Determining width of hull planks

[Daedalus21]

How do you determine how wide a plank is at each frame? Is there a way other than using proportional dividers?

 

[Rob444]

Many people use tick strips and divide the distance of the bulkhead by the number of plans to get how wide each plank should be.

This video may be of help

Rob

 

[AllanKP69]

The video is a great tool. Also, the attached paper by David Antscherl will help. There was a post here at SoS not too long ago on making tick strips, maybe you can find it with a search. If nothing else take a string and lay it along a frame at the dead flat from the rabbet to the top of the top timber. Then straighten and measure the total length. Assuming planks are about 10-11 inches broad, divide the number of strakes needed. This number of strakes will be the same from stem to post barring the need of a drop strake or stealer. Then it is just a matter of dividing the frames every few stations by that number of strakes to make the tick strips. There is no need to make one for every frame but too many is better than not enough.
Allan

 

[polydoc]

I find that dividing the hull into planking bands of about 4 planks each works well. Starting at the deck or wale, measure the perimeter of the widest bulkhead down to the keel. If your plank width is say 4mm, mark down the bulkhead in increments of 16 mm. Lay a flexible tick strip through the first mark into a fair curve from bow to stern and mark where it crosses each bulkhead. Check to make sure at the bow the planks will not have to taper to less the 50% of the width. Repeat this process down the hull. For each planking band, measure the perimeter between marks on the bulkheads, divide by four and taper the planks accordingly. Planking should be pre-bent to shape for the best results. I wet the planks and bend them over the barrel of a soldering iron. Planking above deck normally goes very easily since little to no plank taper is usually required.

 

[AllanKP69]

Planking should be pre-bent to shape for the best results. I wet the planks and bend them over the barrel of a soldering iron.

Do you do this just for bending with the breadth or also for edge bending so there is no lift to the planks on the hull?
Allan

 

[Bob Ellis]

How do you determine how wide a plank is at each frame? Is there a way other than using proportional dividers?

You can make this complicated or simplify the process. The easiest is measure up the deepest bulkhead and divide by the nomber of 5mm (?) planks it will take from keel to wale, say 20 planks. That same twenty planks will need to fit at each bulhead and the stem. Measure the length of each bulkhead and divide by your twenty planks. Mark the plank width with a sharp pencil dot...next bulkhead etc...Your dots should of course be at the bulhead distances lengthwise along the plank. You don't need to measure at the stem, when you have joined the dots to get a taper line the taper will extend beyond b'hd 1 to the stem. Planks will need pre bending. They bend downwards so the upper edge of the plank is tapered. If you're building with a 2mm inner and veneer outer (always walnut!) The veneer won't bend, the walnut will splinter. You can get fresh timber, do a 1.5 inner and 1mm outer (Caldercraft and Amati come with these timbers) And get something better that the ubiquitous walnut!! At least cherry!

 

[polydoc]

Do you do this just for bending with the breadth or also for edge bending so there is no lift to the planks on the hull?
Allan

Edge bending can be done but you have to go very slowly, it takes a lot of time, and only works (for me anyway) with some woods. With my usual practice of using 1/16" bass for 1st planking and 1/32" cherry for 2nd planking the planking follows the upward curvatures at the hull ends without the need for prebending.

 

[AllanKP69]

Edge bending can be done but you have to go very slowly, it takes a lot of time, and only works (for me anyway) with some woods. With my usual practice of using 1/16" bass for 1st planking and 1/32" cherry for 2nd planking the planking follows the upward curvatures at the hull ends without the need for prebending.

I had no problem with hardwoods like Castello, Europeon boxwood and holly so far. I soak it overnight then it bends with the jig fixture in a few seconds. Hot air gun dries it in a minute or two so there is no lift. This has been posted here at SoS in the past, but just in case, for anyone interested in doing planking that looks like it is on an actual ship, the following four part by Passaro explains how to properly plank a hull. It is not difficult even with hard woods. I changed from a hot iron to a hot air gun and it works even better.

Allan

 

[Bob Ellis]

Edge bending can be done but you have to go very slowly, it takes a lot of time, and only works (for me anyway) with some woods. With my usual practice of using 1/16" bass for 1st planking and 1/32" cherry for 2nd planking the planking follows the upward curvatures at the hull ends without the need for prebending.

The planks curve downwards at the stem. Look along the planks from the stern to see the direction. If you try to plank straight at the belly of the hull where there is the greater curvature the planks will buckle. Also see Chuck Passaro's videos 'Planking the Winchelsea'
This is why we taper the top edge making one side longer. See 'How to bend deck planks' by Olha Batchvarov, the same philosphy applies to hull planks.
As you say some timbers are harder to edge bend, and some impossible. Walnut veneer will splinter, basswood isn't good. Cherry at the very least, pear is better.
Most people use home made jigs to edge bend.

Edge bending can be done but you have to go very slowly, it takes a lot of time, and only works (for me anyway) with some woods. With my usual practice of using 1/16" bass for 1st planking and 1/32" cherry for 2nd planking the planking follows the upward curvatures at the hull ends without the need for prebending.

In case you haven't seen Chuck's video Alan has posted a link.

 

[AllanKP69]

The planks curve downwards at the stem

Exactly. Before being glued onto the framing they definitely curve downwards as they approach the stem and upwards at the sternpost. When they are attached to the framing they will then curve upward at the stem and sternpost. Also, the garboard should end at the boxing joint rather than carrying forward too far, this is critical. Planking expansion drawings show this clearly. They also show how the planks are about half the breadth at the stem compared to the dead flat area and the lower half of the strakes are wider at the post. No strakes of planking are straight before they are secured to the hull nor after. Lastly, the wales need to taper in thickness at the stem so they seat in the rabbet rather than standing proud of the other planking like they do farther aft.
Allan






Contemporary model at Preble Hall.

 

[polydoc]

I had no problem with hardwoods like Castello, Europeon boxwood and holly so far. I soak it overnight then it bends with the jig fixture in a few seconds. Hot air gun dries it in a minute or two so there is no lift. This has been posted here at SoS in the past, but just in case, for anyone interested in doing planking that looks like it is on an actual ship, the following four part by Passaro explains how to properly plank a hull. It is not difficult even with hard woods. I changed from a hot iron to a hot air gun and it works even better.

Allan

Thanks for posting these Passaro videos. They were excellent. I noted that he was single planking with rather wide 1/4" planks so getting them to lay perfectly flat was essential. My experience is with narrower planks, usually 1/8" to 3/16" and I have not had to edge bend. When double planking at these widths, where the edge of the first planking lies above the desired hull surface at the bow it is just sanded smooth. For the 1/32" second planking I use CA glue at the bow and press it down to get a flush fit.