Waterlines

[doug748]

I am thinking of having some topside work done. Has anyone any tips for measuring and recording the waterline before it is obliterated? Thanks.

 

[fisherman]

GRP? Guessing so. Measure down on bow and stern before obliterating. Some sort of jig/fixed point and a laser line. Lot easier than how I did mine, by a string across away from the transom, then by eye set one across the bow in the same plane. Then a fore/aft string either side between the other two strings. (all these strings were tacked to props on neighbouring boats). Now you can project the line along each side by eye, line the strings up, get someone to apply dabs of tape while you direct.

 

[fisherman]

Course, I suppose you could put dabs of tape along the top rail with a measurement written on each?

 

[sogood]

Alongside the above, some " before" photographs wouldn't go astray. Just a belt and braces approach.

 

[rogerthebodger]

I am thinking of having some topside work done. Has anyone any tips for measuring and recording the waterline before it is obliterated? Thanks.

I measured down from the deck at each stanchion bow and stern ends and centre and noted each measurements on each side.

 

[johnalison]

If you are feeling bold you could score a fine line at the margin. My current boat was marked from new a bit like this.

 

[fisherman]

If you are feeling bold you could score a fine line at the margin. My current boat was marked from new a bit like this.

perhaps a dremel would do that. If you mark or measure three stations a laser would do the rest, whether boat is level or not.

 

[JimC]

... If you mark or measure three stations a laser would do the rest, whether boat is level or not.

I'd be glad if you could explain just how this is done as I have a task similar to the OP's facing me.

 

[Daydream believer]

Get some of the brown packaging tape 50mm wide. Put lots of short pieces ( 6 inches) with bottom edge along the water line ( some will come off that is why you do short bits as one long one might come off) These will all give you a line 50mm clear of the waterline ( on the angle it will not be above the water but along the hull)
Then run a single strip along the top of these pieces which will now be parallel to the waterline but clear of the water by 50mm. That will last a day or two whilst you are waiting for the boat to come out.
When it comes out put the short pieces that washed off back to establish the true waterline again using the long strip as a guide.
Then put some below this waterline repeating the process so you now have a line of tape50mm below the waterline where any topside paint will not touch it. You could use duct tape for the final tape if it has to be there for a while. Will take a bit of effort to clean off but will do it when antifoulling. But you always know that you are the width of a piece of packing tape clear of the main tape from the waterline

 

[fisherman]

I'd be glad if you could explain just how this is done as I have a task similar to the OP's facing me.

faced with a blank hull, if you have three places where the w/l can be marked, set up the laser one side and basically move it about until it is hitting all three marks, everywhere between marks is now correct. It will throw a thin red line on the hull.

 

[JimC]

faced with a blank hull, if you have three places where the w/l can be marked, set up the laser one side and basically move it about until it is hitting all three marks, everywhere between marks is now correct. It will throw a thin red line on the hull.

OK got that, thanks.

 

[doug748]

Thanks all.
I will mark at 1ft intervals and measure, also photograph and have a look with a laser before the work to see if I can grasp it.