Thread: 9' 6" Nutshell Pram- Ply inquiry

Howdy,

Ply through most of the world is 8ft x 4ft (2400 x 1220), it is very unlikely that you will find 10ft sheets.

The hoop ply is very good quality in exterior and marine grades, however is only available in Australia smaller than 8ft x 4ft sheets - 2400 x 1200 size so you have to make sure the boat will fit on the sheets.

Australia is about the only country in the world that has the 2400 x 1200 plywood - so you have to make sure the boat will fit if using that size.

Most people will use some sort of joint to make the ply to the length you need.

Butt straps are just a ply doubler that bridges the join. It is normally 20 times the ply thickness.
Scarf joins are two slopes planed on the edge of the ply which are then glued together - the normal guideline for the slope is 6:1.

If using butt straps to join the bilge panel to length (the side panel and bottom panels are not very twisted) it is best to put them in the back end of the boat otherwise you will get a flat spot in the highly bent forward part.

If they panels won't fit on the Hoop Pine you will have to buy an imported ply.

There is another option too of using Gaboon ply which is about 2/3 the weight of regular plywood but more expensive then most - can be quite nice when carrying the boat around.

One area where the sailing version of the Nutshell can be greatly improved is to increase the length of the centreboard - it is very small - quite undersized and adding 200mm or so to the bottom will make the boat sail much better.

Best wishes
Michael Storer

Best wishes

Hello Michael,
Many thanks for the reply, greatly appreciated. Yes I suspected I would have ply size problems and now I am a concerned with the idea of joining sheets to form the Nutshell Pram. I guess it sounds simple enough but I do have concerns about how sound the finish and performance will be. I still feel the 7'6" version will be a little tight 'comfort wise' for another person. I am now revising the idea but still think the Nutshell is a great little boat. I have just visited your site and am really impressed with your range. Actually like the canoes believe it or not. The Pram was only to be used in the reasonably safe and protected waters of Westernport Bay here in Victoria. Just wanted something seaworthy, easy for a novice with the potential to sail, be transported without trailer and able to comfortably carry one other or two smaller ones at a pinch. The tip about the Gaboon ply is useful as the boat will have to be carried a little way to the waters edge. Thank you also for the comment on the dagger board length, that is one very helpful piece of information. Best wishes, John (Still pondering choice)

Originally Posted by melbournehouse

Hello to everyone and thanks for the opportunity to join and post. Well after months, if not years of reading boat forums I have decided on a dinghy!. I believe the Joel White Nutshell pram may serve all the requirements and be easier enough for a first time dinghy builder. Although I need some advice on ply if someone can assist. I am used to the standard 2400 x 1200 size but this dinghy calls for 10' sheets (if you choose the 9' 6" larger model). The little book on the boat suggests it be constructed from marine grade Honduras Mahogany in various thicknesses of 3/8 , 1/4 and 3/4" ply. Obviously good quality is worth it but Mahogony? This booklet is a few years old now and I'm sure someone can suggest something equal or better for modern day Australian conditions. I would prefer to purchase environmentally sound ply products and have had experience with Aussie Hoop pine but not exterior or marine grade. Yes, I can see the irony of environmentally sound timber covered in epoxy!. Has anyone build a Nutshell pram? and could someone advise on larger 10' size sheets. Are they readily available? All suggestions welcome, the 10' sheets sound expensive and I may have to downgrade to a 7' 6" if they are too pricey or difficult to obtain. Thank you everyone, John

Depending on the supplier you can get Gaboon Marine Plywood to BS1088 in 2500x1220, or alternately you can get S/BB grade Birch Plywood with an A Bond glueline in 1525x3050 sheet sizing. I state it in that size as it is a cross grain product. Not the cheapest on the market but a very impressive plywood. And there are also some other Plywoods around imported out of SE Asia in mixed hardwood species that have a WBP glueline in 3050x1220. But that vast majority are either 2400x1200 (Aussie Made) or 2440x1220 (Imported)

Uckillya,

Many thanks, thought there must be some weird and wonderful sizes out there. Now I just have to decide. Join basic size sheets, pay the price for larger quality stuff or even decide on another design. Will let everyone know. John

The little Nutshell is a bit cramped for two adults sailing, though this is the best size as a tender for a larger boat.

The bigger one is much better for two person sailing.

David at Duckflat has a little one he uses for fishing off the shore. He can launch his boat and be out far enough to drop a line before the bigger boats have found a place to park the empty trailer.
Best wishes, MIK.