Laser pointer line-up

[Jonas]

As I'm building the bulkheads for my 21' Penguin, I'm thinking about the best ways to line them up on the building jig. I'm thinking of drilling small holes in the bulkheads a given distance from the CL and WL, and shining a laser pointer through to check alignment. Has anyone tried this?

[whb]

no, but if you calculate exactly the "right" spot where the whole should be on each bulkhead I think it would be a heck of an idea. Your bulkheads would have to be perfectly vertical in order for this to work.

Good luck

Howard

[whb]

sorry about the spelling. Or maybe it was a freudian slip. Whole or hole in this case either works.

[Eb]

Jonas,

Never tried it, but it seems like a good plan.

Might be easier if you mark a 3" or 4" horizontal and vertical X at the measured spot on the bulkheads then drill a 1" hole at the center. That way any drift from drilling the hole wouldn't matter. By holding a straight edge to the grid lines you could see how much up/down right/left you need to shift your bulkhead to get them spot on.

If you do try it, I'd like to know how well it worked.

Eb

[RGM]

Lasers are certainly alot of fun, but stringing some properly tensioned piano wire thru holes and targets as previously described by Eb works better. You can accurately measure off of a wire, not so with a laser beam. You can place a straight edge or end of a measuring device against a tensioned piano wire. It's hard to do against a laser, they are very soft. Of course, how accurate do you really need to be? Good luck.

[casem]

I did that with the jig for my Whilly boat (15' and 7 station molds). It worked great. I think I made my holes 13/64", 3 holes at each station, and I was just barely able to get the laser to shine all the way through all the holes. I had trouble with string lines because they sag and you never know if its barely touching one of the holes, but it sounds like piano wire would work better.

[Dave Fleming]

Piano wire, turnbuckles and two stout verticals are the method of choice in most yards.
Amazing how taut a line can be drawn with this method. Once done it is no problem to horn the moulds.

[DougWilde]

I depends upon whether you are working alone or will have assistance.

If you will have the luxury of a second pair of hands, forget the laser and piano wire. Drill the holes as you suggest and install and align your forward most and after most bulkheads. Put ANY bright light source behind one of the holes. Install an intermediate bulkhead and sight through the other bulkhead's hole, looking for the light source. If you can see the light, they are aligned. With the laser you'll have to fiddledick some way of pointing it accurately, something that won't easily be disturbed.

KISS

Doug Wilde

[wolfietuk]

lasers are fantastic if you have the right steup. They can eliminate one set of hands and are very true. for what you are doing a rotary laser with a jig to hold it above the boat would be great. It will only cost you a couple of hundred dollars. and take five oto eight hours to set up a proper jig.

Please note ny sarcasm is not ment in a mean way. I use lasers professionally and love them. but the cheeper ones, without proper set up are time consuming toys.

Rick

[Dave R]

My father used that idea with an inexpensive laser level. After he made sure it was level he drilled a hole in the first board at the spot where the laser hit. Then he moved on to the next board and drilled another hole. This worked quite well. Of course he was building a long raised bed planter in his sloping back yard. It did allow him to get a level line to work from.

[Jonas]

Thanks for your helpful replies. Dave's suggestion of piano wire, turnbuckles and stout vertical supports at either end sound like a good and simple solution for my situation. A high tech solution sounded like fun, but there's nothing like the tried, tested and true, and simple. Cheers!

[David Tabor (sailordave)]

When I built my canoe I drilled small holes in the forms at the same height from the reference line and strung monofiliant (sp) fishing line through. When the line ran through all holes w/o touching I was reasonably certain the molds were straight. I also blocked the line of the strongback at each end and measured to see if the strongback had any distortion (it did, but just a hair) and that should correspond to the amount you have to adjust each mold.

As far as lasers go, I've used them in construction, but there you're talking about a 1/4" dot;great accuracy for a gymnasium ceiling or other big project; way not accurate for small boat building. This kind of laser was great in that it rotated and you could line up things to the beam; could do that with a reference lin on the molds but piano wire is going to be a hell of a lot more accurate and easier. David

[Dave Fleming]

I recall trying laser transit on the jigs for 250 foot tuna seiners down here at Campbell Shipyard in San Diego. With all the movement about the yard we soon reverted to water levels for setting up. No trouble lining up within 1/8 th of an inch over 100 feet or more with one of those. And you didn't have to worry if some 'blankety blank' forklift driver had set 5 tons of steel plate right over one of the monuments either!