Curved Tape Line?

[model 10]

How do you pull a curved tape line on the hull? The bottom stripe on my boat is the waterline but the upper side of that stripe is curved. Not the sheer line but another curve. I have tried several times to tape this line but I get lost as the hull curves out of sight.

[Orion Jim]

Pictures?

[four winds]

In a past life I have striped a dozen dozen cars. And more recently a few boats. Boats are more difficult for several reasons of which one you mentioned.

Not sure I can help much as I could do it much easier than I can describe it.

Most likely you are securing one end of the tape, then stretching out a few feet of tape and holding it close but above the surface as you "sight" down the tape. Then slowly moving the tape closer as it begins to lightly touch the surface beginning at the secured end and moving towards your position. Never actually touching the tape to press it down until the end.

Then before it contacts all the way to your position, stretching out more feet and repeating. Never working right on top of the contact point is important. As is not pressing it down as you go. It can be lifted and adjusted this way. And press down firmly at the end.

Here's an idea for a curve. The long tail of tape is a tangent of the curve being created. The tail is a tangent from the point of conact on the surface. From a distance this can be visualized. For a mostly horizontal surface as you slowly move the tape closer your hand motion slowly moves up or down. Slow and smooth, eyes on the contact point.

Also, I often place small marks of tape or pencil along the curved path above or below as appropriate, maybe a foot or two apart. Then my eye shifts back and forth from the contact point to my target marks. As I move the tape slowly and smoothly, very important. Sometimes I get it on the first try, sometimes not. Not pressing as I go makes it easy to lift and adjust. But it is important to never pull hard enough to stretch the tape if it's vinyl.

Google "placing stripes on car or boat youtube" for help maybe.

http://m.youtube.com/watch?v=XtTpADj5WCU

My data is throttled for seven more days so can't watch vids to offer good links.

[model 10]

Well thanks for the info. First off, it seems I have been starting from the wrong end of the boat. I have only painted aircraft and you start from the front. I will try it from the rear next time.

[steamgoat]

You have a good waterline but you want to find a 'top line' to create a bootstripe ? If you have a good waterline and you want a ,say 3'',bootstripe.Get a small level and tape some wood to it so it is 3'' top to bottom. Hold it with a pencil laying on the top and one on the bottom. Put the bottom pencil point on the waterline and make a mark 3'' above with the other pencil. Keep doing this all around the waterline,keeping the level horizontal and moving the pencils in/out to mark. A bit tricky to explain but this will give you a line parallel to the waterline regardless of the curve of the hull.
Of course,you have to have a good waterline to start with.

[model 10]

Originally Posted by steamgoat

You have a good waterline but you want to find a 'top line' to create a bootstripe ? If you have a good waterline and you want a ,say 3'',bootstripe.Get a small level and tape some wood to it so it is 3'' top to bottom. Hold it with a pencil laying on the top and one on the bottom. Put the bottom pencil point on the waterline and make a mark 3'' above with the other pencil. Keep doing this all around the waterline,keeping the level horizontal and moving the pencils in/out to mark. A bit tricky to explain but this will give you a line parallel to the waterline regardless of the curve of the hull.
Of course,you have to have a good waterline to start with.

But you see the bottom is straight but upper edge is not. It has a curve somewhat like the sheer line. Very swoopy.

[HopCar]

Guy, does the curve you are trying to strike actually follow the shear? Could you measure down from the shear to get a set of points to connect?

[model 10]

Originally Posted by HopCar

Guy, does the curve you are trying to strike actually follow the shear? Could you measure down from the shear to get a set of points to connect?

I wish but it's different.

[roverhi]

A carpenters transit level will do the job. They used to be common but have largely been replaced by lazers which will also work. Set up the transit/lazer and traverse it along the water line/boot top and have someone make marks on the hull and connect the marks with masking tape. Because the hull is not vertical all the way around, a line that is a constant width will appear to taper in at the bow and stern where the angle is steepest. The water line in those areas needs to widened with progressively more width as the angie decreases from vertical.