The ultimate guide to lofting.

[Hwyl]

https://youtu.be/PCuXeNkrpuY

[Peerie Maa]

Should have called the thread "Snort form" guide to lofting.

No explanation of about a week's work fairing the lines, followed by a week's work fairing the lofting.
Generally, if you have not made any errors of transcription, you don't aim to hit every tick mark except the "wrong" one. You aim to lay the line so that half of the marks lie on either side, so that you average the errors.
Then you start iterating round the fairing process, homing in on the correct lines.

P.S. I am more used to LL being level lines. If the baseline is parallel to the design water line, they can be waterlines in the bottom, and level lines in the topside. If the boat floats with drag, none of them are parallel to the DWL and so all of them are level lines.

[Tomcat]

People still loft? I think the only boat I even lofted was my first, a strip canoe I designed 40+ years ago, but basically I did it on the fly since every strip is a batten. Not recommending it. Since then, either computers or some of the many ways you can make shapely boats with "systems", or combinations thereof.

[Max F]

Yeah Tomcat

And why build a boat when computers can print out one for you...
Lofting can be good fun and gives a deeper understanding.

The best guide on lofting I have read so far is from the Gougeon Brothers

https://www.westsystem.com/the-gouge...-construction/

Straightforward and easy to follow.

Cheers
Max

[Zane Lewis]

Yes still loft out full size. Not many boat builders have a large enough plotter/printer/ cutter that would enable them to print out full size patterns.

Also probably a function of the plan. If it's a commercial production plan that many other boats have been built from then the risk is low.
If it's a one off or low volume plan it is great to get it out full size on the floor first.
Z

[John Meachen]

Yes still loft out full size. Not many boat builders have a large enough plotter/printer/ cutter that would enable them to print out full size patterns.

Also probably a function of the plan. If it's a commercial production plan that many other boats have been built from then the risk is low.
If it's a one off or low volume plan it is great to get it out full size on the floor first.
Z

Print patterns?These days the pros would just have them CNC cut directly and it isn't hard for an amateur to find a company that can do the same.I favour gaining an understanding of the traditional way of doing things but one's knees benefit from the modern approach.

[Peerie Maa]

Print patterns?These days the pros would just have them CNC cut directly and it isn't hard for an amateur to find a company that can do the same.I favour gaining an understanding of the traditional way of doing things but one's knees benefit from the modern approach.

That is OK if you can fair the lines in a CAD programme. If you don't have the software of the 'puter literacy, lofting is necessary.

[Tomcat]

Yeah Tomcat

And why build a boat when computers can print out one for you...
Lofting can be good fun and gives a deeper understanding.
Max

It wasn't an injunction against lofting, it was a pure statement of fact. I have built nearly 300' of small boats up to 24 feet, and never lofted a line. Just a backyard guy.

By the way, some smart people have figured out geometric methods whereby plans are developed perfectly lofted. I would call Newick smart, and he used the master mold system which was also used to some extend within Constant Camber. And you can nest the MM method into plywood boat system where the ply is relatively simple to configure and impose rounded surfaces where they are most useful. The master mold system can also be used to drive router jigs, not even requiring an investment in time money, or space into CNC to have a router that automatically cuts out parts. Though I prefer to draw the lines, jigsaw outside the lines, then use the trim bit with the MM to fair the frames to perfection.

I too am a big admirer of the Gougeons, and own all the editions of their book. I had great fun at one point, while visiting Bay City, Watson arranged it so I was able to survey both Adagio and Ollie. Of course the Gougeons built a lot of their personal boats using the Stressform method. This allows one to build the boat, then extract the lines, through a process of model making, if the boat even requires that. Of course the Gougeons also built many conventionally lofted boats for clients.

When people say that lofting gives them a deeper understanding... That sounds right, but from the perspective of a person who did not design the boat. I design some of my boats, and I never feel I would need lofting to re-explain them to me. I can see how if one started in the dark, it would be illuminating. However, as I say, 24 feet has been my limit. I could see myself building as large as 32 feet, but otherwise life is too short. I don't doubt that far more work in planing and visualizing a larger project would be useful. Lore is replete with stories of designers who went to the shop floor with an update and found the folks who work on their knees had already built it out. So point taken, just not in my world.

A great book on lofting I enjoyed was Rabl's book on Ship and Aircraft Fairing and Development. Subtitled for Draftsmen and Loftsmen, and Sheet Metal Workers. This takes the craft out of the 19th century and up to WWII methods, which is probably the apogee of manual methods and efficient small shop tactics, like projection. Sheet metal also gives some insight into plywood methods. It was published in 1941, and was still sold some time later. Online copies are available at the usual suspect sites, and that may be Ok given it's original date of publication. I paid $9.50 for my copy from the Nautical Mind.

[chas]

In 1977, as a newly apprenticed Boatbuilder I participated in the lofting of lines for this 48 foot on deck Tancook schooner. There are a lot of sweet curves and s-bends in this boat!

E85B42E0-3A02-4188-BAF6-9E92096C9525.jpg

Loved the experience, not to be missed. / Jim

[Ben Fuller]

Besides Rabl, Allan Vaitses is also good. https://www.amazon.com/Lofting-Allan.../dp/0937822558 Lofting is a great way to understand the boat's design as others have said. Why Paul Gartside has you loft his boats.

John G. used to loft his takeoffs and designs before drawing the lines. Often working from a half model. Helps make offsets more accurate.

[W Grabow]

Yeah Tomcat

And why build a boat when computers can print out one for you...
Lofting can be good fun and gives a deeper understanding.

The best guide on lofting I have read so far is from the Gougeon Brothers

https://www.westsystem.com/the-gouge...-construction/

Straightforward and easy to follow.

Cheers
Max

Similar to the question, "Why build a boat when you can buy one pre-made by professionals?"

[W Grabow]

Tomcat,
You obviously are well versed in boat design methods. But that doesn't mean that you should criticize what others may enjoy. I have never lofted a line on any of the eleven boats I have designed and built (14' to 20' long), but if you are not into computer programs, extensive mathematics, or the cost of CNC, lofting could be appealing.
Traditional boatbuilding methods hold very little appeal to me for a variety of reasons, but to each his own.