Joggled timbers

Sorry, I still don't get the sequence of operations:

1) Build a frame of some sort
2) Steam and bend over-thick timbers onto the ribands
3) Remove the ribands?
4) If not, how do you rivit the planks with the ribands in the way?
5) If yes, how do the timbers hold their shape until the planks are all secured?
6) Cut out notches, planking up from the keel

Something like that?

So can steamed frames be added later, or not? How do cut out the wedge-shapes if the timber is hard up against the planks? How do you allow for the progressive movement as the timber is gradually reduced in thickness and pressed outwards against the planks ?
 
There is an excellent picture here;

http://intheboatshed.net/?s=joggled

of the finished result.
Was the entire rib cage built first, the notches cut out, then planked?
Or were the ribs steamed into the completed shell afterwards, as in normal clinker construction?
If the latter, how were the notches cut out after the ribs had been steamed and bent into position?

As the joggled bits in the photo don't actually seem to be a very good fit against the planks anyway, what is the purpose?
 
Purpose appears to be production of a very pretty interior when brand new and ...

the creation of lots and lots of tiny spaces which cannot be subsequently cleaned or treated and that will grow mould as soon as a cover is put on.
 
I was thinking it sounds like the way the ribs in the Cornish Pilot Gigs are done, I just didn't get around to nipping to the boatshed and looking.

In the Maritime Museum at Falmouth, there is an exhibit showing the stages of construction of a Gig, and the "joggled" ribs are clearly visible.

As for why it's done that way - perhaps it gives greater strength for a given weight of timber?
 
A conclusion???

peter radclyffe said:
a joggle is usually done to give support across the face of the plank
Click to expand...

....so therefore allowing thinner planking and saving weight.


So, its a tricky and time consuming method for lightly built boats that are raced or carried.
Time to build increases build expense. I don't think it would make a hull stronger, just as strong as normal steamed timbers, but with the advantage of a possibily lighter hull.
 
cliffordpope said:
Sorry, I still don't get the sequence of operations:

1) Build a frame of some sort
2) Steam and bend over-thick timbers onto the ribands
3) Remove the ribands?
4) If not, how do you rivit the planks with the ribands in the way?
5) If yes, how do the timbers hold their shape until the planks are all secured?
6) Cut out notches, planking up from the keel

Something like that?

So can steamed frames be added later, or not? How do cut out the wedge-shapes if the timber is hard up against the planks? How do you allow for the progressive movement as the timber is gradually reduced in thickness and pressed outwards against the planks ?
Click to expand...
1) Set up your moulds
2)ditto
3)Remove ribbands as required, just like building in carvel.....
4)....just enough to give access
5)n/a
6)I think you would need to run a fairing batten around, and mark off where the top edge of the plank comes, then notch out to the standard plank thickness, then spile off for your plank, then fit n fix.
 
Keith 66 said:
Thats the way i would do it, perhaps the builders of that fine Pilot Gig could enlighten us how they did it.
Click to expand...
There are pictures of the Lyme Regis Gig being built in 2008 on the BBA web pages. There's not a lot of detail in relation to the joggled frames but it's clear how it was done. The planking was done and the moulds removed in the usual way. Oversized timbers steamed and bent to shape but not fastened, then (no pictures of the intermediate stages of this bit so - presumably - ) joggles cut to fit the planking and riveted through the lands. The timbers end up quite thin compared to the sizes to start with.
 
KenMcCulloch said:
There are pictures of the Lyme Regis Gig being built in 2008 on the BBA web pages. There's not a lot of detail in relation to the joggled frames but it's clear how it was done. The planking was done and the moulds removed in the usual way. Oversized timbers steamed and bent to shape but not fastened, then (no pictures of the intermediate stages of this bit so - presumably - ) joggles cut to fit the planking and riveted through the lands. The timbers end up quite thin compared to the sizes to start with.
Click to expand...

No.
 
Well unless the suggestion is the photographs were faked, the "no" can only apply to the bit that wasn't photographed, ie the actual cutting of the joggles.

That's the bit I find hard to imagine. It's one thing cutting shapes out of a straight bit of wood, but the trouble with a curve is that there are no fixed reference points. As you cut it and press into position the circumferential distance slowly increases, so bits that were once correct surely gradually cease to fit so well as you work along?

Ever tried cutting lino to fit round a door frame on a curved wall?
Or wallpapering the inside of a windmill?
 
cliffordpope said:
Well unless the suggestion is the photographs were faked, the "no" can only apply to the bit that wasn't photographed, ie the actual cutting of the joggles.

That's the bit I find hard to imagine. It's one thing cutting shapes out of a straight bit of wood, but the trouble with a curve is that there are no fixed reference points. As you cut it and press into position the circumferential distance slowly increases, so bits that were once correct surely gradually cease to fit so well as you work along?

Ever tried cutting lino to fit round a door frame on a curved wall?
Or wallpapering the inside of a windmill?
Click to expand...
Yes, fair enough. My point is that in the case indicated there was no question of frames being set up and cut before planking. I'm not trying to start a barney, just curious.
 
Seanick said:
1) Set up your moulds
2)ditto
3)Remove ribbands as required, just like building in carvel.....
4)....just enough to give access
5)n/a
6)I think you would need to run a fairing batten around, and mark off where the top edge of the plank comes, then notch out to the standard plank thickness, then spile off for your plank, then fit n fix.
Click to expand...

Sorry about 'no' reply. new baby, running a workshop etc etc


The 'no' was with regard to the possibility that the timbers are steamed in AFTER the planking, pre-notched.

My response....'No !'

As discussed above, steam in timbers onto ribbands, remove ribbands and plank up as you go, notching out as you plank up.

Nigh on impossible to steam in a pre-notched timber as discussed above.
 
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