Will a boat trimmed by the head have increased weather helm?

[rkarakai21]

Since purchasing our 1982 Roughwater 33 sloop a couple years ago and sailing her a few hundred nautical miles with her I'm starting to identify some characteristics about her sailing.

She sails well overall for a 15000 lb boat with a fairly traditional hull shape. Average speeds are quite decent even in lighter airs with her 150 Genoa fully rolled out, or our old used spinnaker. One thing thats nagging me however is that she seems to develop more weather helm than she should in moderate wind, say 10-15 knots on the beam or close hauled, There is a hell of a lot of pressure on the rudder and I have tried outhauling hard, vanging tight, etc, to get the main flattened out, but it's an older main, and it's trimmability is debatable. Its not totally bagged out, but getting there. Apart from prematurely reefing, which does work, but then leaves me underpowered I'm not sure what else to do.

Since we purchased the boat I've noticed she is significantly down by the head, the stern waterline is about 3 inches above the water and the bow waterline is usually about a half inch under water, so a half inch up the bootstripe. This is in cruising conditions with our fiberglass dingy on the bow, and the water tank full.

I wonder if this could be causing or contributing to the excessive weather helm.

She was built with a 12 Ga stainless water tank under the v-birth and we have 100 feet of 5/16" chain and 120 feet of 5/8" nylon rode in the chainlocker.

The previous owner told me she used to have much larger stainless steel fuel tanks in the stern but he had issues with them and downsized significantly and went to plastic tanks. I'm not sure the size of the previous tanks, but from the vacant space in the stern I can see they were quite a bit bigger.

I wonder if changing the fuel tanks alone could have thrown off her trim that much.

I plan on installing two fairly large steel water tanks in the stern before heading offshore and probably deleting the v-berth water tank, in favour of more storage space for sails. Hopefully she will balance better when shes sitting on her designed lines.

[wholybee]

150% might be too much in 15 kts. You mention outhaul and vang, what about the traveler? Is the boom close to the centerline, or have you traveled it to leeward? If you travel to leeward or ease the mainsheet to the point the main is luffing, and you still have weather helm, the 150 is just too big for conditions. If it is only rarely you need to roll it up, that would work, or you might consider a 130. Old sails, both the main and the jib, don't help either.
I don't know if the bow being overloaded would cause weather helm or not, but it will adversely affect the performance. It sounds like your imbalance is large, and that needs to be fixed. Has it been repowered with a lighter engine? Is the water tank full when you observe this? I doubt 100ft of 5/16 chain could raise the stern by 3 inches, but a 33' boat would be fine with 1/4" HT.

[s/v Jedi]

Most of the weather helm is caused by the asymmetrical shape of the hull under water when heeling.

The more heel, the more weather helm. So flattening the sails reduces drag which reduces heel which reduces weather helm.

With the bow down I don’t think it makes a lot of difference in hull shape under water? You may need new sails or reduce sail.

[Bowdrie]

William Atkin, a prolific designer of what might be called "wholesome boats", said in his writings that one should not trim a boat down by the head.
But he didn't expound on it.
IIRC, Olin Stevens, when S&S was heavily involved in Americas Cup design work said that the ideal amount of weather helm was when you were carrying about 3>4 degrees of rudder angle.
Less than that was getting close to neutral>lee helm territory, reducing lift, and more than that just added drag.

[fourlyons]

Trimming a boat down by the bow is functionally equivalent to raking the mast forward, this brings the center of effort forward relative to the center of lateral resistance. All other things equal, this will reduce weather helm.

[Lee Jerry]

In most dinghies, weight forward (trimming by the bow) does cause the boat to turn into the wind (i.e. give weather helm) and weight aft turns it down (lee helm). I assume this would apply to larger boats too. (But note this is a generality; it may not apply to all dinghies, so then wouldn't be all bigger boats either.) Thus, the trim could indeed be contributing to your weather helm.

You should be able to test this somewhat easily - reduce the trim by removing weight from the bow (temporarily remove the dinghy, empty the water tank, move the anchor and rode) and/or add weight to the stern and see what it does. I wouldn't think it would take too much weight change in a 33' boat. People in the cockpit might be easiest, but anything would work (that is secure).

But there could be other factors too, some mentioned above.
Obviously, better sails would probably help.
Have you tried raking the mast forward?
Do you have leach telltales on the sails, especially the main, to help with proper trim? Ease the vang to get them all streaming on a reach.
How much heel do you have when the weather helm occurs? In addition to the immersed shape effect mentioned, heel also moves the CE of the sails outboard, increasing that yaw moment (to weather).
I see your boat is full keel with attached rudder, but you may be able to do something with the "foil" shapes.

Finally, do you know if any other people have the same issue with their boats? Some boats just aren't balanced well by design...errrr, in the design, by accident. A J30 for example goes to weather fairly well balanced, but on a reach (especially with the wind up) the tiller becomes a bear. Moving the rudder aft a couple inches solves the problem (but isn't class legal).

[hpeer]

A older mainsail often has a shrunken bolt rope. This bags out the sail. I had that problem and various sailmakers did not comment on it. A friend of mine pointed it out as she had the same problem. Her sailmaker dealt with it for her, but he would not do mine as it was to bug for his capabilities. It can be resolved by cutting the stitching between the bolt rope and sail and then stretching the bolt rope.

I was able to do this on my main. I put the sail on a lawn and stretched it between two poles. It took a lot of effort and patience, but when it went it ran about 6” in a flash. It made a big difference in the shape of the sail.

If your main is that bagged out you have little to loose by trying. Or maybe a loft will do it. It will have to be restitched anyway.

[Sailor Sailor]

Although we have different types of sailboats, my Sabre 34 does the same thing - sails bow down and gripes into the wind on a reach in gusts. Reefing and easing the main and flattening it with the vang seems to help. Occasional gusts will still cause the boat to heel more and head up. While this tendency makes it harder to steer, the boat speeds through the water at hull speed or faster when surfing on waves. I think it is a design feature and weight distribution would be unlikely to have any great effect.

[SailingHarmonie]

The amount of bow-down trim you describe sounds VERY large for a boat of that size. Three inches up at the stern is HUGE for a 33 foot boat. ASSUMING that the waterline as painted today is actually correct for the designed water line, that is worth fixing. Bow down trim does not cause weather helm, but it does cause other problems.

It is far better to remove weight from the bow than to add weight at the stern. A boat that is in correct trim, but with lots of weight at either end is very prone to "hobby-horseing" which can totally kill your speed in a chop as all the boat's energy gets sucked out and transformed into moving up and down instead of forward.


The single largest contribution to weather helm is heeling. This is frequently attributed to the changing shape of the hull. While true, this is not the major effect. When a boat is heeled, the center of effort of the sails moves far off to leeward, while the center of resistance to forward motion stays under the hull, and even moves a bit to windward. Imagine looking straight down on a boat that is heeled far over with the water pushing backwards on the bow, and the wind pushing forward on the middle of the sails. There is a large turning moment into the wind. This is the major cause of weather helm on most boats. Better sail trim give more drive, and less heel. Sometimes the effects of small changes can be dramatic when close hauled.

Based on your description of your sails, this is the place to start to solve youre weather helm problem. You do not mention a cunningham, or halyard tension. Those are important in depowering the main. Position of the traveler is key as well. With a well managed traveler and mainsheet, the vang shouldn't enter into the equation when close hauled.

Or, you might just need new sails... or your rig might not be tuned properly...

Have you ever talked about this issue with a sistership owner? Some boats are just not well balanced.

[Cheechako]

Hull shape alone can cause those issues. Been there done that with one boat. On a close reach, that boat, when brand new, new sails, actually stripped the cable clamp on the rudder quadrant the force was so bad! It was an odd hull shape.
Many older designs have significant weather helm issues, some of Bill Garden's designs IME.

But first thing I would try is sailing with one reef in the 15 knots of wind. See what happens.
Bow down could exacerbate the issue I imagine if the 'wetted shape' changes too much. Does the boat have a sharp entry on the hull? It may be digging in and wallowing, acting like a bow rudder a bit.
The boat I mention above had a fine deep sharp entry forward of the keel, but wide flat aft sections and a fairly deep keel.
Kinda like this:

[Tedd]

Originally Posted by rkarakai21

Since we purchased the boat I've noticed she is significantly down by the head, the stern waterline is about 3 inches above the water and the bow waterline is usually about a half inch under water, so a half inch up the bootstripe.

I can't be sure without looking at the details, but that full keel suggests to me the possibility that the way she sits in the water could move the center of lateral resistance forward from where the designer intended. Which, of course, would increase weather helm.

[Cheechako]

I remember when those boats came on the market. I kinda liked it viewing one in Seattle. IIRC they have cement encapsulated ballast? Very old school design and you may just be experiencing the typical weather helm for that style of boat: keel attached rudder, a bit narrow, double ender with fairly symmetrical ends.
I almost bought a Bill Garden edge glued white cedar double ender which was very similar, but on a test sail it had terrible weather helm. Try a reefed main to find if it's just center of effort issues.

[Benz]

Both my light reading and experience push me toward thinking that bow-down will cause a full-keel boat to gripe.
I would absolutely try to get the stern down--if the boat was designed to have bigger tanks aft, then the water tank forward was designed to balance that. Of course the poster who suggested keeping everything midships is right--but that's an ideal not always achieveable.
It IS wonderful what new sails will do; maybe trimming the waterline AND getting better sails is the solution.
I can mitigate weather helm on my boat by carrying a big jib while reefing the main, and by easing the mainsheet and cracking off a little, if I have sea room.
Every boat is different, so these are just general statements.

[DEAN2140]

I am not sure about the bow/stern balance, but vanging tight will increase your weather helm, not reduce it.This doesn't flatten the main, it tightens the leach. The outhaul has minimal effect. If you have an adjustable backstay, use it to bend the mast and thereby flatten the main.

Some boats have weather helm because of the placement of the mast too far aft. I had this problem with my Norseman 447 and when I pointed it out to the designer, Robert Perry, he agreed, but blamed the manufacturer who dictated its placement for interior design purposes.

[Kd9truck]

If your bow is down at anchor you’ve got a weight balance issue that I would resolve first. If your sails are baggy yes you will have more weather helm. Your vessel is fairly heavy so in theory you should be able to sail with more wind than a lighter vessel of the same LWL and LOA.
Where is the water tank and how much? And to that point what was the size of your fuel tankage? At that size vessel your sail inventory might be wrecking your balance and the blown out/baggy sails are accentuating the balance problem.