how to locate waterline?

[JeffM]

Finally painted the hull, and ready to tape off the waterline for a nice deep red stripe. How do I do this? Waterline is measured on the plans, but not sure: (1) how to get it straight and level along the entire lenth, (2) exactly where to locate it, and (3) how to make it look nice, given the cs20's hard chine with the actual waterline almost entirely below the chine. My best guess at getting it straight and level involves a water level made of a long piece of transparent tubing. How did you all deal with these issues?

[Ken_Potts]

I haven't dealt with these issues but I think it might be possible to rent a laser level. Level the boat up and get a laser level that scans to show a horizontal line.

[PAR]

Ray's right, I too use lasers a fair amount.

Level the boat both fore and aft and side to side. This will take some time, with jacks, shims, etc. Use the waterline reference at the bow and stern to level her fore and aft and a thwart or the transom corners using a bubble level, for the side to side. When your laser hits the bow and stern reference locations and she's level athwartship, then you ready to mark off the line. Scribe it in, so you don't have to do this again, you'll be able to see the scratched in line under layers of paint or after light sanding during repairs or a repaint.

I use the fancy rotating surveyor's level on waterlines, but you can do a fair enough job with a pin point on a tripod, that gets moved along as you work. You can rent a remote controlled, self leveling, pin point or revolving laser, which is very handy for marking it solo.

[JeffM]

Thanks! Paul's method of scribing it in is also worth its weight. I do in fact have a cheap rotating laser thingy that I bought (impulse purchase) early in the building process, but then never had urgent need of. I guess I wasn't sure I trusted the thing's bullseye bubble level to get it truly level over a variable projection distance. But I can check it at a few reference points. Now I'll finally justify its purchase.

Any thoughts on my other issues? I'd like the line to look fairly uniform at different viewing angles. Should I keep it above the amidship chine?

[PAR]

I tried those lens style of lasers Ray and didn't like the thickness, but more importantly the way the lens "clicked" from vertical to horizontal. I was able to click it into horizontal and it wasn't the same place as the previous setting. I may not have had it clicked fully home and it wasn't an expensive laser, but this turned me off, so I got the other one.

Jeff, your waterline should have some sweep to it, unless viewed from water level. This is a function of the straight line on curved surfaces, which is also at various distances from your eye, all conspiring to trick your eye. When you do a waterline with a laser, then see an eyeball job or water level efforts, you'll notice the difference. Yours will look machine straight and theirs will have slight humps and hollows along its length. The first time I used it was on a lapstrake hull, which is difficult to get right with the best equipment and highest level of skill. You'll never go back, nor do a straighter line.

Don't be surprised if leveling the boat takes a fair part of an afternoon.

[Howard]

This may warrant a separate thread, but can you guys post pictures or specific makes and models of the lasers you are talking about? How they work and what features you need.

Just about everplace that sells hardware (including Walmart) sells a selection of laser devices, intended for everything from hanging pictures to building a house.

Waterlines aside, I've often thought that one of these tools would be a great way to mark centerlines, and to level cleats and just about everything else on a boat, where there isn't a square corner anywhere to measure from.

[JeffM]

Okay, now I know all I need to to do the waterline, except...where it's supposed to be! I know I saw it in the plans long ago, but now I can't find it. (I'm also missing one page--of course it's probably the one I need.) Can anyone help out?

[JeffM]

Yup, that's the sheet I lost. Thanks for hunting that down for me, Ray!

[JeffM]

Howard, here's one NOT to buy: Strait Line laser level 30 (my impulse purchase). After taking the time and trouble to get the thing's spirit levels level, and getting the height right, I twisted it 90 degrees on its bearing and watched the levels go off again. (After this happened a few times, I went back to a pvc tubing water level and my eyeball. Looks pretty good.) It figures the level'd be a dud--guys can't even spell. Or maybe they're being diabolically clever: its sure I was in tough straits trying to use it!

[Howard]

Do a Google search for "laser level" and Strait Line comes up often.

What I had in mind was something like this:

http://www.mytoolstore.com/robolasr/robo2.html

But for about 1/4 that price. :roll:

Seems to me that a product like this that would self level and with the ability to project vertical and horizontal lines would be a BIG help when installing seats, partial bulkheads, etc. (as long as the boat itself is also level in both planes).

But lacking that, a bucket of water filled to the level you want with a clear hose to measure with is low cost, and last time I checked, gravity is still working!