Skeg .... or not!

[Waggles]

Hi all,
I own an old Invader 22 yacht which was damaged in the recent storms, it is kept on a drying mooring and the sideways wind pressure as the boat began to float cause the entire skeg to break off together with all the underwater part of the rudder, all parts lost. For those unfamiliar with the boat the skeg was approximately the same depth as the twin keels and ran the full depth of the rudder, indeed the bottom rudder pivot was mounted at the base of the skeg with two more on the transom.

I know of one other Invader that has had the same problem and another exhibiting cracks so it appears a design weakness for drying moorings.

I have seen Invaders that do not have said skeg and look as though they may never have had. Due to the hassle I am tempted to forget the skeg altogether, beef up the two remaining rudder mounts and fashion a new rudder ( possibly lift up to avoid damage? )

My question is what will I lose ( apart from weight! ) without the skeg? I imagine the boat will be a little less stable in yaw but more manouverable? Any comments?

 

[jason -and the arguenauts]

You will lose some strength which you will have to make up in the top bearings and in the shaft. You will gain the ability to balance the rudder so the boat is lighter on the helm, and the potential to improve manoeuverability. You will have more risk of rudder fouling.

 

[Waggles]

Thanks, sounds like a plan to proceed with then.

I had thought of rudder fouling and damage by striking something hence my thought to use a steel raising rudder plate though admittedly a rudder plate would lack the preferred 'aerofoil' shape.

 

[michael_w]

Will the skegless rudder take the weight of the boat as she dries out?

 

[alahol2]

Depending on your transom, you could consider a vertically lifting rudder. This can then be made from laminate or hardwood and fashioned into a full aerofoil section.

 

[bedouin]

As others have suggested - surely a skeg mounted rudder is stronger than one without - so if the forces when drying out are such as to break off the skeg then an unsupported rudder doesn't stand much chance

 

[ianat182]

Skeg or not....

ALAHOL- You beat me to it- lifting daggerboard type has the advantage that even partly raised you still have steerage way in shallows and it doesn't touch the bottom;however, as the OP states the skeg was the original setup,and that it goes the full depth of the rudder. It may be that it was intended to be a third balance/support point when taking the ground. Clearly this would not be possible with the daggerboard type.
If regularly drying out then perhaps a pair of legs astern could be fitted,making the d/b an option.
A thorough check of the structure in the skeg area is now obviously needed ,out of the water.


ianat182

 

[Waggles]

Thanks for your thoughts so far.

Will assess structure when she is recovered but at present she is still afloat ( no leaks ) As I understand the skeg was a separate moulding passed through a opening in hull and then glassed in place so all should be well structurally.

She takes the ground quite happily on just her twin keels ( which are reasonably long ) and seems to show no signs of tipping back so I think there would be little weight if any on the rudder were it to touch. I was planning to make the new rudder shorter ( but broader and balanced ) I was thinking along the lines of a form of 'kick up' rudder held down in place with a shear pin that would break if any real weight came on it to prevent transom damage whether the weight were caused by hitting something or bad luck when drying out over a rock or something.

Obviously the rudder was stronger with the skeg so I will need to junk the existing pintles / gudgeons for stronger fittings, any ideas where I can find such things or do I go down the custom manufacture in galvanised steel or whatever? All I can find on the net so far are dinghy / day boat sized stuff

 

[Wansworth]

Came across two boats that had the original skeg mounted rudder converted to transome hung with improved performance.Mac 26/westerly nomad