65- by 32-foot catamaran 3200sqft of living space

MisterMoon

Super Anarchist
2,668
394
To set things straight HR didn't threaten to shoot anyone the people on this page brought up shootings
While you are setting things straight:

1) how thick is the skin on the hull?

2) what is your frame and stringer spacing?

3) what are the frame dimensions? By that i mean sided and molded dimensions. If you don't know what that means, look it up.

4) how is the skin fastened to the frames and stringers?

5) and finally, why didn't you think to bend the plywood? Bending ply into conical and cylindrical shapes really stiffens it up.

 

tls

Anarchist
693
0
I don't understand why everyone in the thread is fixated on the plywood grade. Lots of folks have build boats with exterior grade rather than marine plywood. . . . .While Marine and exterior grade are not the same stuff, the fact that they used CDX, by itself, does not give us any information about whether this boat will break up in a seaway or under tow.
Wow, tls, you fail Wood Engineering Technology. You need to back up and study a little more. Different specs of plywood are rated for different structural loadings and different stress directions as well as for moisture and rot resistance. The fact that they used CDX by itself does indeed tell everything an experienced wood guy needs to know about how likely this 65' foot catamaran will break up in a seaway or a tow. You are arguing from a place of extreme ignorance, my good sir.
You have failed to bring an argument, only insults. You can definitely build a strong boat out of exterior grade (non-marine) plywood, including CDX. Lots of folks have done it. It isn't necessarily a good idea, but it does not tell you anything about whether the boat will fall apart. That has more to do with engineering and construction.

I am pretty sure I've never failed Wood Engineering Technology, but that may be because that course was never offered in our university's engineering program. Of course that means nothing to an "experienced wood guy" like yourself. You've probably looked at the designs of 1000's of engineered wood products.
Wow,

are you a wofsie sock by any chance?? If not, Mikey sick em.......
I am not a sock puppet as far as I know. I've been on SA since 2004, but mostly lurk.

I just don't think HF would fare any better if they had used 3/8th marine ply rather than CDX. In the end it isn't going to make any difference. Swapping out for a grade that offers 20% more bending stiffness capacity or 30% more axial compression strength is within the rounding error for this design. Worrying about the rot resistance of the plywood seems misguided given that nothing about the HF is designed for a 20 year working life. More generally, for any strength/stiffness properties of marine ply, it is possible to exceed those with CDX. Although the CDX would require a greater thickness, it may be a less expensive way to get the required strength or stiffness if materials costs are your primary concern.

The fact that CDX is not marine grade ply is clearly true. CDX is inferior in every way but price. Lots of successful boats have been made with exterior grade (rather than marine grade) plywood. This is discussed in most books on plywood boatbuilding and in the West Systems training materials. E-glass and poly resin construction is clearly inferior to carbon/epoxy but that does not mean it is impossible to build a strong boat in glass/poly. PBO rigging is better than manila rope rigging, but that does not imply that every boat with manila rigging would be unsafe. Thousands of boats have made ocean passages with natural fiber rigging, although it isn't something I would recommend.

Using CDX does not tell us much about the problem with this boat, although it does suggest that the builder was either uninformed about alternative materials, or he valued materials costs above all other considerations (longevity, ease of construction, durability, etc).

 
On being Inebriated. (FUBAR)

I do SO love it. Inebriation is SO helpful... (FUBAR even more so)

On gin, on Scotch, on Irish.... I simply don't care. Being slightly (well, let's face it) or Totally "Effed Youp" is such a wonderful state of mind.

Who would want to be a rationally sober persona when you could be sloshed outta yer' mind? It's a comfortable and encompassing place, much like living in a feather pillow... All nastiness repelled, all softness included, much like being seduced in a Victorian boudior of lace and air, drenched in candlelight and suffused with perception and an acceptance of all things stupid...

Which is what is required to accept and understand this stupidity.

 

tls

Anarchist
693
0
Douglas Fir AC marine grade is the bare minimum you can get away with and that will check like a mad man, which someone already mentioned.
Under what type of loading would 3/4" CD Exterior 5-ply fail, yet 1/2" AC marine 5-ply would not fail? Bending? tension? compression?

You cannot usually determine how strong a structure is based on the grade of lumber used without knowing more about the structure.

 

Boston1

Super Anarchist
3,653
0
BF colorado
Sounds like there's going to be some assault charges after all. In which case bail isn't going to help him much, given he's in for failure to appear on lesser charges, although around here driving on suspension is an automatic 20 days. So it might be a while before we see Rod again.

Michael, its up to you son. Drag the boat to the back bay and keep it floating till Rod gets back. Best of luck.

Try and see past the guff and just ask, I'm sure there are plenty here who will offer sound advice in how to get to the back bay area and I've heard several suggestions as to what harbor you might find shelter in. I do hope you seriously consider this advice.

Best of luck
B

 

MisterMoon

Super Anarchist
2,668
394
3/8s was only used interior 1/2 is minimum to 5/8 full rolls of glass used to cover 48 on frame 6 on stringers
Thanks for the response.

Making sure I understand: the hull skin is 1/2 to 5/8 thick, sheathed with a single layer of glass? Do you know what weight was the glass?

The frames are on 48" centers, correct?

The stringers are spaced @ 6" intervals on the frames. Are the stringers standard 2x4 lumber or something else?

 
Assault - apprenhsion of an unlawful battery. Differs from fear. .

Battery - actually being touched without permission. Generally with intent to harm but intent is not required.

Biting a finger - battery.

 

silent bob

Super Anarchist
8,931
1,437
New Jersey
I don't know about Marin, but in L.A., Operating W/O a Licence barely gets you a ticket. There are about 1 million Illegals here driving without a licence or insurance. And as far as biting someone's finger, might just get you a thump with the Rodney King Memorial Baton, but bot much time in the graybar hotel.

 

bluenosejr

New member
23
0
3/8s was only used interior 1/2 is minimum to 5/8 full rolls of glass used to cover 48 on frame 6 on stringers
post-180-015338200%201318620417_thumb.jpg


as this shows the 'frames' appear to be 48" on center and the 'stringer' appear to be 6" on center.

no indication of how the floors are to be installed.

 
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Assault - apprenhsion of an unlawful battery. Differs from fear. .

Battery - actually being touched without permission. Generally with intent to harm but intent is not required.

Biting a finger - battery.

gutta wonder if the guy bit on the middle finger

just might have been taking a leak around the time :eek:

bet when HR saw that little serpent in the harbor master's grip this song ran through his mind

and he lost control (who wouldn't after living on Beans & Cheese and your Crapper Key don't work no-mo) :eek:



Lucky for their subscribers they didn't post a link

Hot Rod I got a deal for you

"IF" You admit to placing 5lbs of shot into 6 tubes of the ORACLE AC-45's w/o permission

"OR" Better yet having been paid by E.B, B.B., D.M. or C.L. hell even Snaggletooth

"You Shall be Off to HI" First ClASS

PM the AC-IJ for details ;)

 
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βhyde

Super Anarchist
8,358
1,958
Beside Myself
3/8s was only used interior 1/2 is minimum to 5/8 full rolls of glass used to cover 48 on frame 6 on stringers
Michael,

For the love of god, once your dad is out, and I hope he will be soon, head to the Delta. You cannot stay in Marin. You will find nothing but trouble there. The Delta is where you need to be. No one will fuck with you there. Arrange a tow as soon as possible and move. In the right conditions you can make it using the Bayliner. Get someone to help you with the tide tables and the winds.

 


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