Subject: Re: [baidarka] Bending ribs on Greenland
From: James Mitchell (baidarka@earthlink.net)
Date: Sun Feb 29 2004 - 18:26:39 EST
Have fun!
On Mar 1, 2004, at 8:15 AM, steveJ wrote:
> The section molds are only temporary, Made of plywood. Notched to
> receive chines and keelson.
> Since the temporary spreaders need to be placed between the gunnels,
> why hot just extend them up
> to establish the chine locations and keel profile? Then bend in the
> ribs. This would be a little more accurate to mantain the shape of the
> hull at critical points like the depth at the back of the cockpit rim
> and the water entry
> section. It would also allow the positioning of the chines to be
> worked
> out so that the skin does not touch the ribs.
>
>
> steveJ wrote:
>
>> The section molds would be removed with the method I am describing.
>> How would the flexibility be effected? The finished structure is the
>> same either way.
>>
>> James Mitchell wrote:
>>
>>
>>
>>> I have used station frames to approximate the shape of the chines,
>>> but
>>> I remove them as soon as I can. I set a couple ribs on either side,
>>> and
>>> then take them out. These hulls have much more flex than a carvel
>>> hull,
>>> and I think the frames would interfere with that.
>>>
>>> On Mar 1, 2004, at 7:27 AM, steveJ wrote:
>>>
>>>
>>>
>>>
>>>
>>>> I'm about ready to start bending some ribs on a Greenland style
>>>> kayak.
>>>> I've been using various books and information resources for
>>>> techniques
>>>> and procedures.
>>>> One thing that puzzles me is the way that the ribs are bent free
>>>> hand
>>>> to the desired
>>>> shape and then the longitudinals are lashed in and faired.
>>>> Doesn't it make more sense to set the longitudinals in place using
>>>> section molds with notches cut to
>>>> receive the keel and chines and then bend the ribs by steaming and
>>>> springing the rib to the points
>>>> established by the longitudinals? This would follow traditional
>>>> bent
>>>> frame carvel planked boatbuilding
>>>> methods and would eliminate the novice having to try to "eyeball"
>>>> the
>>>> correct shape of the rib. It would
>>>> also eliminate having to calculate the length of the rib prior to
>>>> bending. Just bend the rib roughly so it fits
>>>> between the gunnels and clamp it to the keel and chines. When dry,
>>>> mark and cut the ends by adding the depth of the mortises. Remove
>>>> the
>>>> keel and chines which are temporarily lashed in place and install
>>>> the
>>>> ribs in the usual manner. Although the bend would be a bit tighter
>>>> than the real distance between gunnels, it seems like it wouldn't
>>>> matter and the ribs would have some spring back and fit in the
>>>> mortises anyway What am I missing?
>>>> -
>>>> Baidarka Mailing List - All postings copyright the author and not
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>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>> James Mitchell
>>> Email: baidarka@earthlink.net
>>> Japan: 090-4974-3874
>>> Japan (from USA): 011-81-90-4974-3874
>>> US Message Phone: 425-424-1325
>>> -
>>> Baidarka Mailing List - All postings copyright the author and not to
>>> be
>>> reproduced outside Baidarka or Baidarka archives without author's
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>>>
>>>
>> -
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>> reproduced outside Baidarka or Baidarka archives without author's
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> -
> Baidarka Mailing List - All postings copyright the author and not to be
> reproduced outside Baidarka or Baidarka archives without author's
> permission
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>
>
James Mitchell
Email: baidarka@earthlink.net
Japan: 090-4974-3874
Japan (from USA): 011-81-90-4974-3874
US Message Phone: 425-424-1325
-
Baidarka Mailing List - All postings copyright the author and not to be
reproduced outside Baidarka or Baidarka archives without author's permission
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