Strip planking questions

[JordieS]

Hi again everyone,

I have become a new addicted member on a quest for knowledge.

I was wondering what the best wood would be for a hull. I am getting some ideas in my head to build a strip plank boat but I still have a few questions about strip planking.

What would would be the best to use for a 5 metre boat? Mahogany, Red Cedar?
Are strip planks made of plywood or are they just really small/long planks of the wood?

I've been spending ages on the internet to find a supplier in Australia of Red Cedar and Mahogany but just can't really find any, does anyone have a supplier?

How thick should the strips be?

I will probably come up with more questions so I shall ask them later.

This forum has so much knowledge and experience and I would really appreciate if someone could take a bit of time out of their day to answer my (what probably seem dumb) questions.

Thanks

[gonzo]

Strip planks are usually solid wood. The type of construction lends itself to use lower quality wood. The thickness of the strips depends on the design and you will find them on the building plans. There are plenty of local wood species you can use. For example, pine.

[PAR]

There are several different strip plank methods ranging from a pure traditional type, which is pretty much a narrow plank carvel, to the Lord method, which is a true sandwich composite method.

The species type and planking thicknesses depend on the method and the design. Planking can range from a few mm thick to a few inches. There are a dozens of variables to consider with these methods. A 15 meter boat will have strips in the 1/2" (13 mm) range, though they could be thicker or thinner depending on the version of strip planked you'll be using.

[peter radclyffe]

How big a boat can built with glued lap construction ?

[sean-nós]

I'm doing mine with planks over plywood, you can see it here the gaps are filled with epoxy mixed with graphite power http://s753.photobucket.com/albums/x...view=slideshow

[Eric Sponberg]

You would do best to buy a copy of "The Gougeon Brothers on Boat Construction" from your nearest WEST System epoxy resin supplier, or direct from The Gougeon Brothers. It will tell you everything you need to know about boat building in various methods using epoxy resin, including how to plan and estimate the cost and time for construction, and which woods should be used where.

Eric

[PAR]

The book Eric mentions will cover most of the strip plank methods, but not all. The best advise you can receive is to build to the plans, as the designer has engineered it. If attempting to design your own scantlings, Dave Geer's book "The Elements of Boat Strength" would be useful, though your questions seem basic enough, that you should consider more study in the other areas of yacht design as well.

[JordieS]

Ok thank you guys, I have designed a boat that I want to build as a scale model first so now my biggest challenge is somehow printing out the frame lines off of Rhino.

Thanks again for all your help

[Corley]

Strip planking is usually very thin planks applied fore and aft it has all of its fibres running in that orientation so will require cross grain reinforcement for strength. Popular choices for strip plank in Australia are WRC and plantation grown paulownia. Keep in mind that since boats taper towards the end not all of the strips are able to go the full length of the boat. You need to install "stealer" planks which are shorter and taper on the ends to fill the wider parts of the boats planking.

[PAR]

Well, that's one way of doing things Corley. JordieS, post some lines of your design and provide a weight estimate, as well as the basic dimensions, so we can talk apples to apples. I'll assume the partial lines you posted in the frames thread, is of this same design. In this case, I'd suggest you're not well suited to a strip plank build, but rather a sheet goods build, be that foam core, plywood metal, etc.

[JordieS]

Yes it's the same one drawn in the frames thread, and at the moment I'm only doing a little scale model for the fun of it (also because I'm new), I think the method I want to use is the same as this guys; https://sites.google.com/site/midnig...ject/september

What method is that called as you can see in the photos?

The model is 111.5 cm long and has a ~40cm beam and ~15cm tall

Thanks everyone, it's appreciated very much

[PAR]

Where are the "centers" on your boat? More specifically, where is the CG in relationship to the LWL? Have you preformed any of the usual preliminary hydrostatics?

The build method shown on that site (I'm assuming as I didn't watch the whole thing) is the typical Rivirea (Glen-L) cold molded build. It's three diagonal veneers and a pain is the butt to build like this, though can be light and strong (not if built to the Glen-L plans though).

[Corley]

Of course PAR is correct what I'm describing is simply one method of strip planking and thats not to say its superior to other methods.

I'd have to concur with PAR on building triple diagonal, I'm building a triple diagonal hull now and would not use the method unless well, your incredibly patient, planking progress is slow and its very labour intensive. You also have to build a full mold and batten the thing to bring it up to the inner skin size of the boat. You then spile the diagonal layers of veneer back and forwards on the hull. With strip plank the mould stations are erected at closer intervals and the strips replace the battening so less setup time.

I'm up to my final layer of veneer now its taken me about 3 months probably about 2 1/2 hours a week (about 30 hours I think and about the same for the mold). Having said all that though I've known people who have taken years to do a hull in strip plank its about efficiencies and consistent, careful, fast and accurate work too. I found my existing woodworking skills translated easily to boatbuilding.

[JordieS]

OK thanks, and I haven't performed any of the hydrostatics as I just want to build it as a "put on display for everyone to see" model and a bit of fun.

I don't need it for my build but how do you calculate that stuff anyway? I've tried to do hydrostatics thing on Rhino but it didn't work.

Thanks

[DCockey]

I use the Hydrostatics command in Rhino and copy the results into a Excel spreadsheet.

Possible reasons why Hydrostatics isn't working:

Results are Water Plane Area = 0

• Waterline was under bottom of hull. Move Waterline up so it intersects hull at desired elevation (or move hull down).

Values returned are Wetted Surface Area = non-zero value and Water Plane Area = 0

• Symmetric=No was used with a half-hull. Change to Symmetric=Yes
• Hull has "leaks".

• Half-hull is used and the centerplane edge deviates from the centerplane. Possible ways to fix are extend the surface across the centerplane and trim at the centerplane, or rebuild the surface.

• Naked edges below the waterline. Use ShowEdgesto find the naked edges. Repair using JoinEdge, extend surface(s) and trim, if a trimmed edge Untrim the surface and then retrim, or rebuild the surface.