Planking, bevelling and screwing

Late Oct:  well, after a layoff period to recover from a back sprain (blunt planes and lower back injuries do not mix) I purchased myself a cordless electric plane and I'm back to planking.



- better to use as few screws as possible to hold it together in the dry fit - after all, it is the epoxy that will be holding it together not the screws
- i bought brass screws, but silicon bronze screws would have been much cooler, especially since you don't need so many anyway (or at least, I don't think you do - I don't actually know where all those hundreds of screws are meant to go without the book!)

-

Don't add a dozen screws like I did!

the bevelling is reasonably important to ensure the planks sit nicely against each other, dont be in too much of a hurry with the plane - I've been planing off fractions of a mm, then checking to see how it looks.

The bevel angle will allow the next plank to sit ~ flush. Epoxy will make up the difference.

First off I would say I've learnt a few things in the last few weeks:
- the accuracy of the laminated rib and temporary plywood moulds is really important
- the planks are shaped assuming the moulds are accurate, so lay them against the drawings, and trim and/or add until they ARE accurate
- I pulled my dry fit planking apart, pulled off the moulds, and started trimming once I saw where being sloppy was going to lead me

I'm going to have a lot of screw holes to putty up when I finish!

holding down roughly with clamps, tapping into place then using a countersink bit, an 8G by 25mm brass screw and an impact driver seemed to work pretty well, even without any help!

While recuperating, I made some short 'saw horses' - I would be ashamed to admit it took me three goes to get this right on any other forum!

Showing the shape of the 'boat' with the three planks fitted on one side.

Showing the fit of the planks to the laminated rib, on the inside, once I had spent 2-3 hours pulling it all apart and planing the rib down to proper, accurate size (actually it is only accurate on the outside, it is actually more skinny than the original, but the inside curve doesn't matter.

Oct 2014:
As Ive got to the point of placing and fixing the plywood bottom and sides to the temporary frame, I realised that I really should have bought that book that was reccomended on Amazon..."How to build the Nutshell pram" !  I have no idea how all the screws and bits of wood fit together . I had naively assumed the paper plans would have all that.

Back down to Whitworth Marine in Caringbah with a sheet of the plans annotating all the screws I needed, provided welcome distraction for the older boatbuilders there who crowded around to have a look at what was being attempted, as well as comments from the younger guys along the lines of how much more useful the dinghy would be with a 30hp outboard affixed!!

Back to Google, 
and I must also mention here how useful other blogs have been for me, notably:
 -- Building Our Nutshell Pram by BZ on   "nutshellpram.blogspot.com.au"


and now looking at the photos on this blog to see where the screws go!
 -- Nutshell Pram Construction by Shutterfly at nutshellpramconstruction.shutterfly.com


NUTSHELL BOTTOM DRY FIT:
First off, I added bracing to the temporary moulds to take the strain of the bent plywood, and also an extra batten to straighten up the laminated mid frame.

Next was to dry fit the plywood bottom, drilling holes for the Record clamps to pull down the plywood to the moulds.

(note; remember, spade bits don't like 10G steel wood screws!...scratch one 22mm spade bit:)  

The bottom didn't seem to line up exactly with the moulds, so I added the mid plank on one side as another guide. Again, I drilled holes in the temporary moulds with a spadebit for the clamps. Not wanting to drill large holes through the stern and bow transoms, I setup an easy windlass to pull the plywood down to the bevelled transoms.

Its starting to show its final shapes, but I have a bit of adjusting to do before I screw down the ply bottom. It's been hot enough to burn outside today, so this will have to wait for more afternoon shade....