CHEAP 3D CAD ANARCHY

IStream

Super Anarchist
10,863
3,042
I assume by motor you mean "motor will a small outboard" - because any boat that sails and rows well won't plane with a big motor.  I designed (many decades ago now in 1994) a nesting rowing/sailing dinghy that motors well with the smallest motor you can buy. At the time a 3.3 HP 2 stroke Mercury but now the 3.5 4 strokes are so heavy I'd recommend the noisy Honda 2 HP motors.
FWIW, the Suzuki 2.5 four stroke is only 30lbs, about the same as the Honda now-2.5 air cooled unit but much quieter. 

 

Zonker

Super Anarchist
9,700
5,653
Canada
That's impressive.  The 3.5 Mercury I just used on another dinghy is 38 lbs and you notice it compared to lighter options.

 

LionessRacing

Super Anarchist
4,351
592
Myrtle Beach,
Interesting boat Zonker, the tubing gasket is an idea worthy of exploration.  
 

Haven’t done the structural engineering yet,  but was thinking of bolting through butted ribs much as you have done. 
 

willing to sacrifice ease of rowing, for better powered performance, happen to have a 2000 Honda 15 HP 4 stroke, at 100 lbs. 

had a further thought of a “console module” to allow wheel & controls vs. Tiller. 

 

Alex W

Super Anarchist
3,326
316
Seattle, WA
FWIW, the Suzuki 2.5 four stroke is only 30lbs, about the same as the Honda now-2.5 air cooled unit but much quieter. 
The EPCarry electric outboard is about 15lbs and probably has enough power to push any 10’ light and well designed rowboat close to hull speed.  You can also position the battery for best trim.  I have over 3 hour runtime with a roughly 10lb battery (not the stock battery that they use). 

 

LionessRacing

Super Anarchist
4,351
592
Myrtle Beach,
If you want to build a planing hull, then it must be a fair bit stronger and stiffened. How to hold the 2 pieces together at high speed will be more intersting.

Shameless plug dept.  Take my GV10 dinghy design, fit a middle bulkhead and cut in two.

https://www.boatbuildercentral.com/product/fast-garvey-10-boat-plans-gv10/

Or just buy the plans and use them as inspiration and structural guidance. 
Had the thought of a mating bulkhead. Will look at design. Happy to buy plans. 

 

Ncik

Super Anarchist
2,180
396
If I'm doing stitch and glue the surfaces will be pretty simple, could be flat to prove concept. I'd prefer something a bit prettier in long run.
I don't think sketchup will unroll your surfaces to flat patterns, nor tell  you if the surfaces are developable.

 

Steam Flyer

Sophisticated Yet Humble
44,256
9,609
Eastern NC
If I'm doing stitch and glue the surfaces will be pretty simple, could be flat to prove concept. I'd prefer something a bit prettier in long run.
I don't think sketchup will unroll your surfaces to flat patterns, nor tell  you if the surfaces are developable.
Correct, it will not.

Not a difficult exercise to do a projection onto a flat surface though; or to set up a series of triangles for the panels.

-DSK

 
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Ncik

Super Anarchist
2,180
396
Just use Rhino, the skills are the same but Rhino is better for this sort of project, including the ability to unroll your surfaces very easily.

Commands to use...

Line (to setup an overall grid and any straight features)

Curve (to create plan and profile outlines of gunwale, chines, keel, etc))

Crv2View (project plan and profile views to create a 3D curve)

DevLoft/DevSrf

UnrollSrf

DupBorder (to create an outline curve from unrolled surfaces)

OffsetSrf (to give your surfaces some thickness)

RebuildCrvNonUniform (to simply the crv2view result)

Fair

CurvatureGraph (to see how fair your input curves are during point editing)

 

Zonker

Super Anarchist
9,700
5,653
Canada
And Analyse -> Surface -> Curvature Analysis.  To see how developable your hull really is. Green is dead nuts flat. Blue is slight bending required.

image.png

 

Hunky

Member
56
5
NW Alaska
If you want to build a planing hull, then it must be a fair bit stronger and stiffened. How to hold the 2 pieces together at high speed will be more intersting.

Shameless plug dept.  Take my GV10 dinghy design, fit a middle bulkhead and cut in two.

https://www.boatbuildercentral.com/product/fast-garvey-10-boat-plans-gv10/

Or just buy the plans and use them as inspiration and structural guidance. 
Hey Zonker, nice plans. I like the 11' as a possible future build. But that aside and off the subject, I took a look at your 10' study plans from this link and the first photo shows a dinghy held in an arch structure that looks like fiberglassed pipe. I was thinking of building a similar arch to hold maybe a couple solar panels and I'm curious about how this one was made.. if it was yours. I was thinking about shipping (would have to be air freight so not cheap) up fiberglass 1.5" pipe and building out of that, with plenty of supports, or perhaps by some pvc pipe locally and wrap it up with fiberglass. Just curious about the scantlings on that arch, if you know.

As for the subject, I tried out Freecad, a 3d parametric program that has lots of amazing features for a free program. Coming from my job with Autocad Map, I though I could jump right in.. but it is a whole new paradigm and I had to hit the tutorials. Otherwise, maybe some of the other suggestions may be better suited.

 

Zonker

Super Anarchist
9,700
5,653
Canada
Hi, yes that was my boat. About a 14' fiberglass ladder was the horizontal part. Pretty light and lots of places to through bolt the solar panels or clamp to the rungs. And I could glass the uprights right to it (rather than a bolted connection). Could also be a foam sandwich panel. 

The angled uprights were surplus carbon/fiberglass windsurfer masts, bought for cheap on craigslist when they showed up. You want ones that are at least 65% CF or it might be too floppy. I notched the angled pieces to form the joint, and filleted the joints with thickened epoxy. The joints were made with thin (~1/2" / 1 cm) wide strips of unidirectional carbon fiber that were wet out on a table and then wrapped around the joints. Add peel ply and then electrical tape wrapped inside out to consolidate the joint. Worked well.

 

Hunky

Member
56
5
NW Alaska
Hi, yes that was my boat. About a 14' fiberglass ladder was the horizontal part.
Ha! Great idea on the ladder. How do people come up with this stuff..

I looked for windsurfer masts when trying to find rods to go from tiller to rudder heads. Found only one and it was local, thank goodness, and I ended up making a tube of carbon fiber for the other. Not quite as nice as the mast as far as I had some wrinkles in the one I made (used vacuum bag - big mistake) but it will work I think. Several layers of carbon uni and a carbon sleeve.

You've given me good info.. I'll have to decide what to do. Many thanks! 

 

Zonker

Super Anarchist
9,700
5,653
Canada
Best part is because it was painted white and hiding under the solar panels nobody noticed it was a ladder. :)

 

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