Wharram Builders and Friends

A Photo & Discussion Forum for Wharram Design Enthusiasts

I think it would be helpful to any new builders to have this information gathered together in one place.

My own mods. are

1.  3 x crossbeams  [ I section ]

2.  1 x daggerboard  [ + much deeper ]

3.  1 x cabin per hull.

4.  Twin backstays and no jumper struts on mast [ cutter ]

5.  Nacelle or pod under cockpit to carry outboard motor.

+ other small items

 

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Replies to This Discussion

Do you put the daggerboard in the original place? does it work? It seems to me that the original place of the daggerboard is much forward than in most boats.

Regards,

Dagger boards should be amidship for proper sailing balance. Another option is to have two boards in one hull. One in the normal location and one aft of the accommodation but forward of the rudder. Adjusting the boards up and down allows a wide range of sail balance and self steering ability. This was done in a Raka some years ago. The board in the other hull is eliminated.

Yes it is in the original position. And I agree this is probably not ideal. But it does work. I did have the JWD daggerboard  [ but never 2 ] and found it of little use. So do most owners I think, to judge from the letters in the old "Seapeople". I was not happy with leeway and needed a cure. Extending the board was an obvious and simple thing to try. If I was building from new I would do something different. But this is good and I would not justify doing all the work to change it now.

The boat is slow changing tack. But it always was. I leave the board down when tacking. In strong winds / waves and deep reefs tacking is unreliable despite all "sailing tricks" and I must take care to always have enough room to leeward to gybe her round if needed. Downwind the board does make the steering heavy if not lifted.

My theory or explanation goes like this ...Underway the CLR. moves forward on a foil close to the leading edge. On a boat without rocker like this only the bow provides an effective leading edge so the Ctr. of Resistance moves a long way forward anyway. So the board may not be so far out of position as it seems. But I admit this is only trying to fit a theory to my experience ie. that it does work.

Some sailors are happy with their boats even without boards perhaps it depends on what sailing you expect to do. I sailed without an engine much of the time, even this year I have used only approx. 2 gal [ 10L ] in a busy season.

Kevin - our replies seem to have "crossed in the post" so to speak. I agree that in theory it seems too far forward. But from observation it works. I have had this for several years now in all conditions. To windward and out to close reach there is just a little weather helm and I can sail with the helm lashed.

I spent 3 weeks sailing recently single-handed and without steering vane or tiller pilot.

I agree I would not do it this way if building / designing from new. In fact I am considering eliminating the board altogether and adding low aspect keels in a more conventional position. But since I have not done this yet I cannot say how good it might be.

Galway Bay what do you think of fitting lee boards, these can be fit to the outside of the hull as opposed to the inside furthermore testing can be done as to the position with some kind of “Jury Rig” before adding the permanent structure to the hull side. Where a deck pod is present the lee board can be fit between the hull and the deck pod...........

It will be interesting to hear if anyone has tried leeboards - certainly I have not !

I can see what appeals to you in the idea. They would need to be very well mounted. My objection would be from a boat-handling perspective rather than any other. Deep "V" hulls are slow in stays [ changing tack ]. With 2 boards you will have the extra task of lifting / lowering when tacking. My boat already takes full concentration on the helm and sheets to tack reliably. I cannot see a single-hander being able to carry out this extra task, ie. I feel it would result in many missed tacks.

Unlike either the Classics on the Tiki's the Pahi has no rocker. The "V" is also less deep or "softer". Not all JWD cross-sections are the same !  The combined effect is a very shallow hull even by Wharram standards.  This boat weighs 1500 kg light and draws only 0.5 m [20"]. In a "Keep It Simple" solution I would like to add a tapering skeg / keel to the bottom. Such a solution would still leave you with a draught of perhaps 0.6m [24"]. This is still a shallow draught boat !!

Another advantage I see with this is the opportunity to deepen the rudders. Presently my boat must be sailed round on the gybe ie the mainsail filling 'a lee may overpower the rudders and it may refuse to gybe until you have handed the sail across to the new side. Also running down/across large ocean swell it can be too slow to answer the rudders. So I feel deeper rudders would help.

But again I have not done this and would love feedback if anyone has.

I don't want to paint a picture of a boat that won't tack/ gybe steer etc. ! I am concerned with improvements in these areas. Again these problems largely disappear once you have crew, It is just that for single handing you need to reduce the workload on the helmsman.

Galway Bay you have a very valid point there I agree with the to much work and trouble part of lee boards, adding the keel, well I would not want anything that is not retractable under the boat as one safety feature of the boat is the ability to slip sideways in bad weather without the danger of lifting a hull, not shooting down the added keel idea but personally just to chicken to try.

The Pahi 26 design has leeboards, but not many people has fitted them. Glenn Tieman has had leeboards in his P26 and he reports in the Seapeople magazine that they didn't work well. I think you need a different shape of the hul for fitting a leeboard, perhaps something like the Amatasi.

The rudder in the Pahis seem small than in the Tikis. I remember from the Seapeople magazine that sombody has fitted larger rudders in a Pahi 26 and it was very happy with the result.

I think the shallow keel is the simplest solution. Another (more complicated) possibility is using a centerboard under the bunk.

Basically I am agreeing with Glenn, I found that the boards to plan were not worth carrying. But then I decided that before throwing them away I would try adding an extra 16" [0.4m] to one "just to see.." The extra work was so little that it seemed silly to not at least try it. I also expected to lose the balance and to have to move the board farther back. But it worked just fine.

A daggerboard in one hull only has worked fine for other designers. One example is the very fast cruiser/racer Tektron 35 by John Shuttleworth.

On a typical hull with only little resistance to drift the foils / keel may be +50% of resistance so even a small movement will have a major effect. But even this board at 3 sq ft [0.3m] is only 10% of one hull area, 5% of total - probably this is why balance has worked out OK.

Interesting to hear about the Pahi 26 with bigger rudders - I had not heard about this.

Classics and Tiki's have rockered keels which increases the draught. Increased draught means deeper rudders also. TaneNui 28 for example at 1 ton draws 2" [10%] more than Pahi 31 at 1.5 tons. Or at least it does in my design booklet !! So I think some added depth would be a good thing. I think this would be a better sailer if it drew 24" or even 27" with rudders to match. But again this is only opinion - I have not seen it done.

Thanks to Frank Olsen for posting the discussion Outboard Sled Question on the main forum. In the discussion Laurent posted this picture and I have taken the liberty of copying it here where Pahi sailors will more easily find it in the future. 

Large Hatches -

I got rid of these on re-build. Almost never used and too big to make really watertight.

Do any other owners use them ?  Are they worth the building or is it simpler / quicker to leave them off ?

Is it just where I sail perhaps, they are good in hot climates ?

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