being able to easily and finely regulate sail area is a profound advantage of in-mast furling.

In ideal conditions of course a full batten main with a good bit of roach is more powerful. But in changing conditions with the wind going up and down, the full batten main will often be stuck with too much or too little sail up,

Pleased to see that I am not the only one that appreciates the flexibility offered by in mast mains, particularly in the modern fractional rigs with smaller jibs giving roughly 50/50 split of sail area. I have never understood why a slab reefed main where you only have three (or maybe 4) choices of sail area and the first reef is typically 25-30% reduction after a lot of sweat pulling bits of string or even going to the mast to fight with hooks or clips to hold the tack down.

Much of our coastal pleasure sailing is in winds of between next to nothing and 25 knots and within that it is the 15-20 knot range that gives the best sailing but also on many boats it is the range where maximum sail area becomes too much. My last boat was a 2015 Bavaria 33 with in mast and particularly after I replaced the original main with one in Vectran it was always easy to adjust sail area to match conditions. A roll or 2 in either the main or the jib were easily achieved but just pulling one line for each from the cockpit. Trimming was easy to achieve a balanced helm with a touch of weight on the wheel. I sailed it on my own most of the time and it was really satisfying to set it up turn on the AP set to sail to wind.

 

[The Q]

I know your boat is comparitivly large, compared to anything I sail now, but how much excess weight have you in the stern. Lockers full of " stuff" will tilt the whole boat, pushing the sail area Aft..

In my little 17ft sailing cruiser I had to keep the aft lockers empty, and put the outboard in the bow to sail well..