In search of the prefect Proa

[Alex.A]

Option of both is good - demountable helps, even if it lives parked - can take it home to work on or cheap storage.... but not viable for most without a yard or the space to do it. For building far from water it does make a lot of sense - back to simple, if time consuming methods... or ingenius, if exspensive. I cant wait to see Fanies system - as he wants the same for a largish cat.
I had another (stupid? ) idea - a double proa - no not a tri - have 2 ama's/floats to one side....
could both be built lighter and smaller than a single and make taking apart easier? Rig mounted between the two or on the closer one. Makes me think of training wheels tho !! Even make them have a variable spacing? But WTW or Pac? Or both?

 

[Inquisitor]

Your video just repeats the same frame for me. ):

Did you make all of this in Sketchup?

Bad Video - I created the video last night at home. I only have Windows 7 at home and it worked fine. I just tried it at work on a Windows XP machine and it blew cookies. I'll see what I can do.

Software - I mainly use SketchUp and DelftShip Free. Here is a more extensive and detailed list of software I use. For the video, I'm now using ffmpeg to take the images and translate them into video.

Iterations - I wouldn't feel too bad about bouncing all over the place. As you see... from the predecessor Z40, I too was working on a catamaran. I probably went through at least twenty iterations on the catamaran. Hell!... for that matter... this current Proa design is 6-5. Meaning... Its the sixth version, I started from scratch and the fifth off shoot along the way.

 

[Inquisitor]

More software.

Oh! I almost forgot.

I have recently added Michlet and Godzilla to my list of software. Delftship's speed predictions pretty much only go up to hull speed. For a 40' hull... it peters out around 9 knots. Michlet will take it on up to just about any realistic speed. It doesn't account for any semi planing effects, so, if anything, it should be predicting pessimistic friction loads at higher speeds.

I'll let you know!

 

[Inquisitor]

I too, am looking to make this with minimal expense. Although I am in disagreement with many on this forum, I don't include the cost of my labor. I happen to consider my time on this as enjoyable and part of the hobby. If I hated wood working (or this design work for that matter) I guess, I would consider it part of the cost. At which point... this would be a very expensive boat!

But, as I see, we are in similar shoes... you might want to consider the Lindsay Lord strip plank technique as described by Dave Gerr. It proports to make an extremely light and inexpensive hull.

 

[Alex.A]

I have the "luxury" of working from home - and the time (explains why i'm on the net all the time...) as well as space for such a project. I too find the designing enjoyable - if challenging and taking longer than initially thought - but learning lots along the way! Unfortunately i have an old G4 Mac and design software is limitted - as are my skills!! Trying blender.... until now all maths and drawing done 'old style'. Might be quicker than learning to use blender tho'
Have pretty much finished hull design for a cat - but still not sure that it will be a cat!?! Designed for ply - have (what i think is) a clever/easy way to build..... we'll see when i get there. Waiting for warmer weather so can build a 15' version to try various idea's out on - test bed. In the mean time i fiddle and change minor details and ask stupid questions....
People here like to see you are serious - and have thought it out and are trying. Humility is good too? They do after all know lots more than i do and all help and idea's are hard earned by others so that we may learn....and not repeat mistakes!! I dont always agree - and build models and "play" to test - rather find out what is viable before wasting a lot of time and money!!!!!!!!
But if people dont try new things, we dont advance

 

[Inquisitor]

The Inquisition Begins

I will be starting the construction of the 60' lee hull this weekend. That part of the design hasn't changed. That's the beautiful thing about these Proa's! Unlike monohulls (or even catamarans) many things are just plainly decoupled. So I've fixed the lee hull and I'm off to the basement to make sawdust! I've got plenty of time to refine the rest of the boat.

We were talking about prices...

• free - made section cuts in SketchUp of the lee hull.
• free - reduced them by the wall thickness derived from the Lindsay Lord / Dave Gerr scantling.
• free - made a grid pattern overlay over all of them.
• almost free - printed them out on plain typing paper on the laser printer.
• almost free - taped them together using the grid to keep everything aligned.

I'd like to take credit for forethought... It turns out, I can cut 3 sections out of each 4'x8' sheet of plywood... but sometimes Blind Dumb Luck intervenes!

• $85 - I need 10 sheets of 4x8 OSB (@ $7.27 apiece) to make all the sacrificial male molds. I'll let Homer's Depot cut them in thirds for me.
• $300 - I need plenty of wood to make the strips, but the Lindsay Lord technique is very tolerant of wood quality. There is a very good section on wood species recommendations in Dave Gerr's book. I'm still debating between plain southern white pine and cyprus.
• ~$100 - epoxy to glue it together.
• ~$100 - for miscellaneous saw blades that I need to make dull.

So for ~$500 bucks (and about a $million worth of my time) I'm busy for the next six months making sawdust and a 60' hull.

After the wordworking project... I'll need...

• $1200 worth of Dynel 4 oz cloth
• $400 worth of epoxy.
• $300 Although not specified yet, I'll need some fiberglass and more epoxy to make internal structure to connect the cross beams and/or mast(s).

So for... ~$2500 I'll have the lee hull ready for painting.

This is a lot of money, but in the grand scheme of things... I'm comparing it to somewhere betwee a Lagoon 440 at $750,000 and a Gunboat 48 at $4M. And I should be able to run with the Gunboat in a race!

 

[Alex.A]

Post build pics!!!! Go for it.

 

[Inquisitor]

Trailering articulations fixed.

I've updated the video on the previous post. It seems to work on Windows 7 and Windows XP now. Don't know if it will work in the Mac world. Let me know!

 

[Alex.A]

Yeah - plays no problems.

 

[Inquisitor]

...So I looked into basically a longer F-39, but more like a 55. Having the amas fold under is convenient.

I wanted to let you know... if you start thinking back to 55 feet, you might have troubles unless you are willing to get special licenses and permits $$$. I did a lot of reseach on this... I'll try to find the notes if you're interested... but the summary is...

All states define their own limits. BUT the fed does specify what is allowed on the Interstate system and most of the states are pretty much the same. Those federal Interstate limits are:

40'x8.5'x13.5' and trailer and tow vehicle can't be over 65' combined. Yes, you can exceed them and probably never get caught, but if you are ever in an accident, you'll be cited and probably sued. Oh! And many state back this way (east) go down to 8' wide. I have a full state by state chart somewhere.

 

[cavalier mk2]

Go for the cyprus, it will be lighter less brittle and nicer to fair. It is a traditional planking wood for a reason.

 

[Inquisitor]

Go for the cyprus, it will be lighter less brittle and nicer to fair. It is a traditional planking wood for a reason.

Thank you for the information. I've never worked with cyprus. I read in Dave Gerr's book that it was very good as you said and also for it water tolerance. Although, I guess the water tolerance isn't really a factor since, I'll have it fully epoxied all around and sheathed.

My only reason for consideration of the white pine is... the scantling calls out a wood density between 24 and 32 lbs/cu-ft. The white pine I've measured is right at 24. I haven't measured the Cyprus, but DG say it starts out at 34 lbs/cu-ft. That adds at least 650 pounds to the boat.

The cyprus is probably on the green side, so me measuring it now would be probably be higher than 34. You mentioned its lighter... have you ever measured what cyprus is running these days when its good and dry?

 

[bearflag]

Be that as it may, 20m (in parts) is sufficient to get my boat to the water without a special use permit.

http://www.dot.ca.gov/hq/traffops/trucks/exemptions/auto-boat.html

You can move "almost" anything of any sort of dimension with special oversize permits. The federal law and most state laws are more concerned with regular commercial loads, and in general "may" (not will persay) offer special permits to move whatever you need, it just won't be cheap, as you may have to close down highways, remove powerlines, etc etc.

DISCLAIMER: Always better to check with every municipality you need to ship the thing thru before you build it.

I live right next to the Ronald Reagan Presidential Library, and they rolled the 1980s era 707 Airforce 1 from Burbank to right down the street. They carried it in 3 sections, whole fuselage, right wing, left wing, and then reassembled it on location.

There is video of it somewhere, I just can't find it...

http://www.youtube.com/watch?v=dJHxnhleswY

Like I said though, I have no intention of making my boat "trailerable" in the most common sense.

Hell from a design perspective it'd be nice to have a "farrier" style collapsing trimaran, just for docking the beast in the marina, or for storing it in a shed/hangar. Could mean the difference between getting a slip or not.

 

[bearflag]

here we go... (california only)

http://www.greenhornetpilotcars.com/California.html

When Escorts are Needed: #Escorts
Width over 12' 1 Front
Lenght 120' to 135' 1 or more (depends on location)
Lenght over 100' in LA city 2 (Front & Rear)
Width over 14' Minimum 3
(2 Front & 1 Rear)
2+ 100' in LA county




Maybe 60 feet shouldn't be my upper limit? (heh)

 

[cavalier mk2]

My wood resource lists white pine at 24lbs/cu-ft. and cyprus at 28lbs/cu-ft. Both species are listed as not strong but durable with the cyprus having the edge in rot resistance. However, cyprus can have hard and soft streaks because of the difference between summer and winter wood so if you can't pick through it maybe pine is the best choice. Is it much less expensive where you are? In my part of the woods I usually use red cedar, Douglas Fir and Sitka Spruce depending on the job. Wherever you are local woods are the way to go.