Setting Up with a Laser

[mcdenny]

I've often thought one of those rotating laser transits would be useful aligning the molds and frames when setting up a boat. I finally got the chance to try as my partner-in-crime building Sparky II has two sons in the construction business and borrowed their laser units. They worked beautifully :).

This may be old news to some but I just hafta share...

The process:

1. Set up ladder frame as usual.
2. Stretch thin steel cable with a turnbuckle to create the centerline.
3. Square cross beams in ladder to wire. Make sure station spacing is correct and control face is clearly marked.
4. Mount a laser in front of the boat-to-be at a convenient working height for the reference waterline you will be using for setup. Align beam so the horizontal plane it creates is level athwartships and parallel to the wire.
5. Mount the second laser to create a vertical plane (90 degrees from the horizontal beam) and aligned with the wire.
6. Put reference marks on the walls so the lasers can be repositioned if they get moved. Check these marks occasionally to be sure the lasers have not been moved.
7. Starting at the transom, align each mold's reference waterline with the horizontal beam and the mold's centerline with the vertical beam.

Here's a couple of pictures. Now I'm sorry I didn't clean up the shop before the photo session.

http://im1.shutterfly.com/procserv/47b7cc38b3127cceb20586a8376a00000025100AZM2rdm3ct2 OA

The shelf for the upper unit was necessary to position it exactly over the wire. The lower unit just has to be close to the height you want the reference waterline, no fine adjustment is needed.

http://im1.shutterfly.com/procserv/47b7cc38b3127cceb20586a9b65b00000026100AZM2rdm3ct2 OA

This shows the beams on a mold. The lines are quite thick but the edges are well defined. Just remember which edge is the correct one. You can just make out the blue tape I used for the reference lines on the post and the top center of the body plan loft board on the far wall.

Photos aren't the sharpest as I had to turn off the flash and lights to get the laser beams to show.

Having setup the same boat a year ago using levels and squares I have to say this seemed much more accurate and much easier to do.

[katiedobe]

I used the aide of a laser when I was lofting panels for a stitch and glue skiff, a QE 16. I was able to lay the line as the C/L of the ply and pull the station widths off of that. No messy chalk line and I was working alone anyway so it was hard to streatch and snap.

Handy buggers.

[Chan]

There are lasers and then there are lasers. An affordable laser from the big box store is nowhere near as accurate as an expensive professional model.

[Rational Root]

I have just bought a clear plastic tube about 5 meters long (14' boat)

Add a large metal tin of water, and a little soap so that there is less of a meniscus.

You now have a water level.

1) Cost, less than €10
2) Accuracy does not deminish with distance
3) Works in bright light out doors
4) Requires no batteries

poke a hole in the tin near the bottom, and glue in the tube.

Poke another hole about 2/3 of the way up. Now you can simply add water and it will ALWAYS come to the same level in the tin.

Where ever you drag the other end of the tube, the water will always come up to the same height as the hole in the tin.

If you spill out a little water, just add some more in and you are good to go.

[gert]

I used both (cheep) laser & water when I set up for my Grey Seal.

Unless you have a $600 laser, it aint worth it; the water is way friendlier to use.

However, when I have to do my WL I'm gonna borrow the $600 unit from one of our installers;)

[jerry bark]

...Where ever you drag the other end of the tube, the water will always come up to the same height as the hole in the tin.



Unless you happen to drag the end of the tube LOWER than the hole in the tin, in which case the water will end up somewhere lower than the hole in the tin ;)

cheers
jerry

[Dan McCosh]

I bought a $20 laser-level, which projects a flat plane of laser beam optically. It doesn't have the self-leveling of the rotating units, but it's very handy where you want to set up anything involving a flat plane in three dimensions--bulkheads, waterlines, etc. A water level plus this item would do lots.

[merlinron]

actually, the inexpensive lasers will work every bit as good as a high dollar "professional" one for our purpose. the high dollar ones just hold a tighter laser line farther( 50 ft and more) and will be easier to see in brighter conditions. most cheapos aren't as bright, but will work out to about 35-50 feet..... should be more than enough for most of our size projects. if you have trouble seeing the laser line, tape a bright white piece of paper on the form where you will place a reference or benchmark, the laser line will show up on the white paper much better.

[Bob Smalser]

Bought this Berger in 1998 for around 800 bucks. Accurate within 3/32" at 80'. That may be a bit tighter than you need for a 20' boat.

http://pic20.picturetrail.com/VOL12/1104763/3297171/59962268.jpg

[Ken Hutchins]

El chepo laser, a turntable borrowed from a Victor Talking Machine a couple scraps of wood and 3 leveling screws works just fine.:D
http://im1.shutterfly.com/procserv/47b7d704b3127ccebcc267c17b0000000036101IZt2LVo4Ys

[Rational Root]

True, that's why you have a hole in the side of the tin, so you can always refill to exactly the same height.

In fact, you you bring the tube up to high, you will spill water out of the tin through the hole, so, you need to top it up a lot.

OR you can just use a line on a clear glass jar. Slightly less accurate, but less hassle. Still way more accurate than I need, and VISIBLE IN DAYLIGHT


Unless you happen to drag the end of the tube LOWER than the hole in the tin, in which case the water will end up somewhere lower than the hole in the tin ;)

cheers
jerry

[Tom Lathrop]

Cheapo or expensive, laser light travels in a straight line. I used a cheapo laser to lay out the corner heights of my boathouse floor. later borrowed a neighbor's expensive non laser transit to check it. Result was within human error. The cheap lasers will do much of what we need. Also used it to lay out waterline on a runabout. Worked fine for that too. It has since gone bonkers so I am thinking of buying a slightly upscale one though.

[Bob Smalser]

It has since gone bonkers so I am thinking of buying a slightly upscale one though.

The major advantage of an expensive, accurate laser isn't that you need accuracy measured in 32nds to build with, but repeatability over a large number of measurements, as error swings both ways.

If your standard is a 1/8" tolerance across 50' and the structure is sufficiently complex to require dozens of laser measurements, you'll achieve it much more reliably with an instrument accurate to a 16th across 50' than one accurate to an 8th.

[Flying Orca]

I used a laser on a tripod to set up the frames on my Shilling and it worked like a charm. Considered the water level, and will probably use a water level for the WL.

[Tom Lathrop]

The major advantage of an expensive, accurate laser isn't that you need accuracy measured in 32nds to build with, but repeatability over a large number of measurements, as error swings both ways.

If your standard is a 1/8" tolerance across 50' and the structure is sufficiently complex to require dozens of laser measurements, you'll achieve it much more reliably with an instrument accurate to a 16th across 50' than one accurate to an 8th.

True enough Bob, but this calls for a good quality leveling bubble or one of the expensive automatic jobs. It has little to do with the laser itself.

[gert]

It has little to do with the laser itself

Agreed, it was getting the laser shooting level in 360 degrees that was the problem, not the accuracy of the beem.

As for the water level you don't need a can at the end, just leave the tube 18" or so long on each end and plug with 1/4" rod when you move or store it.

[rbgarr]

I get the most use from a laser when working inside a (usually large) boat that's ashore when doing repairs, woodwork, etc. The boat doesn't have to be cradled level athwartships or fore and aft if a good set of reference points can be ID'd. The laser can then be useful for marking interior lines level to the waterplane when afloat.

[Ethan]

Bought this Berger in 1998 for around 800 bucks. Accurate within 3/32" at 80'. That may be a bit tighter than you need for a 20' boat.

http://pic20.picturetrail.com/VOL12/1104763/3297171/59962268.jpg

Bob, which model Berger is that? I've been looking at the Berger's for some non-boat construction projects and would be interested to hear what you've liked/disliked about yours.

Thanks, Ethan

[Bob Smalser]

http://i5.ebayimg.com/08/i/000/c7/61/bf13_1.JPG

Mine's a LM500 I've used for 10 years to install stormwater controls, bioswales and in construction. Love it for working alone, as I used to use a Dumpy level and traffic cone to hold the elevation rod. Two level bubbles, three accuracy settings, weatherproof, has an alarm when the tripod sinks out of level, good factory service after you hit it with a machine, easy on batteries and remains accurate. You can use the laser alone against a wall in a darkened room or use the receiver.

They are incredibly fast and easy compared to a water level or Dumpy level, which means you use it more and do better work. You can really get a floor flat using one of these to shim sills and joists. I'd like a larger, elevator tripod, as in construction it's handier to raise the level and use a shorter, lighter elevation rod you can carry in your pocket. I generally make them out of wood and use them as story poles for multiple elevations. The receiver also fits a framing square for finer measurements than on the elevation rod.

http://i16.ebayimg.com/01/i/000/90/11/ae86_1.JPG

If I were buying new I'd buy a self-leveler. And maybe even one that also shoots vertical. I'd be less hesitant to move the tripod with one of these.

[paladin]

I used the laser sight from my pistol in aligning the last set of frames, and used the water level to get them all level to the same reference....
One 1 gallon milk jug, inverted, lotsa cheap plastic tubing, a little red dye, and duct tape.......
After making the frames, added braces, bored a 1/4 inch hole at the reference point, shot the laser down the middle, jiggled the frames with the water level.....one man operation plus one housegirl with a funny look on her face.....:D

[bloggs68]

I've got an older Pacific Laser Systemes PLS2 laser
(http://www.amazon.com/PLS2-Self-Leveling-Palm-Laser/dp/B00006AVZD) which is self levelling and gives a horizontal line, vertical line or cross hair (all self leveling) and a locked on fixed cross hair. Pretty cheap for what you get. Great to set it up on a tripod projecting the cross hair which, if at the right height will pick up the centreline and a reference waterline making set up really simple.

I've been very happy with mine.

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