Tool question, rebuilding interior.

[Hampus]

When it comes to tools, my vocabulary is not the best but I'll try to explain best I can

I've had this boat for 4 years and lived aboard it for 2. Now I've figured out what parts of it I'd like to change. I'l get to it this winter. Biggest job is to remove part of the storage under the cockpit and build a largish berth instead. How do I saw a boarg to fit nicely along the inside of the hull? The question is really if there is a tool for measuring the curvature of the hull? It's not just trial and error is it?

I'm fairly handy, but new to "boat building".

/Hampus

[Duke 48]

Hampus, There are several methods to measure for and layout a pattern. One method is to place a piece of cardboard perpendicular to the to the area to be measured then use a drawing compass - opened to a right angle - to trace the outline of the hull. Assuming you are making a pattern for a piece to be mounted vertically, with the cardboard held in the position of the "new" board place the point of the compass on the hull and the marking end on The cardboard. Holding the compass as level as possible, trace the outline of the hull onto the cardboard. You can then trim off the excess cardboard and you will have a pattern that fits your hull. If the gap between the edge of the cardboard and hull is too wide to bridge with the drawing compass it will be necessary to ruff-cut that edge of the cardboard to close the gap.

I would recommend making a full mock up of the piece to be installed before actually cutting the new board.

Hope this helps, Duke

[Hampus]

Thanks a lot!

[Ziggy]

You can use a woodworker's compass to scribe a matching line on a board. Place the piece you want to it against the hull, and use the compass with one leg tracing the curvature of the hull and the other leg (with the pencil) tracing the parallel line onto your board. You can also get a special tool like the "Perfect-butt" (Perfect Butt Profile Scriber from M.POWER Tools) to accomplish the same thing.

[James S]

Depending on how complicated the shape is...there is something called a "joggle stick" that can be an incredible aid.
Check out the below link.
joggle stick

[Oceansandmts]

Joggle stick beats a compass or profiler hands down for ease of use and accuracy IMHO.

[captjcook]

I guess I have always called it a tick stick...anyway the fastest way to make a pattern is with doorskin (thin plywood) strips and a hot glue gun. A picture is worth a thousand words!

[Bloodhound]

When you use the joggle stick to lay out the curve you will end up with a set of "points" on the material to be cut. You can then join the points with a smooth continuous line by using a spline (a long thin piece of readily bendable wood). Drive a fine finishing nail vertically far enough into each marked "point" to hold it in place and bend the spline to rest against each nail, then draw your line. This will give you the fairest line along which to make your cut.

[captintommy]

I always use foam backed poster board from the hobby store to make a full size mock-up.

[Hampus]

All excellent tips! Thank you!

[Zach]

Also... Be aware that the curvature of the hull happens above and below the line you are measuring. The thickness of the board, may be enough that the top does not sit flush to the hull, without relieving the underside. Easiest way to make that cut, is on a band saw with the table canted over.

Levels don't work... but bevel gauges and protractors do. If you like the level of something on the same bulkhead, you can measure what its angle is and get a small step farther than eyeballing it. Basically you have the choice of either building off an imaginary level, or using bulkheads and pre-existing stuff as a level flat surface.

I like to use a block plane to shape while mocking up, but I tend to use plywood scraps rather than cardboard as a template.

Lastly... You can try to shoot for perfection, (I know I spend way to much time trying to get things perfect...) but remember that anything under the piece of trim at the edge doesn't have to be perfect. If the board is going to have formica, or another hard laminate on it... the laminate can be cut perfect to the hull, and the board can miss by an 1/8th inch here and there.

[James S]

An 1/8th of an inch.....damn Zach, your good!!

[bhenry]

Believe in the power of the pattern!

[SkiprJohn]

Just a caution. If you place a hard bulkhead, platform or board directly against the inside of the hull you creat a hard spot in the hull. Sometimes its better to to be directly against the hull and use either a small space (1/4 to 1/4 inch) or use hard foam that will give a bit if you get bumped.
I've used both the tick stick and the cardboard cutout system as well as Captain Cook's method (not tick stick). I've gotten more accuracy from the tick stick. Sometimes on the cardboard cutout system the cardboard bends or gets limp and just doesn't seem to hold its shape well.
Kind regards,
JohnL

[SkiprJohn]

What I meant to say "best to not be directly agains the hull."