Im sanding my boat down, how do I mark the waterline?

[Perithead]

I am in the process of finishing sanding my Southcoast 22 project boat today(I know some of you must think, does he just sit at home all the time? No, we are having some of our house painted so I must house sit, lucky me.)

I will be sanding both under and above the waterline down tot he gelcoat. How is some way that I can keep my waterline marked though this whole process or painting above and below it? I do want a blue stripe lengthwise down the hull at the waterline to mark it, but I will be painting the bottom and top the same whitish color.

I am thinking, go ahead and get my strip in place and just tape over it?

If I do, do I need to paint a blue strip? Or should I go with some sort of vynil* sticker simular to the pin stripes that were on the boat that help up for 33 years?

[Giulietta]

Normally you tape the existent water line, sand and finish above, then redo the water line tape, sand anf finish the bottom.

Another option is to measure from the deck to the existing water line, in increments of 2 feet or so, all along the boat...then once you have finished the sanding and have repainted the boat..remark those measurements with a pencil..and you have the new line

I use vynil sticker for water lines..haven't painted the water line for decades...

The strips are clean, and you can change clolour every year..I do...first year blue and blue..last year Green and blue..this year red and blue...I have 2 lines of different widths..looks better..I think

[mikehoyt]

Perit

Be careful what paint you apply below the waterline. 2 part paints are not for use below the waterline and some paits do not like anti fouling applied over. I refinished rudder on my last boat using a one part pant (Brightsides) and then painted over the bottom one inch or so with my antifouling paint at the waterline. The Brightsides did not like this at all.

Mike

[jrd22]

What Giu suggested is what I have seen in the yards, measure from the deck down to the waterline. I would mark it more frequently where there are curves so it will be easier to draw a good line. The ones I have seen measure very accurately, within 1/16th inch and mark with tape on deck where they measured from.

good luck on the project, John

[sailingfool]

MY advice is to paint the waterline, and if possible duplicate the existing lines. The problem with using tape is that the tape width is constant - as a boottoop bends on the curves of the topsides the apparent width of the line, as seen by an observer on the the horizontal, will vary. The boottop looks narrower in the bow and very narrow as it turns under the stern. The boottop ends up looking wrong, period.

Builders allow for this fact by varying the width of the boottop, wider at the bow and much wider, say three times as wide, tucking under the stern. It is very hard to eye-ball the appropriate witdh, you should use whatever the builder did, if you can. If the builder didn't make a properly tapered boottop, well, what can I say...

[Perithead]

Thanks guys, the measing down on 2ft increments sounds pretty good to me.

Thanks Giu.

[camaraderie]

Another trick is to use the travel lift slip...put talcum powder in the water and drop the boat in and then take it out...voila...your actual waterline is marked.
The other methods above are easier...just a little trick for boats whose waterline has been lost.

[retclt]

If you somehow lose the waterline you can rent a Rotational Laser Level. If you know where it meets the bow and stern the laser level is great for re-taping a perfect line.

[Perithead]

Im taking a short break from sanding and I think the easiest way for me may be to go ahead and put the waterline stripe on. My bottom is already down to the gelcoat pretty much with a well defined waterline. I think what I may do I get a strip of vynil and go ahead and put it on just below the water line and put some tape over it and be done with it.

This is a trailerable sailboat so it will not be sitting in a slip while I own it and probably not fro the next owner. Will the vynil stay on under the water?

Thats my only real concern...

[Giulietta]

yes it does....