Does this picture make my chocks look too big?

[Don Case]

[iMustBeCrazy]

No real opinion, just a couple of examples:

 

 

[allanyed]

Don,  Take note of the depth as well as the length of the chocks.  How did you come up with the length of the floor and each of futtocks?  They seem to be very short or it may be that the chocks are so long.     Lacking other contemporary information such as a contract or drawing specific to your project, you could use the drawing that Craig posted as a guide.  You can also get a lot of useful information from Kroum Batchvarov's doctoral thesis on framing.    If you have problems finding and downloading it on the internet  send me your email address on a PM and I can forward the pdf  to you.    

[druxey]

Generally a 3:1 ratio is about right. The chock maximum depth is ⅔ of the molded thickness of the frame and each arm of the chock is 3 times the maximum depth. The same ratios apply to most scarph joints as well.

[Don Case]

OK, I've got the length about right. I knew mine were a little shallow but that's because I had to fair out the inside more than I thought. Part of the learning curve😕. I took the length from a drawing that Alan posted for me a while back.  Then I was looking at a few builds and their chocks looked a lot shorter, closer to a 1 or 2:1. 

I'm surprised at how strong they are. I was doing a little drum sanding on one and it caught and got flung across the room like a frisbee. It survived.

A sort of related question. When were chocks used and when were scarfs used? Just looking at them I don't see a lot of difference in strength. Were chocks used as a wood saving method?

[Don Case]

4 hours ago, allanyed said:

Don,  Take note of the depth as well as the length of the chocks.  How did you come up with the length of the floor and each of futtocks?  They seem to be very short or it may be that the chocks are so long.     Lacking other contemporary information such as a contract or drawing specific to your project, you could use the drawing that Craig posted as a guide.  You can also get a lot of useful information from Kroum Batchvarov's doctoral thesis on framing.    If you have problems finding and downloading it on the internet  send me your email address on a PM and I can forward the pdf  to you.    

To get the length of the pieces I just looked at the grain compared to the amount of bend. I may have been too cautious. I managed to download Batchvarov's thesis. Thanks

[allanyed]

Don,

The grain is important but keep in mind there are only several pieces for each frame.  One has a floor, second futtock on each side, and fourth futtock and/or top timber on each side depending on the size of the ship.   Look at the drawing below which was posted earlier in response to another question you had to get an idea.  These are from a 50 gun ship of 1695, but will give you an idea on the size of each piece.   In the case of the first futtocks, the contract for this ship stated that the futtocks should reach to 20 inches from the keel and each to be 12 feet to the where they meet the respective third futtocks.   The floors would be even longer.  

 

Druxey gave you the information you need for the size of the chocks themselves.

 

Use of chocks versus scarphs, depends in part on when the ship was built.   For Discovery, chocks would be likely for each joint, except,  possibly, for the top timbers which may have been scarphed to the futtock below.   Hopefully others will have more definitive contemporary information.   Goodwin shows only scarphs for 1650 to 1710 in The Construction and Fitting of English Man of War, page 14, then chocks (and scarph at the top timber) from 1710 to 1811.  In The Restoration Warship, page 44, Endsor shows  chocks being used based on The Bends of a Ship by Thomas Gagge, c. 1680.

 

Goodwin goes on to explain that things changed with the Seppings system about 1811 but this is far past Resolution so no need to get into it here.  

 

Cheers

 

[druxey]

Note to Alan as well: on smaller vessels where contemporary framing plans exist, I've seen nearly all with chocked toptimbers, but there is the occasional scarph indcated.

[Don Case]

Well, I think I'm going to finish them all like this otherwise it will look more like a dog's breakfast than it already does. I will probably plank the whole thing anyway. I don't think I would have gained any of this knowledge without just diving in. Wouldn't have known what questions to bother you with🙂

[iMustBeCrazy]

3 hours ago, druxey said:

Note to Alan as well: on smaller vessels where contemporary framing plans exist, I've seen nearly all with chocked toptimbers, but there is the occasional scarph indcated.

druxey, probably smaller than you're thinking but all(?) the frame drawings I've seen for revenue cutters and similar sized vessels (mostly 1800s) carry text such as "The timbers are to have square heads and heels coaked together as represented at 'A'; but where a square head and heel cannot be formed they are to be scarfed as represented at 'B'."

 

None show chocked joints.

 

NB: Coaked - joined with a round or square dowel.

[allanyed]

Craig, you are correct for most of the 19th century as a lot changed when the Seppings system came into use common use about 1820 based on what I read in Goodwin, page 18.    "The use of scarphs or anchor pieces was done away with, and the joints were made by means of dowels pinning both butts of the futtocks together " which seems to be as you describe,  but not until about 1820.   

 

[druxey]

Thank you, Craig. However, we are referencing pre-1800 building practice.

[iMustBeCrazy]

34 minutes ago, allanyed said:

the Seppings system came into use common use about 1820 based on what I read in Goodwin

Probably a little earlier from what I see, ZAZ6163 (Transit 1809) seems a little confused but is still scarphs and maybe chocks while on ZAZ6446 (Quail 1816) it seems firmly established. So perhaps somewhere between those dates.

But 'about 1820' still fits.