what is a tollerable hull twist amount?

My kayak is on its cradle forms.  all stitched up.  It looks true and fair however I think there might be literally 1cm of twist. Is this being too precise or is itconcidered a lot? Should I worry?I also used a lateral level (bubble level) and crossed it over the sheer line of the hull in multiple places.  It shows its all level from the bow to the stern but by the time Im checking the stern that is where I must lift one edge of the ruler about 8mm to make it level.  In my mind I don't think the water I will be floating on will notice.  This isn't a rocket ship.  I'm sure even the rocket ship has tollerences greater than 8mm.  Right?

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RE: what is a tollerable hull twist amount?

well....its not so much the 8 mm lift but the 8mm over what distance....and optically how it is going to look.

8 mm is a little over a 1/4 inch....which in my book is a relatively a large deviation....especially at an end.  i would loosen some of the stitches and straighten it out.   at this point your 'fix' is free.  every fix after this -- once glue is applied -- gets expensive.

deviations tend to build on one another and get progressively harder to hide/manage. so get the initial hull set-up right.  you will be happier as a result.  it will only cost you another 15 to 30 minutes to sort out.


RE: what is a tollerable hull twist amount?

I think the 8mm "twist" is gradual from bow to stern.  When I sight down the middle using the stick method they show on the video.  They are spot on.  I am a young gentlemans and I know I have a very good eyesight for things to be crooked.  So just looking at the kayak it looks very, very straight.   

RE: what is a tollerable hull twist amount?

I also have a string line tide to the tip of the bow wedged between the two plywood halves down to the stern.  I sight that down any direction even down the keel line and it looks straighter than an arrow.  The bow and stern both have an upswing (Night Heron) and that line also lines up well with the tight string.  So I am not sure where the error truly is.  Maybe its just the port and starboard "sides" are not flush with each other.  ( I hope that makes sense)   

RE: what is a tollerable hull twist amount?

   All things being equal.......and they may not be......8mm twist is nothing if you never paddle any distance. A twist will "trim" the boat to make a turn. It's bad enough to counter a current, tide, wind driven turn much less fight boat induced trim.

Check the clamps with the levels as shown in the manual. Once the boat is centered, level fore/aft and level side to side and fixed to the supports I  rig a reference line (string) line along the center line fore and aft. From that reference line I check "plumb" of the joints at the ends. They should be straight up and down (plumb).  Note too that at the same datum point the shear clamps should be equal distant fromt he reference line too.


It won't cost anything to try and re-tension the wires to get the shape right.

RE: what is a tollerable hull twist amount?

Thank you all.  I went back to my kayak hull and measured everything out.  I seem to have mistaken theamount.  It is more like 2mm not 8.  However I want it to be perfect.  I will utilize the tips and advice from all above.  Thanks you all of you I will have a fair and true kayak   

RE: what is a tollerable hull twist amount?

PS for Grumpy....My manual doesn't show or explain anything about twist as you mentioned to refer to.  just FYI.   

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