Amateur design insulting to pros?

[Scot McPherson]

there are plenty of videos on youtube showing failed ship launches....but if you take a design that's already out there and adjust it without altering the structure too much, you aren't going to break the design.

The boat you have drawn right there sobell looks like a buehler Stuart Little http://georgebuehler.com/Stuart Little.html but sloop rigged instead of cutter rigged.

You see, that's why I think it's a good idea to look at lots of designs rather than starting from scratch.

George may not design boats than win races, but he designs boats that are tough and safe as hell...not everyone is fond of his designs, because they think they are overly tough and over engineered...needlessly so, but honestly, unless you are racing, who cares if you lose a half a knot?

 

[Mr Efficiency]

When a total amateur attempts to design a boat (say, a sailboat < 20 feet), or a tiny houseboat/shantyboat -- a box, basically, on a scow hull or pontoons), is that an insult to professional naval architects and yacht designers who have been properly educated/schooled/apprenticed, etc.?

That might depend on the peevishness of said professional designers. I doubt many are going to go into a huff at the thought of an upstart creating his own design, they may think you are a dopey barsteward for doing it though, considering there are thousands of existing and proven designs available at reasonable cost. I think most professional designers would recognize that on occasion, self-taught types have come up with some very good designs, though usually not.

 

[upchurchmr]

Any reason you couldn't go back to your earlier plan of building the picaroon?
You could always make cosmetic changes to get closer to your sketch, and still have a well known, structurally sound boat with known sailing qualities.

 

[Scot McPherson]

How do you make joints too strong?

There is not such thing as too strong, just people who think it doesn't need to be that strong

 

[upchurchmr]

Too strong means extra material, extra weight.

Not good if you like better performance. Or just being able to tow your boat easily.

If one area is 2x stronger than another, then 1/2 that strength will never be used. Why go to the extra work?
There is the occasion (not typical) where extra strength ( or really stiffness) causes there to be more load, which can overload adjacent structure - resulting in failure.

 

[Scot McPherson]

Too strong means extra material, extra weight.

Not good if you like better performance. Or just being able to tow your boat easily.

If one area is 2x stronger than another, then 1/2 that strength will never be used. Why go to the extra work?
There is the occasion (not typical) where extra strength ( or really stiffness) causes there to be more load, which can overload adjacent structure - resulting in failure.

Unless you are racing, it's not a big deal. For a casual boater or cruiser, better to be too strong that not strong enough.

If the whole system is built to be tough, then there is no issue with being built too tough...

I would agree with you that a racing boat that barely holds itself together can be compromised by one part being so beefy that it compromises the strength of the adjecent structures, but that would have to be a pretty big delta.

for example, if you built phil bolgers designs that call for 1/4 inch ply and you built it with 1/2 inch instead, you might loose a 1/4 knot in speed, but the boat will be stiffer and tougher. but if you had a benataeu and you poured cement around the stuffing box of the rudder to strnegthen in, yes, you could cause the whole back end to tear itself apart.

 

[upchurchmr]

I suppose you don't trust the designers of your boats?

I don't like a tub, I don't like handling a heavy boat off a trailer, and I wouldn't want to pay twice for the plywood when I didn't need to.

The only racing boat I ever had survived being pushed far beyond what the normal safety first cruiser would ever have seen, and never had a failure.

Do Bolger's boats typically fail when built as designed?

 

[Sobell]

The boat you have drawn right there sobell looks like a buehler Stuart Little http://georgebuehler.com/Stuart Little.html but sloop rigged instead of cutter rigged.

You see, that's why I think it's a good idea to look at lots of designs rather than starting from scratch.

George may not design boats than win races, but he designs boats that are tough and safe as hell...not everyone is fond of his designs, because they think they are overly tough and over engineered...needlessly so, but honestly, unless you are racing, who cares if you lose a half a knot?

That's a pretty boat, and speed is not an issue for me. I don't want to take all day to get across the bay, but racing isn't an issue.

I've been noodling around on the forum and saw a reference to D.N. Goodchild website (sells books and old boat plans). I checked it out and my goodness, there are several little pocket cruiser that are so close to what I have in mind. These are plans for amateur builders that appeared in Popular Mechanics-style magazines decades ago. I may order some of them for my continuing education.

Here's a vintage tiny cruiser (16') for home builders, Blue Moon, that doesn't look like my design, but I really like it. However, I don't like the centerboard. I would prefer a bolted-on fin keel to a centerboard.

http://www.svensons.com/boat/?p=SailBoats/BlueMoon

The main reason for designing my boat myself is that most wonderful old vintage designs specify not-wonderful old vintage building methods. I want a simple technique, such as the ones used to build Stevenson Project boats -- very simple plywood construction with minimal framing and fiberglass everywhere. I think it's interesting that Blue Moon, the plans for which were published in 1972 or so, which has quite a bit of framing, is covered in fiberglass, like the Stevenson boats.

 

[PAR]

There are plenty of well founded designs that are likely to provide exactly what you're looking for, just needing some aesthetic upgrades to suit your whims. Designing a 20' sailboat isn't a great feat, though you sure can build an ill handling beast if you don't know what you're doing. Most of these older designs can be converted to taped seam or other build type, with some education or help. Pick up the book "Elements of Boat Strength" to get a handle on some of these conversion processes and a general idea of what might be involved with your self designing a fresh new boat.

Find a design that is close and make the appropriate modifications, so it suits your needs. Try to avoid reshaping the hull other than a 10% - 15% straight stretch (if desired) and you'll probably float upright come launch day. Screw with the hull shapes and rig balance very much and you might have extreme difficulty, trying to quantify any changes and modifications, to address issues (there's always issues).

Lastly, yes there sure is such a thing as overly or too strong. A perfectly engineered structure will suddenly, explode when it reaches its failure point. This means all the elements of the structure were sized appropriately for their loads, no heavier than necessary and contributing equally to the whole. If an element is "too" strong, it will transmit higher loading to less substantial surrounding elements, forcing them to tolerate more than they can take and now you have an often difficult to diagnose, localized failure.

 

[RHP]

When a total amateur attempts to design a boat (say, a sailboat < 20 feet), or a tiny houseboat/shantyboat -- a box, basically, on a scow hull or pontoons), is that an insult to professional naval architects and yacht designers who have been properly educated/schooled/apprenticed, etc.?

What an odd question. 'Amatuers' like Dr T Harrison Butler must be spinning in their graves.

 

[hoytedow]

How do you make joints too strong?

Weight is a factor to consider. I have used heavy stock to buttress seams which would have served as well without the additional weight. The seam in question could have performed just as well with stitch and glue technique without several cubic inches of additional wood. It was a simple, sloppy and lazy way of slapping two pieces of plywood together. I know better now.

 

[Sobell]

I've been looking at newer designs that use more advanced building methods, and the issue I have is that many (not all) of the boats look modern, and some ultramodern. I want traditional, aka vintage.

There are a lot of us throwbacks out here who love vintage stuff... I belong to several mid-century modern (houses, furniture) and several vintage travel trailer groups on Facebook, one of them devoted to restoration. Old campers are virtually always in terrible shape and often require "frame-up" rebuilding. Some people update them but most want them to look as original as possible. Restoring and camping in vintage trailers, and holding rallies to display them, is a craze. Some manufacturers have taken note, and now have "reissues" that look like campers from the 1950s (kind of), but using updated materials and methods. Most vintage devotees don't like them.

I know about that because before I build a boat, I'm going to build a small travel trailer. Would love to build the little round one, but that shape, while it reduces windage, restricts what you can do inside. I will likely build the little box -- it accommodates my pet floorplan best -- and put some vintage elements on it, like the crank-out aluminum windows.

Interesting note about the round one -- named Terra Cruiser. The 1940 magazine article that features it is authored by William Jackson -- very likely the prolific boat designer of that era. I wonder if he designed the camper, as well...
http://tnttt.com/VintagePlans/14'caravan.pdf

Anyway, I said all that to ask this ... why can't this little boat be constructed using stitch and glue? That is THE boatbuilding method these days, right?

This is another "vintage-magazine" plan, and I wonder if it is also a William Jackson design. He designed Star-Lite and Gypsy, deepwater boats, but he also designed dozens of small sailboats and motorboats. I wish more were known about him, and more of his designs brought into the 21st century...

 

[PAR]

What an odd question. 'Amatuers' like Dr T Harrison Butler must be spinning in their graves.

Butler was anything but an amiture designer. He drew some of the sweetest WL's I've ever seen and well understood the principles and mathematics involved. Given his education, he knew the value of understanding, what was involved and performed the research in a day, where no computer help was available.

There are lots of designs (again) available, you've just not looked very hard. Hell, look at my gallery and you'll see designs, much like what you want. You can have both modern build methods and performance, with the look of whatever (or nearly so) you'd like.

 

[tdem]

Have you looked at the Yachting Monthly Senior? Looks similar to your drawing and has been redrawn for modern construction methods.

 

[Sobell]

Have you looked at the Yachting Monthly Senior? Looks similar to your drawing and has been redrawn for modern construction methods.

I like it. I'll have to learn more about it.