WEATHERHELM

As it affects Eventides and some other Y/M designs.

(can be applied to many other designs too!)
 

Since first designed, the Eventide has suffered from excessive WEATHERHELM, i.e. the need to pull the helm hard up towards the upwind side of the boat when sailing anything other than downwind. I must point out that some weatherhelm is needed, so if things do go wrong and you let go, the boat will naturally round into the wind and stop. If at present this force is so strong that you have to lash the tiller up to hold a course, the weatherhelm is too strong. Or if one of the opposite effects takes hold, i.e. the boat continues in a straight line or bears away to sail down wind, then things are sadly out of control, your boat has a bad lee helm and must be corrected before an accident ensues. Luckily, our boats have been designed with weatherhelm, so unless something drastic has been altered it is unlikely this will worry us. (If it does, speak to me  A.S.A.P.!!)


What we are looking for, when sailing close to the wind in a force four, under our working sail i.e. main or Genoa, there should be a reasonable amount of weatherhelm, a child of about ten years of age should be able to steer the boat without a struggle, an adult just resting his hand on the helm with a slight pull up wind. Letting go of the helm should result in a immediate, slow turn to windward, until she stops head to wind with the sails flapping or tacks and stops 'hove to', still in water. Yours doesn't? Two hands on the tiller, foot braced to the leeside? Won't sail with helm tied slightly to windward?.....

LETS SEE WHY.
Weather helm is caused by the sail areas centre of effort being too far behind the hulls centre of lateral resistance. Finding the centre of sail areas can be done, in theory, by finding the centre of both sails, and drawing a line between them and calculate how far along that line the centre should be in comparison to the size of the sails. It is a little  more difficult than a simple measurment, as we have to think in three dimensions, not a flat sheet of paper.  But starting in 2 dimensions is good.


Calculating the approximate two dimensional centre of lateral resistance of the hull is determined by cutting out a drawing of the underwater section of the hull from a piece of card and balancing the resolution a knife edge, by moving the shape 45 degrees either way as well as 90 degrees to the water-line you can find the actual centre of lateral resistance. There is, however a large area of error, due to the fact that we have been again working in two dimensions, i.e. we have not allowed for curves in sails or the fact that the boat will also be pitching, rolling and yawing, so any result you obtain must be treated as approximate only.


This was only part of the problem that faced the designer, therefore most designers worked on the side of safety and most ended up with far more weatherhelm than is absolutely necessary. 

The Eventide 24/26 should sail at around 15 degrees of heel and carry full main and Genoa in a force four wind. Look over the side you should see about 6" of hull still clear of the water, if not try adding weight along the centre line of the boat, lead blocks, painted iron pigs or gravel sand in strong poly bags. Then take for another spin, I think you will be pleasantly surprised, if this works, fix it all in a position until refit time.  most early Eventides are under ballasted, the plan weight has increased on a 24, from 560ld to excess of 1020lb now!

Well we have tried all the above and we have had some success. We now have to decide, do we live with it as it is or do we continue, if we decide to go further we must  wait till we take the boat out of the water and be prepared to do some work. If you have an early boat, pre 1973, with lighter ballast and you added ballast on the inside, and it worked, now is the time to look at the question of weight and add that weight to the ballast keel. This puts the weight in the best position, on the bottom and also deepens the keel by about 3", which will give the boat a better bite in the water, as per the later editions of the plans.

A 3" to 4" deep, steel box filled with steel and cast iron and bonded with cement will weigh somewhere around 300-400lb. A cast lead section to bolt on to your existing lead keel of the same dimensions will weigh about 500-600lb.
Do not mix your metals, (steel with steel, lead with lead). Note, it is not advisable to use stainless steel for any underwater fittings or fixings, as stainless only keeps it good qualities, when in contact with air.

Now the trick is to fit the box that you have made between the hull of the boat your existing ballast keel, don't be put off, it is not as difficult as one might think. This has been used on 'Bluenose', my old Eventide 24 and 'Fiddlers Green' my new Eventide 26. On both occasions the hull was suspended above the ballast keel by jacking up the boat from underneath it's bilge plates and using supports fore and aft.
Note, use strong blocks, not bricks and use battens to hold these blocks in place, i.e. nailed across.

MORE SIMPLE ANSWERS
(1) Check the mast rake. With the boat at rest on its mooring, in normal trim the mast could have as much as 18" rake on the E24. (It was on 'Bluenose', before I altered it.) She looked a bit like an Arab Dhow! Try shortening the forestay and lengthen the back stay and shrouds as necessary. This should take out most, if not all the rake there is in your mast. We are looking for a vertical mast or at most a few inches of rake. This has the effect of moving the centre of effort of the sail forward. (Make sure the boom still clears the back stays).

(2) Try reefing the mainsail.

(3) Try using a larger foresail.

All the above involve simple, non structural alterations. Still no luck? Better but not perfect?

MODIFICATIONS ON DECK.

Fit a bowsprit. I know you don't want one, the marina will charge you more and you don't want holes in the deck etc. Well try lashing a spinnaker pole or similar, along side deck forward, so the end of the pole is about 3 or 4 feet in front of the bow, set a sail flying on it, feel the difference.


We have suddenly shifted the centre of effort about a foot further forward, so scratch your head, find a suitable plank and fit a bobstay chain or rod from the end, down to the bow, so a hole or two will have to be made through the stem, but this is a good way to combat weatherhelm.

Don't want a bowsprit?


Then there are alternatives. Reduce the main sail by cutting 1 or 2 foot of the foot. (a job for the sail maker). This has the same effect as reefing the sail, but by doing it this way we keep a better shape sail and this maintains our sailing efficiency. While on the mainsails, make sure yours has not gone baggy, it should have a shape similar to an aircraft wing.  Baggy sails give you weatherhelm before you start!


If due to old age or cut, yours is fuller aft, your boat will heel more than others. Heeling increases weatherhelm

HEELING is another reason for excessive weatherhelm. As the boats under water shape changes by heeling, the boat tries to turn on its own. So flatter cut sails will also help.  Ballast weight comes in here again of course.

The Eventide 24/26 should sail at around 15 degrees of heel and carry full main and genoa in a force four wind. Look over the side you should see about 6" of hull still clear of the water, if not try adding weight along the Centre line of the boat, lead blocks, painted iron pigs or gravel or sand in strong Poly bags. Then take her for another spin, I think you will be pleasantly surprised, if this works, fix it all in position until refit time.  When we have tried all the above and we will have had some success, we now have to decide, do we live with it as it is or do we continue, if we decide to go further we must take the boat out of the water and be prepared to do some work.

After hauling out, once ashore, check the weight of your ballast keel, is it the recommended weight for the boat?? An up to date Eventide 24 should have 1020lbs+. The Eventide 26 1660 lbs +, Waterwitch 3300 lbs +.  these are minimum weights!!!

You don't know the weight of your keel?

Ballast keels.  The best way is to measure the depth of the cast iron....  If you cannot see it for sheathing, use a magnet!

The later Eventide 26  keel was 9 or 10 inches deep. About 10 ft long....  the early one 7 inches....  If you have extra weight on the inside faces of the bilge keels, that will help, but you really do need  1660lb as a minimum.  I advise owners to build to 2000lb as a target.  The reason for that is the extra gear we tend to carry these days!  Plus many of our boats are rather overbuilt..... and under ballasted!

 

If you have an early boat, pre 1973, with lighter ballast and you added ballast on the inside, and it  of course worked, now is the time to look at the question of weight and add that weight to the ballast keel. This puts the weight in the best position, on the bottom and also it deepens the keel by about 3", which will also give the boat a better bite in the water, as per the later editions of the plans.

A 3 to 4 inch deep, steel box filled with steel and cast iron and bonded with cement will weigh somewhere around 300-400 lb. A cast lead section to bolt on to your existing lead keel of the same dimensions will weigh about 500-600 lb.  Flat sheet of steel plate 1" thick, in a sandwich might be an easier solution....

Now the trick is to fit the box that you have made between the hull of the boat and your existing ballast keel, don't be put off, it is not as difficult as one might think. This method has been used on 'Bluenose', my old Eventide 24 and 'Fiddler's Green' my new Eventide 26. On both occasions the hull was suspended above the ballast keel by jacking up the boat from underneath it's bilge plates and using supports fore and aft. Note, use strong wooden blocks, not bricks and use battens to hold these blocks in place, i.e. nailed across.

Once the keel has been deepened, it might be prudent to add a few inches to the bilge keels too.  They should really be only about 2" shallower than the main keel, so when grounding that takes the weight first. Either you can temporarily bolt on extensions, or you can remove the bilge plates and have them welded, or replaced if corroded, galvanised and refitted with new galvanised bolts.  They will be fine for another 20 years or more!  Don't forget to fit anodes though! 

If you are simply pulling a main keel bolt, which for peace of mind as well as to comply with insurance surveys, it may well be worth doing the extra ballast trick, the steel slab addition as in the 'Owners Tips' page or the  box filled with cast iron.       If the old keel is glassed over, you might have to cut the glass along the joint, you can easily epoxy it over later....   You will have to have new galvanised mild steel bolts made up, but they are easy enough to make and the peace of mind it will give is great!

FILL IN THE AREA BETWEEN KEEL AND SKEG

WEATHERHELM is not only helped by the addition of the weight and the additional draft, i.e. the 3" or 4" we have talked about in the previous paragraphs, but great improvements have earlier been made by moving the sail area forward in relation to the keel area. If we fill the space in  between the ballast keel and the rudder we will have made the keel longer and therefore its centre of effort will have been moved further aft. Resulting in a very noticeable effect on the weatherhelm.

There are two ways of doing this depending on the construction of your boat. This is a modification that has been used to great effect on many boats. The first, if your skeg is steel, then it is quite simple to make up a template in cardboard and have a piece of sheet steel cut to fit, about 3/8" thick. This then will have to be through bolted to the keelson, sealed with Sikaflex or similar.  Remember that this will add weight  and cause some imbalance trim, which you will have to compensate for, by trimming the forward end of your vessel with a little internal ballast.  The boat should always sit nose down slightly when afloat empty on the mooring, our weight will bring the stern down when we are sailing!

Filling in the space between the keel and the skeg is a pretty easy task.   Many owners have done it without drilling up through the bottom of the boat at all! 

Another way is to use a sheet of good quality ply.  Make a template from cardboard then cut the ply to fit the gap.  Fit two timbers approx 2x2 to the bottom of the boat the correct distance apart so the ply is a tight fit between them.  Fasten every 6" with bronze screws.  You can drive bronze screws through the two timbers and the ply every 6" to secure the top.   The timbers should be streamlined at the ends to fit onto the rear of the main keel without an abrupt disturbance to the water flow.   The ply should be epoxy coated after a dry fit, to ensure it lasts. On the rear of the wooden part of the keel, steel, (later galvanised,)  rectangular straps or plates are fastened, shaped to the deadwood and the ply, they are then bolted with mild steel, galvanised bolts  or screwed with mild steel screws, galvanised, to the timber.  Lower down the same can be done, through bolting the ply and the forward ends of the straps closely gripping the cast iron of the keel. 

The rear end of the plate is fastened to the skeg the same way.  Try to fair off all the fittings and bolt threads etc.  This is not a difficult task and could be done in a couple of weekends.  Use good mastic, Sikaflex or similar to bed it all down.

(Do not use Stainless Steel, of any quality, as a fastener under water.......)

Another way of doing this, if your skeg is wooden, is to laminate a filler made from 1" thick layers, epoxied (glued) and screwed up to the hull, faired off either end, the effect is the same but without the additional weight.
 

I am no professional boat builder,  although I built my boat!  Just a normal DIY'er, all these things are possible with a little advice...  Epoxy and modern sealants helps too!  Many light engineering firms will allow their junior lads to make a set of infill keel plates up, or bolts etc, mostly from scrap for pocket money....  Even if you had to pay full price, mild steel is cheap. Find your local galvaniser in Yellow pages, then get all you can  together in one go for them....  Cheap!  Talk to them first about what you want to coat though, as some fittings, pulpits etc, have to have little holes drilled in discrete places to allow them to coat without trapping air.....  and exploding!  Galvanising lasts for years on deck, unpainted, and below the water, with a good etch primer, the same....  my skeg to rudder fittings are still like new, 28 years on.... Galvanised, primed and painted with epoxy....

 

Do not mix your metals, (steel with steel and bronze with lead). Note, it is not advisable to use stainless steel for any underwater fittings or fixings, as stainless only keeps its good qualities, when in contact with air.

 

TRANSOM HUNG RUDDER.
You already have a bowsprit and a long keel?? One or two possibilities are left, one is to move the mast forward. This, I think, is over the top, the second is to use a transom hung rudder, which is part of the boats under water area, and if moved aft, has a similar effect on weatherhelm, making the long keel we talked about earlier, even longer, therefore enhancing the effect. The keel length for this purpose can be measured from its forward point back to the end of the rudder. As you will see we have yet again moved the centre of lateral resistance aft. 

As a by product of the transom hung rudder idea, you can also usefully extend the cockpit aft to the next beam, making more useful space and reducing the stern deck area.  You can rarely reach to the back of that locker anyway and side lockers under the seats are far easier to use!  I have done this on both the Eventides I have owned, and it works brilliantly.  Maurice has produced a nice drawing for the transom hung rudder for us, available free from us, just mail.....  Freeing the aft end of the cockpit from the tyranny of the tiller and extending the cockpit to 6 ft length, approx makes it a useful working area and lounging one too!


You may  have a long space in front of the new rudder between it and the prop...   This is alright, but under power in a sharp turn the prop thrust may miss the rudder, and you may have to resort to filling in that space, this was done on 'Bluenose', my E.24 by placing a plate cut from marine ply in the area. This was supposed to be temporary, but was still in place some 25 years later. The effect was a marked increase in manoeuvrability, plus a further reduction in weatherhelm.

Extend the skeg at the bottom, to 'support' the base of the rudder.  Did not really hold it up, but stops ropes etc getting in there....  ( the rudder actually 'hangs' on a pair of pintles on the transom)

When filling the space in front of the rudder,  watch out for the prop. Do not get the infill too close, you will get vibrations... 

On 'Bluenose' I used two 'L' shaped bits of angle iron, bolted  back to back through the bottom of the skeg and at the outboard end of the angle fixed a vertical pin to engage with a tuphnol hollow bearing fitted to the rudder heel.  I could slide a ply plate between those angle irons bolted through at it's base and at the top of the ply panel, under the hog, I fixed two hardwood battens, 1.5 inch square, with a gap to slot the ply into and cross fastened the ply in with bronze screws.  The end effect when all painted up was quite neat and has survived 25 plus years...  

The Transom hung rudder  alteration  is easy!  I have made  two of these now, the first I used a steel 3/16" plate right through the middle, but it was a bit heavy, my 'new' boat now has one with 3/16" ply as the middle section, the whole shape of the blade and stock.  The sides are beefed up with 4" x 1" Iroko, top to bottom, epoxied and screwed with bronze screws.  I then cut pairs of ply cheeks, each one smaller than the last, and built up a back to back 'aeroplane wing' shape.  First using a power planer, then sanding off with a belt sander, using the laminations as a guide, it was simple.  Epoxy coated and filled the result is a good shape and strong rudder.  Hung on fittings I had made up by a local S/S man, to fit the finished rudder, they have been in use 26 years no problem. 

I have written two articles on the hints and Tips pages, expanding on this..   (there are quite a few pics on the Featured boat page too. )   Well worth the effort, makes the boat handle better and in the case of the transom hung rudder, by expanding the cockpit and removing that tiller from it, transformed the comfort!  I really liked making a fancy tiller as well, not as difficult as you might think!


EXTEND THE AFT EDGES OF THE BILGE KEELS.
Not often tried, but it does work. This will normally involve the removal of the bilge keels and a trip to the local engineers, and then a trip to the galvanisers. The amount you add is optional, some have only made the aft edge vertical, others have raked the aft edges to match the forward edge, but beware if you drop back at any time onto an obstruction, you may hook onto it, or a line or chain. It is unlikely, but the chance is there.

Some owners have actually removed the bilge keels and moved them a foot or so aft, that also works, but you have to adjust the angle of the lower edge of the keels, as they will be now tending to cock up at the back slightly as you have moved them back along the underwater curve of the hull. Remember to plug the old holes!

Make sure your bilge keels extend about 1 & 1/2" to 2" less than your main keel, this will ensure that you sit on the main keel first  but don't topple too far over when drying out on the hard either.

 

All of the above just shows there is more than one way of sorting Weatherhelm!

 

It is not suggested you should do all the things that have been mentioned at once, you may find that just adopting one idea will be sufficient for your particular boat, but I hope most of the options have been mentioned here. Once you are sailing, sail trim is very important. A sail over sheeted will produce weatherhelm by causing the boat to heel to much, thus changing its underwater shape. Yachting Monthly produce a very good booklet by Bunty King, entitled, 'Sail Power' a few pounds well spent will bring you a mass of information, from mast rake, to the setting of spinnakers. The pleasure one can get from watching the antics of the crews aboard modern Tupperware boats, as your 'old wooden tub', passes them by.!!

John Williams.


 

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