Thread: building the Heidi.

I'd have thunk radiata too knotty, coarse growth rings & patchy quality to be a serious contender.
Meranti would be more even textured, but heavy.
Might be worth having a chat with Whitewood about Pawlonia, although that might be too soft.
Hoop pine might also be worth a look, but you'd probably have to import it from Qld.
12mm plywood for the sides, hide the sheet edges, and plank the bottom in real wood ?

I'd be inclined to make the whole hull from plywood, which is immensely more stable for lapstrake builds. Meranti is a good choice, though heavier than a lot of the softwoods, not too bad really. I'll suggest a 20% increase in weight over typical softwoods in your area, which is manageable on a Heidi.

The plans show a plywood bottom and solid wood strakes, riveted along the laps with nails and screws used elsewhere.

Originally Posted by PAR

I'd be inclined to make the whole hull from plywood, which is immensely more stable for lapstrake builds. Meranti is a good choice, though heavier than a lot of the softwoods, not too bad really. I'll suggest a 20% increase in weight over typical softwoods in your area, which is manageable on a Heidi.

The plans show a plywood bottom and solid wood strakes, riveted along the laps with nails and screws used elsewhere.

I have yet to buy the plans/book.So at the moment i'm pretty much in the dark.I do like the idea of using marine ply for the strakes tho.makes a lot of sense.

Ok,The Heidi plans came the other day.Looks a fun build.Plan calls for half inch thick softwood strakes,either,cedar,spruce or white pine(what ever that is)mahogany/oak for other bits.If i use marine ply for the planking,could i get away with thinner/lighter ply?Still toying with the idea of solid timber planks and ply floor.Can i use tassie oak for the hardwood parts? With solid timber i'm to check if the sawn planks are either flat or vertical grained.Depending on species,to prevent "cupping".ply is starting to look good.

Kauri used to be used for boat building I think.
tolerates water well.

I could be wrong and it would be exxy

Typically you use the same dimension plywood as the thickness called for in solid lumber, for lapstrake. This is because plywood hasn't as much longitudinal stiffness as solid lumber, though is considerably better across the grain.

The reason I suggest plywood planking is, it's easier to get good results then with solid wood planking. This is because the solid wood strakes will need to be quarter sawn or vertical cut stock (the most costly) and predominately clear (read even more costly). Because plywood is essentially an engineered product (laminated wood), it's mass produced and thus cheaper. It's also more readily available and isn't going to cup.

but solid wood is soo much prettier.
and makes you feel like you have built something lasting.

Solid wood is only prettier is it's varnished. If you want the same look with a much more stable planking (plywood), then use a quality plywood, which finishes just as well as solid stock.

Originally Posted by astrid

but solid wood is soo much prettier.
and makes you feel like you have built something lasting.

If it's clinker and solid wood, and if you store it out of the water most of the time, it will give you a wonderful feeling that you have built something that leaks like a sieve every time you launch it. Traditional clinker really needs to be afloat all the time, or at least very frequently, so the planking doesn't open up. If the boat is going to be owned by a typical suburbanite who will only use it on weekends, plywood makes a lot more sense.

The designer does state that,if you are not keeping her in the water,then he recommends the plywood floor.I am painting the exterior,white and varnish/poly the insides. The boat will not get a lot of use.I will use half inch marine ply ripped into planks.On the outside,no one will know its ply. On the inside? I think i'll get away with it.See,this is what happens when you go to the Goolwa wooden boat fest.The wife asks why yet another boat? We have three already.The ts16 is our family play thing.The canoe for the quiet rivers and lakes,Heidi, for a quiet row on the Yarra.Or a single handed sail.Horses for courses.Ca never have too many boats.I'll keep you all informed when i start the build.Thanks for the input.

Half inch? Is the thing 30 feet long? For a basic rowing skiff, 1/4 inch is more than adequate and will give a very solid and durable structure. It will also be a lot cheaper, and easier to handle.

Plans call for half inch cedar,white pine,or spruce.i'm a little concerned that using half inch marine ply is going to make the boat rather heavy.I'll do the bottom in ply but i will do more research regarding the planks.

Half inch cedar planks are called for in the plans, because you really can't trust solid cedar planking that's cut thinner.

A 1/2" plywood bottom makes a lot of sense, considering the shape of the boat, though 1/2" plywood strakes will be heavy, much heavier than cedar.

If it was me, I'd make the lowest strake (garboard) 3/8" (9 mm) and the upper two strakes from 1/4" (6). This will make a stout hull.

With this set of scantlings, you could toss out 3 or 4 of her seven frames without concern, assuming the laps are epoxied, rather then fastened. With her seats and other athwart elements, she'll be stiff enough and light too.

I'd also tape the outside seams on the lowest strake, where it meets the bottom planking, plus an inside fillet and a layer of tape. This will make the bottom portion of the boat, a water tight box and greatly improve rigidity. The rest of the planking would be glued seams, with enough frames to help support seating. The seating could just land on cleats, glued to the planking, instead of frames, which is lighter and easier to clean too.

Thank you PAR.My thoughts exactly.Half inch ply is very heavy.The plans do call for taping the bottom to garboards.I will be keeping the frames and rivetting the planks,using a flexible caulking between.I made my pirogue using 9mm bottom and 6mm sides and it is plenty strong enough.Thanks again for your input.