Converting Carvel to Strip Plank

[potomac]

The Joel White Catspaw Dinghy plans (his take on the Herreshoff Columbia Dinghy) which are quite detailed, by the way, are for Carvel construction. I'd like to explore building this boat in strip plank. Is this as simple as substituting the planking for glued strips or is it way more complicated? I am not intending to fiberglass inside and out, just epoxy and a layer of Dynel or Xynole for abrasion resistance so I assumed the framing would remain the same. Original planking calls for 1/2'' cedar. I would probably use Douglas Fir. Thanks- Aaron

[WI-Tom]

Aaron,

my strip-planked 18-footer is built the way you suggest, using 1/2" x 1" strips, edgenailed and glued, along with seven laminated frames. I think the biggest difference between carvel and strip plank would be figuring out how many frames you'd need. I'd guess fewer than the carvel version, but that's as precise as my meager knowledge takes me.

Other than that I doubt there'd be any differences. Any shape you can plank in carvel should only get easier in that kind of traditional strip planking.

Tom

[wizbang 13]

half inch cedar is a very light boat. more like a stout canoe.
strip planking is better for a heavy vessel. in displacement and construction.
so, I might tend to build it canoe style, glassed in n out with no frames. no vertical nails.

bigger boat? different answer.

[samclem]

You'll need to account for the fact the boat is lighter built this way (Especially if you leave out the frames), You'll need to do some calculations to make sure the LWL/DWL stay the same or it may float/handle wierd. You'll need some of the frames as if i recall they help to support the floor boards, the centerboard, etc.

[potomac]

Bruce- I intended to use this as a bit of an education before taking on a bigger build (also originally Carvel, but I want to do strip plank). White has a catboat intended for cold-molding, 15' long and almost a 7' beam displacing 1300 lbs.. I think a couple have been built strip planked- at least their build photos don't show the post-strip veneers going up. Would this be more suited? If not, any ideas?

Tom- What did you build?

Thanks all- Aaron

[WI-Tom]

strip planking is better for a heavy vessel. in displacement and construction.

I'm curious why you think so? The plans for my boat (Don Kurylko's Alaska design, an 18-foot whitehall type ketch) call for exactly that: 1/2" strips without glassing both sides. The people who have built it seem to do just fine.

But yes, I hadn't thought about making sure the DWL lines up with the lighter construction...

Tom

[WI-Tom]

Tom- What did you build?

This boat: http://www.dhkurylko-yachtdesign.com/build.htm

Which is at this stage of construction right now:



Tom

[woodpile]

Joel White's design of the Jerricho Bay Lobster Skiff which Tom Hill re- designed from carvel to strip, see WB 201, is a nice example of the topic though it is glassed inside and out. If you want to eliminate the glass the best examples that come to mind are Dick Nichols West Point Skiffs and Dick Pulsifers Hamptons, related boats with proven lineage.

[wizbang 13]

well crikey, that alaska looks fine! It's 18' long, but it's a skinny light duty boat. a stout canoe.well, ok, 300 pounds is a big big canoe.
I just don't THINK of strip planking in half inch thick. Is she vertically fastened?
lemme think s'more I guess.
I would not bother to re calculate anything . If the boat is 50 or even a hundred pounds lighter or heavier, you wanna redesign the whole boat? I guess some would, but we are talking about a 3 or 4 knot boat here, not a missile.Especially a little lighter, a sandbag is simpler than a re calculation.DWL is just a line on the mold or lofting floor.

[potomac]

Tom- That boat looks great. I thought of the Alaska as being a great starting point for me as she is actually designed for a strip build. My only hesitation was her sail plan. I guess it's a ketch rig- I'm honestly not proficient enough in my terminology. That mizzen mast seems so far forward that it looked like it might be right in the way of the person on the rudder- like things could get crowded. I go pretty much everywhere with a four year old who keeps growing and if a boat's involved, you can't keep my girlfriend away so I can't think too much about solo-sailing. Then again, I don't know a thing about sailing a ketch and my worries may be completely unfounded. How have you found building her thus far?

[James McMullen]

Some people are more tolerant of the ketch's mizzen being completely, totally and utterly in the way than others of us. But that's a differ topic.

As far as the original question goes, yes you can build that same basic hull shape in a variety of ways. The original carvel version is probably most suited to those who are considering building a more substantial carvel boat down the road and wanted some practice. It is going to be heavier and probably be a little more finicky in maintenance than any of these other styles. If you wanted to build one in cedar-strip canoe style, I would buy the plans for the Cosine Wherry and follow their instructions for scantlings and glass schedule, just substituting the Catspaw stations molds. If you wanted to build strip-planking style, the follow the scantlings and techniques in Kurylko's Alaska plans.
But I think that this particular hull only really comes into its full potential for beauty when built lapstrake. It can be built epoxy-glued plywood lap, or absolutely traditional copper-fastened cedar on oak like this one that I built:





Personally, I find either lapstrake boatbuilding process to be very much more pleasant and entertaining for me than any of those other styles. To start with, you cut down the need for sanding and longboarding by well over 90%.

[Rich Jones]

I built my 20' Stadel pilot sloop more than 20 years ago and strip-planked it. George Stadel Jr. designed it for carvel planking in 1940. When I visited with him in 1989 (I think he was in his 90's), he said that strip planking would be just fine. Said to skip every other rib. All the other white oak framing remained the same. It was still sailing as of 2006, then I lost track of her.

At the time, I was also going to build the Catspaw as a learning project before going on to the larger boat. But, Mr. Stadel said to just go with the big one as it's the same type of construction and any minute imperfections would be covered up by the interior ceiling planks! So, I did just that. I had the Catspaw building molds in my basement for the next 20 years before throwing them out. By that time, I was attracted to other designs.

And, curses to that James McMullen fellow!! He makes the rest of us look like wood-butchers!!

[WI-Tom]

That mizzen mast seems so far forward that it looked like it might be right in the way of the person on the rudder- like things could get crowded.

Don Kurylko, the designer, cleverly accounted for that by making the boat so narrow that most of the time I'll probably be sailing it with the mizzen alone, stepped in the center mast position anyway!

But I sailed a couple of Jim Michalak's Laguna design (also ketch rigged) and, as James McMullen suggested, found that I have a pretty high tolerance for a mizzen right in front of the helm. It LOOKS cramped, but in practice I found it fine. And the Alaska has quite a bit more room behind the mizzen than a Laguna. And don't forget the Alaska has a couple of more cockpits further forward, so no one but the helmsman needs to fit behind the mizzen.

How have you found building her thus far?

Best advertisement for glued lap constrution I can imagine.

I thought strip planking was the way to go because it's easy to get a round hull, and it's forgiving to beginners. True enough. But my brother started his lapstrake boat a year and a half after I started, and finished a year and a half before I will (I hope). And after watching him, I agree that glued lap is no more complicated--and a heck of a lot less tedious, and more pleasant--than strip planking. But I'll have a beautiful boat in the end so that's a minor complaint at this point. But if there's a build in my future, it will be glued lap.

Tom

[WI-Tom]

well crikey, that alaska looks fine! It's 18' long, but it's a skinny light duty boat. a stout canoe.well, ok, 300 pounds is a big big canoe.
I just don't THINK of strip planking in half inch thick. Is she vertically fastened?

Yep, I've built a few canoes and the Alaska doesn't seem much bigger, that's for sure.

The plans suggest pre-drilling holes for 1/8" dowels for vertical fasteners. I was not neat or organized to make that work and quickly shifted to edge-nailing the planks every 8" or so instead--not that I measured. Seemed to work fine.

Tom

[potomac]

Thanks Tom. I think a lot of my interest in strip-plank actually comes from Bruce's 34' Venus build. I have it in my mind that I've got maybe three big building projects left in me given my age and the free time I have: A cottage on the beach with a workshop on the ground floor, a little mountain cabin, and maybe a cruising sailboat. I'd be doing most of those projects pretty much myself and Bruce's build convinced me that one man could build a big boat using strip planking. I love lapstrake- traditional and glued-ply. I think it is the prettiest type of boat construction out there (although those stripper canoes are awfully pretty too), but even the largest lapstrake designs I've seen are really shallower draft sharpie type hulls, and I'm becoming convinced that while sharpies are probably ideal for my local waters, they are not ideal for cruising the caribbean. Those big, deep, heavy boats that are better suited to Caribbean cruising seem to be Carvel, strip, or cold-molded. Bruce's use of Woodwind strikes me as practical, no-nonsense, and with more freedom and flexibility than a Carvel boat (and I have no idea how I'd pick up those big ole' planks- no matter how many push-ups I do). I'm not sure why I'm not considering cold-molded- I guess it just seems sort of endless. If I ever decide to just sail and not build a great big boat and, Heaven forfend, purchase something plastic, then I guess it'll be a whole catalogue of Iain Oughtreds- from the Acorn 15 to the Eun Na Mara and a not so pretty, but still floaty sister to James' beloved Rowan.

[WI-Tom]

Hey, if you like big strip-planked cruising boats (and so do I!), I hope you've seen Don Kurylko's thread on his 34-footer, which he built (I'm assuming) mostly alone. Don's a meticulous builder who really makes strip planking work. It's a great thread for anyone contemplating a big build.

http://forum.woodenboat.com/showthre...lko-s-new-boat

Tom

[potomac]

A bit intimidating Tom. I'm off to Craigslist for a plastic boat and the Woodenboat store for some plans- better make it something I can build from a kit.