How to check if the skeg is "true"

[Wideocean7]

Hi All. The full skeg on my aluminium yacht is slightly wobbly and can be moved to one side about 1". The causes are cracked welds in the frame above, which will be rewelded when I lift her out of the water (I think she took a big hit on the skeg when she grounded in a cyclone a few years ago and that's what cracked the welds). Does anyone have any clever ideas how to ensure the skeg is "true" whilst she's rewelded? I thought about fastening a line to the centre of the bottom of the skeg and running equal lengths of that line to the hull chine (assuming those are in the same position!). Or am I making things too difficult and just eye-ball it?

Any thoughts?

Cheers

[tkeithlu]

You can get it stunningly close by Mark I eyeball. One degree looks big. But, if I were unsure about it, I think I would run a 2x4 down both sides, clamped with a bolt in front and behind, and use the extension of the 2x4s to keep it straight. Sighting from the bow under the keel might also give you a good line. Sighting from well aft might also. I don't think that you will have a problem when the time comes. Sorry about the ding.

[Wideocean7]

Thanks tkeithlu. Good suggestion about the timber. I think I’ll rely on my eyeball! Cheers

[Manateeman]

You might tac weld some long pieces of aluminum rather than wood but the green frog suggestion is correct. I’ve tac welded aluminum carpenters squares and used non stretch fishing line. Eyeballing with contrasting paint gets you very close.
You can fabricate 90 degree triangles and use a laser but the carpenter squares are cheap. Long pieces of rectangular aluminum run very straight, don’t sag and can be used for all sorts of projects. 1 x 1 inch square tube reinforced with flat plate at 45 degrees is how I make my solar panel support frame. Less expensive than rectangular... just use two and you’ll have very versatile material for another project. Try a scrap yard with cash in hand.
Happy trails to you.
The manatee crew.

[Wideocean7]

Thanks Manateeman. I must have missed your reply so apologies for the delay. I'll take your ideas on board - they seem to have many uses.