strip planking vs aging

[urisvan]

hello,
please look at this link.
http://www.gartsideboats.com/faq2.php
he doesn't like strip planking. Shortly he says that you can't prevent the wood shriking and expanding, even it is thin strip planked and covered with epoxy.

cheers

[dskira]

Some O-Jolle built strip planked (It seams it is the German who invented the strip plank) just before the war, in a classical fashion, just edge nailed, still sailing with the hull varnished.
I think the more simplier the strip plank is the better. Providing of course you have close space framing. The frames will be spaced twice the space of a normal carvel construction. This is my personal opinion about the spacing, not every body agree.
Between the strip, a thick varnish can be used or a type of Bostik 920 but it not mendatory. If you are in hot climat yes a good urethane sealand will be recommended.
I don't like the epoxy sheathing. It is not necessary. A normal glue will do, and good ring nails in bronze or galvanized (double dipped hot)
For large boat in set of the sheathing I will prefer two oposite diagonal heavy planking veeners on top of the strip glued, and then the last veener longitudinal also glued. I like to have the last diagonal veneer screwed all the way and into the frame. the planking longitudinal veener cover the head of the screws, and will be thourougly glued. It is better to have the longitudinal planking veneer not too wide.
A nice varnish will do.
But this is my two cents
Cheers
Daniel

[TeddyDiver]

As he says "Kilndried wood". That's the fault.. 5 years airdrying should do for softwoods. Hardwoods some more..

[Herman]

More on Strip Planking: Paul's Opinion
This section is taken from a letter to the editor of Watercraft magazine, in response to articles about strip planking as a good method of construction for the home builder. Strip planking appears to offer an easy route to planking the hull, because it does not require lining out the planking or constructing temporary jigs.

So that is an advantage: Simple and little framing required.

Some Problems with Strip Planking
•Time consuming and hard to repair
•Unstable
•Aesthetics
Time consuming and hard to repair
Any discussion of strip planking needs to address the serious problems inherent in the method. There are two main problems with strip planking. The big one is that is is not stable. You cannot edge glue a half acre of planking - regardless of how thoroughly kiln dried and edged grained it is - and without expecting trouble as temperature and moisture levels change. In a cold molded hull the fibre orientation is different in each layer, and each layer acts to stabilise the others. With strip planking the fibre orientation is in one direction only and the expansion is cumulative. Ah hah, you say, but that was before the miracle of epoxy resin. Now there is no transfer of moisture and hence no movement. Well I am afraid that is where we run smack onto the shoals that lie between the sales literature and real life. My experience is that a strip planked hull will shrink and crack in a most distressing manner if it is hauled out in the sun for too long, and I have seen everything from broken frames to the decks pushed up off the clamp as a result of swelling. Sure, epoxy resin is a wonderful coating and applied in sufficient thickness drastically slows the changes in moisture content, but I have plenty of evidence that it cannot prevent movement taking place in the wood entirely. I would certainly not rely on it to overcome the colossal tensions this form of construction engenders.

So do all strip planked boats suffer from broken frames and pushed up decks?

About the aestetic part, in a different part of his website he writes this abou t cold molded boats:

"The lack of framing and the flawless finish tend to give cold molded boats a too perfect, 'plastic' finish that often makes them indistinguishable from glass hulls."

So when a boat has a nice finish, it is not good, and when it has a more "robust" finish, it is not good either?

In contemplating a strip planked project, then, it is essential at the outset to devise a strategy to stabilize the structure. In small boats that will live mostly out of the water, sheathing inside and out with epoxy impregnated glass cloth works well. This is the method pioneered by the canoe builders and in small frameless hulls will produce a durable boat with an easily cleaned interior. It is surprising how soon the plank lines will start to show through the glass skin on such hulls. But the glass seems to be able to handle the stresses in light planking, and I haven't seen outright failures with this technique if done properly.

This is about those nice Canadian Canoes, I guess. Where the top strips are usually a contrasting wood colour. Some like them, some don't. He does.

On larger hulls I am not in favour of sheathing on both sides. That just looks like a rot trap to me. If you are an epoxy believer, you will say that since no water can get in, there is no way rot can get going. That assumes the only passage for water is through the laminate, but every time a through hull is installed or a fitting is bolted through the hull there is the potential for water to enter the core. When it does the owner will likely be oblivious until the problem is widespread. It is worth noting that ABS (American Bureau of Shipping) rules do not recognise solid wood, fully encapsulated, as structural below the waterline. This means they do not recognize the wood as contributing to the strength of the structure, because is is not likely to last. I don't see it makes any difference whether the resin is polyester or epoxy given the reasons above.

Bad installation of hardware is not only a problem for strip planked boats, but also for his beloved carvel or clinker built boats, or any wooden boat, or balsa cored boat. When installing hardware, on a cored or wooden boat, it is very important to decently seal the edges, or for higher loaded fittings, make a transfer to single skin. One of my clients uses epoxy pipes to lead the through-hull fittings of cooling water etc above the waterline, and only then install a stopcock. This way the stopcock can be changed or serviced without taking the boat out.
About ABS not recognising wood as a structural material under the waterline: Luckily they did not determine scantlings on older minesweepers...

In larger hulls with internal framing the glass sheathing is often applied only on the outside. To me it seems the height of optimism to think the enormous stresses in an edge glued hull can be controlled by a skin of glass glued to one face. I suppose if you get into biaxials and lay it on heavily enough you will eventually have a glass hull with a wood lining, and lick the problem that way, but that is hardly good engineering.

I have no idea of the situation in the USA, but at least in Holland the glass fabrics are applied inside and out, and before final framing goes in. Principles of cored construction, I guess.

There are other problems with this approach too. Traditional hull models often have large areas of solid deadwood which are difficult to sheath successfully. There is always movement here even if these members are themselves laminated. 'Zippers' in the glass are common here. And of course sheathing under the keel is very vulnerable to being torn on grounding.

This is a matter of engineering. Both of the keelson construction, and the laminate. However, many, primarily older, desingers have a tendency to say "the builder will figure it out" and seemingly today they will not...
Sheathing under the keel is highly dependant on boat design, but if a boat has a "groundable" keel, make sure it is protected well. Whether when traditional built, strip planked, or cold molded, or even polyester or steel. This problem is not specific for strip planked boats.

I think a better method for larger hulls is to use strip planking as the first layer of planking, and then follow it up with two or three layers of cold molded planking laid on the diagonal. We have found the method reliable, although it does not make as good use of the properties of the wood as a fully molded hull. A few test panels will clearly show the greater strength and stiffness of a fully cold molded laminate. However, extra thickness can be used to provide adequate panel stiffness.

About these test panels: Please do make them, and show us.

In all cases however the outer layer should run fore and aft. No matter how well the hull is sealed with epoxy, or even if there is a glass skin as well, it won't be long before plank lines begin to show. If a dark colour is used on the hull the plank lines show sooner and more clearly. Diagonal lines across the topside will neither gladden the heart nor improve the value of the investment.

Very much true. But also true on cold molded boats. No strip-plank bashing here.

Aesthetics
The second problem I have with strip planking is an aesthetic one. The majority of people who set out to build themselves a boat do so for the fun of it, because it is one of the most pleasurable things to do in life, or should be. With that in mind we should surely look for a method that will be enjoyable to do and a delight to behold throughout the process. For the long distance singlehander, this is more than mere sentiment. The pleasure that comes from opening the shop door in the morning is perhaps the single biggest factor in maintaining momentum through to the finish.

To my eye a strip planked hull is simply ugly. Because there is no compensation for girth differences, the planking cannot follow the natural lines of the hull. Instead it bunches up in the most offensive manner and on many hulls has to be cut down periodically so that a fresh start can be made. Compared to a nicely lined out carvel or cold molded hull the result is a dog's breakfast that must be concealed with paint at the first opportunity if morale is to be restored.

The fact that you feel a "naked" strip planked boat is ugly, is not a strong case for convincing other people not to do it. I think the Volkswagen Beetle is ugly. 25 million people clearly have another opinion...

Conclusion
In view of the amount of time and money involved in even a modest boat building project I would caution first time builders to weigh the options carefully and be particularly skeptical of 'instant' methods. Strip planking has its place, I use it from time to time myself, but I can honestly say that I have never built a strip planked boat that I did not wish at some stage I was building by another method.

My personal conclusion can be that all building methods have their advantages and drawbacks, and little quirks that need to be explored and discovered by the builder, perferably before building begins.

My personal opinion is that price of good quality red ceder, which is considered ideal for strip planking, is so expensive now (at least here) that I personally would opt for foam planking. But I cannot condemn others for not sharing that opinion.

[dskira]

Herman, do you own a Bugatti? Which model?
Urisvan you should talk seriously with Richard Apex1, he knows a lot and can guide you better than anybody else.
Cheers
Daniel

[Herman]

I have 2 Bugatti replicas of the "Bugatti Baby" also falsely called "Bugatti type 52" but no large car.

Do have a website, though: http://www.bugattibuilder.com

[PAR]

Strip planking has been around for at least 200 years, that I know of, likely longer. These are all traditional, what was once referred to as "narrow planked" or "set planked". These were edge fastened with and without something in the seams, which was usually shellac, lead or thick varnish. These boats held up well and still do to this day.

I'm not sure what Paul's biases are really based in, which are clearly displayed in his "preferred" building methods, but making blanket statements such as he, on strip planked hulls is frankly lacking fore sight and understanding of the method(s).

First of all there are at least a dozen different types of strip planking. Do all of them suck or only the ones he has issues with? Are all of them capable of producing too perfect of finishes or can some of them be considered poorly build and faired enough to qualify for his ideas of wooden boat perfection.

I guess we shouldn't have glued lapstrake boats either, because they are so difficult to repair too. Please . . .

What an arrogant, ill informed ass . . .

[dskira]

Originally Posted by PAR

Strip planking has been around for at least 200 years, that I know of, likely longer. These are all traditional, what was once referred to as "narrow planked" or "set planked". These were edge fastened with and without something in the seams, which was usually shellac, lead or thick varnish. These boats held up well and still do to this day.

I'm not sure what Paul's biases are really based in, which are clearly displayed in his "preferred" building methods, but making blanket statements such as he, on strip planked hulls is frankly lacking fore sight and understanding of the method(s).

First of all there are at least a dozen different types of strip planking. Do all of them suck or only the ones he has issues with? Are all of them capable of producing too perfect of finishes or can some of them be considered poorly build and faired enough to qualify for his ideas of wooden boat perfection.

I guess we shouldn't have glued lapstrake boats either, because they are so difficult to repair too. Please . . .

What an arrogant, ill informed ass . . .

PAR I have to agree with you. I read the Pauls' articles on strip planks long ago and I had the same reation as you. But you are more courageous than me! Yes it is an arrogant, ill informed ass.....................
Thank you PAR
Cheers
Daniel

[PAR]

Look just because some may have written books, get lots of column inches in the press and have seen some success, doesn't mean they are right. It just means they managed to tickle the proper butts to get some attention.

I do lot of lapstrake repair. Everyone says it's hard to do and it was the first few times I did, but once you get a handle on it, the work isn't that hard.

I think repairing cold molded is far more difficult then strip planking, so maybe we shouldn't build out of this method either. Cold molded hulls can be flawlessly finished (I have one) too, so people might think it's a plastic boat and the method should be banned.

Come on folks, don't buy into pissed off, ill informed, well covered in the press, old men, that are too set in their ways to adjust to or accept change in their lives or ideals. It's a fact of life. Change is the most essential element of all existence. Without change, the dinosaurs would still be here . . . Apparently, the well regarded Mr. Gartside is one of them.

[sabahcat]

Originally Posted by Herman

My personal opinion is that price of good quality red ceder, which is considered ideal for strip planking, is so expensive now (at least here) that I personally would opt for foam planking. But I cannot condemn others for not sharing that opinion.

A well written reply and I agree whole heartedly Herman

An Alternative to Western Red Cedar is KIRI.
Well worth a look and lighter than WRC as well

But not as strong sabah!

Though it is a phantastic material, it cannot replace WRC in every application.

Regards
Richard

[urisvan]

If Paul is right, strip planked boats should suffer from broken frames and pushed up decks frequently. Is it common?

And what do you think about mahogany for strip planking?

cheers
Ulas

[dskira]

Originally Posted by urisvan

If Paul is right, strip planked boats should suffer from broken frames and pushed up decks frequently. Is it common?

And what do you think about mahogany for strip planking?

cheers
Ulas

Using soft mahogany like okume is good but can be expensive, and the scantling should be raised by 10%. The fisnish can be realy nice if varnished.
Here we use atlantic cedar, it's very good and not expensive.
The only downside of strip plank against carvel will be you can allow knots, what ever they are. The strip are too small in section to have knots.
I never had a boat with broken frames because pushed against a deck. If the boat is a commercial boat, double sawn the frames and you can push the deck until it goes to the middle of the town.
If its a yacht, steam bent will stand hurrican force. As long the frames are close spaced and the structure well designed. The majors bulkead are not enough.

Cheers
Daniel

[Steve W]

Urisvan,whether mahogany is suitable for strip planking or not depends on the strip planking method,if it is a traditional edge glued and nailed over conventional framing and epoxy /glass sheathed on a heavier design then yes,we built a 64ft Lidgard design this way 30yrs ago although im somewhat distressed to find out according to the great Paul its probably sitting around with broken frames by now.However,if you are building a strip planked composite boat it is way heavier than you need unless of course you are building a heavy displacement boat by this method.
Apex,that kiri is "not as strong"as wrc is somewhat irrelevant in the type of construction that Sabbah uses, its a core and as such it is "stronger" than the common ones such as balsa or foam,maybe wrc is "stronger" but then mahogany is stronger than wrc but innapropriate for this form of construction."Strong" is a term i see used often when comparing different boatbuilding methods and materials and is fairly meaningless,what you need is "strong enough" kiri is strong enough for this method. Im not sure what application you would use wrc for other than the core..
Steve.

[PAR]

Steve W has it about right, there are so many different types of strip planking, we need to be talking apples to apples. Comparing a conventional edge nailed stripped hull over steamed frames isn't using the same engineering principles as one build with a cheap, light weight strip core that has heavy sheaths on both sides and no internal frames.

In most cases currently, people are using strip planking as a cored build (sandwich or composite), not a "narrow plank" build. In this regard, you can use pretty much anything you want for the strips, foam, cheap wood, cardboard, mashed potatoes, etc., so long as the peel and compression strengths meet minimum requirements at keeping the two skins in proper orientation to each other.

Okay, maybe mashed potatoes wouldn't have the compressive qualities necessary for the job, but if my aunt Rita's recipe was used, they'd easily have the peel strength when dry.