Custom Paul Mann

[fishskipper]

Cheeks, I wasn't going to come back to this thread, but I just have to ask to please back up what you say. I don't mean to be disrespectful, but to just say its a big no no, with out facts means nothing... where have you seen this process fail? Theres only about three boat builders in Wilmington and about a dozen here. Is your opinion based on schooling, experience or did someone just tell you this?

[cheeks]

Originally Posted by fishskipper

Making accusations is easy, but backing them is the hard part. I certainly don't know all about building boats and I'm open minded enough to learn something new, but don't just tell me its not a good idea or its not smart or its ignorant with out facts to back it up!

I did. Please reread post #19 and #24 of this thread. If you need further explination I will happy to do the best I can.
Every time I have tried to expalin to you why lumber shrinks and swells you simply reply with "No it doesn't".

[cheeks]

Here you go.

Originally Posted by cheeks

Wood shrinks and swells radially, tangential to the grain. Wood does not shrink along the length of the grain.(It actually does slightly but not enough to matter in most situations.) Thus if you leave a 8 foot long board outside in the weather it will still be 8 feet long regardless of chages in moisture content. However it will cup, bow and twist like crazy. All wood will shrink and swell with changes in moisture content. The amount it shrinks and swells is reffered to as dimensional stability. Plywood is a modern material that over comes this by using thin veeners a right angles to one another so that the wood shrinks and swells in differrent directions counter balancing itself. Thus plywood is dimensionally stable.

So here is the problem. When you attach a dimensionally unstable wood(in this case Juniper planks) to plywood with a nonflexible adhesive such as epoxy they are going to destroy each other. Resulting in delamination.

[cheeks]

And again

Originally Posted by cheeks

Plank on frame and Lapsrake were the way boats were built before we had gap filing glues such as epoxy. Epoxy opened up a whole new world of possibillities in the sixties. There are alot of ways to build a "cold molded" boat and alot of good techniques out there.

Plank on Frame is the old school way to build a Carolina Boat. A few guys still build this way. If you want to see pictures check out the Bobby Sullivan thread. There is nothing wrong with plank on frame boats. They have a few draw backs. They are heavy because all of those frames and you have to cork the seems. You also must be careful the fastners are not eaten away by electrolosis. A "hot" marina can cause big problems for plank boats.

What you see in those photos is a poorly built plank boat beeing sheethed with plywood. I am at a complete loss for why anyone would do this. There is no reason too. Forgeting the delamination problem for a minute, why would you want the additional weight of the frames. If you strip planked the boat instead you would only need half as many frames.

Plank on frame boats require alot of skill and skilled labor. You have to Line off every single plank. Every single plank is "hogged" or planed to fit the frames it lays on. This is a skill that seperates the men form the boys. Truly an art form that requires years of experience. Especially on carolina boats with extreme flair.

They are attempting to get around lining off by just running four inch planks(I assume scarfed together) using fastners at each frame. Then covering the whole boat with plywood. Ahhhh........... and this is where these boys have created a huge problem for themselves. You have to plank with flatsawn boards or you will split the plank by putting fastners in the same grain line splitting the plank. Even if you use quatersawn it wouldn't work with planks that wide. Flatsawn boards are the least dimensionally stable. Trying to sheeth them with plywood is insanity.

[clt_capt]

Originally Posted by cheeks

Correct.

So - maybe I'm missing the point here - Looks to me like the Paul Mann in question is planked, with Plywood laminated to the plank and then glassed over.

I believe I understand what you are saying about plywood over plank - West Systems Epoxy is not (very) flexible and IF there is movement or swelling of the planks in differential to the plywood, then the epoxy can pull away chunks of wood, causing a delamination of the plywood and plank... Am I on track with what you are saying?

Every boat is a compromise of rigidity, flexibility, longevity, weight, cost, etc. To say that this is the "worst" example of boat building is pretty strong - I would hazard to guess that you haven't looked carefully at the way many expensive "fiberglass" boats are constructed - Just what is that high build putty that Sea Ray uses between the skins? What about foam coring materials? If wood gets wet, it may rot over time, but wet foam? POOF
How about high build materials like coremat - Not a whole lot of strength there.


So - What is your real point???

[Glenn W]

Originally Posted by iguana1

Fishskipper,
In general this discussion does make me wonder why you wouldn't just do the whole thing out of plywood (other than it wouldn't look like F1s boat)

I may not know much about the science of wood/epoxy bonding & lamination and I sure don't know much about the art of boat building, but I do know there are usually several ways to build most anything--- none of which is the end all, be all way to do things. Perhaps the best quote I've ever heard on boat building came from Rick Scarborough:

"Everyone thinks that their way is right, if you don't, you're in the wrong business."

In the same interview, Scarborough went on to say:

"I will not build boats on a jig (mold). I just don't feel like they're as good as a boat built from the keel up. I also don't want to go to the plyboard like everyone else. I know it's lighter, but I honestly feel that juniper will outlast plyboard every time,"

Perhaps the opposite end of the Specrum is another highly respected builder, Buddy Smith of Island Boat Works in Hatteras. These boats are light and lightning fast cold moldeed and constructed of 3/8 inch plywood/Kevlar composite with two layers s of Nytex on the outside.

The point is, there are varying schools of thought on how a wooden core boat should be constructed as well as what materials should be used. These differences of opinion come from the very best custom boat builders in the business, yet they tend to respect and appreciate other's techniques.

Unless Cheeks can provide reasonable evidence that the likes of Paul Mann, Ricky Scarborough, Buddy Cannady, and Irving Forbes don't know how to build a quality boat that performs and lasts, I sugget that no credibility be given to anything he has typed.

With this, the Ball is in your court now Big Dog------

[cheeks]

Originally Posted by clt_capt

I believe I understand what you are saying about plywood over plank - West Systems Epoxy is not (very) flexible and IF there is movement or swelling of the planks in differential to the plywood, then the epoxy can pull away chunks of wood, causing a delamination of the plywood and plank... Am I on track with what you are saying?

Yes, you are.

[fishskipper]

Cheeks,
This rig a 1971 Sheldon Midgett was never glassed until two years ago and only to the water line.... Nothing has moved, swelled or cracked. Now above the water line is another story .... it moves! Now... when we glass up to the rub rail
this will keep her from moving, as has been done with many boats. So many in my mind I can't even begin to name them all. .. Just because you fasten okume plywood doesn't change that fact. Please, once again if you have proof that it does then lets hear about it!!!!

[cheeks]

Originally Posted by clt_capt

To say that this is the "worst" example of boat building is pretty strong -

Yeah, that is a statement I wish I could reword a little. I wish I had never said it because I came across like a Blowhard which is not my nature or intention.

[fishskipper]

oops forgot to resize... sorry