Why second hull plank?

[bigcreekdad]

I'm working on the Cheerful, which calls for single hull planking. Yet, many kits call for second planking, which I have done. What are the pros and cons?

[bruce d]

Hi, I asked pretty much the same question a while back:

Perhaps it will help? It certainly was useful to me hearing from people who had tried both and got rid of some of my misconceptions.

 

Bruce

[Gregory]

Basically , with double planking. the first layer lets you make mistakes that you can sort out and create a smooth basis for the finishing layer.

 

Up until recently. most of the kits aimed at beginners had too few bulkheads to get a good basis for a successful single planking.

Kit makers had to keep costs down, which means less material.  

 

For the most part, double layer planking became a convention based on the majority of kits kits that were available.

People would buy the kits and try to follow the instructions, that called for double planking.

 

Single planking has only become a reasonable option with the growth of sites like this, where people can actually learn how to do it.

 

At this stage in my model building, I prefer double planking because I can use a variety of veneers that wouldn't be available as strip wood for a single planking effort....

 

 

Bruce,

From your  link, I really like these comments by Kurt.

 

Quote

 

Double planking is done to provide a fair base for the final planking - usually because the bulkheads are widely spaced and the planks stretching between the bulkheads tend to flatten out rather than keeping the fair curve that closely spaced bulkheads would provide.  The area that are not fair can be sanded down or filler added as needed to provide the fair surface.  Same as planking a solid carved hull.

If your bulkheads are close together double planking isn't needed.

 

 There is a lot of good information in that topic..

Edited October 14, 2019 by Gregory

[Chuck]

Double planked hulls usually dont have a rabbet.  That is problematic.   Double planked hulls as said were done because the MFG usually cheaped out on the number of bulkheads.....

 

If your kit has few bulkheads and is single planked that would be a huge problem....

 

If you have a lot of bulkheads or frames......Why would you plank twice if you take your time and do it right the first time.

 

If your hull is painted or plated,  why plank it twice?

 

If it is not and you dont know how to plank,  then it doesnt matter if you you plank the first layer poorly because chances are that the second layer will also be poor.

 

Best to plank it once and plank it correctly.   Single planked hulls force folks to learn proper planking techniques as well.

 

My advice would be to start a log and post some photos.....also ask a lot of questions.  Its not easy to plank a hull and it requires some practice.   With lots of failures along the way.  

[tlevine]

And if you are interested in learning how to plank correctly, consider this:

 

[Gregory]

11 minutes ago, SpyGlass said:

But Cheerful is a lovely build  and Chuck gives excellent guidance -  lets see your log

Great post!

  If we could all build like Chuck, Chuck wouldn't be so special!😄

[Dr PR]

I have never built a double planked hull, so I do not speak from experience. But it is pretty obvious that the purpose of the inner planking is to create a smooth curved surface to serve as a base for the outer planking. It doesn't matter what material you use (it doesn't have to be wood) or how neat the inner planking is, and you can use as much putty as necessary to fill low spots to get a smooth curved hull surface.

 

You can accomplish the same thing by filling between bulkheads with balsa or foam and then sanding it to smooth curves.

 

Then the outer planking can be very thin material that is easy to cut and will twist and bend easily to fit the curves of the hull.

 

I have built kits that had bulkheads too far apart. If the bulkheads are two inches (4 centimeters) or more apart the planks will make flats between the bulkheads and the hull will not look good! But I have added additional bulkheads - cut from model aircraft plywood - to fill the gaps. I like the bulkheads to be about an inch, or two centimeters, apart or less. The natural "springiness" of the wood will produce smooth curves between the bulkheads.

 

****

 

Someday I may build a model with a double planked hull - a wooden minesweeper. These were built double planked. But the inner planks were placed at a 45 degree angle to the frames. The inner planks started at the keel and angled up to the bulwarks. Then the outer planking was added parallel (more or less) to the waterline. This produced a much stronger hull structure, and that was good for a small ship that might be in close proximity to a detonated mine that was large enough to sink a battleship!