Design help

[disenmann]

I'm trying to choose a design for my first stipper and am having trouble finding a plan I like. I like the looks of most "modern" style canoes with relatively short, plumb stems and fine entry lines. More often than not I will be solo, but from time to time anticipate having a companion so two seats would be necessary. I like the idea of a symmetrical hull so I can just turn it around and paddle from the bow seat when solo, instead of trying to position gear/weight to get the trim nice while paddling from the stern. For dimensions I was figuring 15'-16' with a 33"-35" beam. I wouldn't have to have a large capacity as I will be using it for casual day trips on flat water.

I have searched for many hours trying to find a plan that meets this criteria with no luck. I literally think I have seen every webite, store and blog associated with strip canoes. I did find one modern-style with a symmetrical hull but the plans are not available. I have contemplated modifying an existing design, but am a bit leary considering this is my first build.

One thought I had was to use the F17 design and turn it into a symmetrical hull. If one were to use stations #9(widest, lowest sheer) through #16(stern), this should create a fair, symmetrical hull. With 12" station spacing the canoe would be 15' in length and roughly 33" beam. Obviously the performance of this canoe would be nothing like that of the F17.

Am I overthinking this? Am I making too big of deal out of the asymmetric hull? Any advice would be appreciated.

Thanks, Dave

 

[Todd Bradshaw]

"Am I making too big of deal out of the asymmetric hull?"

Probably. Considering that about half of the Current Designs line of kayaks are Swedeform (widest waterline beam aft of center) and the other half are Fish-form (widest forward of center) it's fairly obvious that both types can work on paddled boats. Nothing horrible will happen if you turn a Swedform canoe around and run it backwards. It may not be quite as efficient, especially in shallow water, but it will still, more than likely, paddle pretty reasonably.

The reason for the shallow water thing is that in addition to throwing a wake out to the sides at the bow, boats also send one downward. If you're river tripping and happen to cruise over a shallow spot like a sand bar, you can see this in action. The downward wake hits the bottom and bounces back upward. This lifts the bow a bit and the stern squats. The boat is now out of trim and trying to climb uphill over a pillow of reflected bow wake, so it slows noticably. In addition to moving the beam aft a bit at the boat's center, many asymmetrical hulls also have more volume in their stern cross-sections. This gives the stern a bit more buoyancy (and reserve buoyancy) to help prevent the stern from squatting in shallows. It's not a bad thing to have in your boat's bag of tricks. Turn the boat around, or build it symmetrical and it will still usually paddle decently, just not as well in those situations.

If you're serious about performance though, and plan to paddle solo a lot, it's probably worth thinking about a third seat, thwart or paddling station (even if it's removable). The bow seat of a backwards canoe works, but it's almost always a bit too far from center to really be efficient. Turning the boat around to it's proper heading and being more centered is always going to perform best.

Boat design wise, I'd be leaning toward the Freedom 15 from Bear Mountain, maybe the 16' or Micmac from David Hazen (you can add the stern volume if desired, or leave it out, and the stem shape is pretty easy to modify if desired). If I could find the lines for something very close to the 16.5' Mad River Malacite, it would probably be ideal for that sometimes-one-sometimes-two-person range, which is kind of a hard gap to fill. It takes about 31"-32" of beam at the 4" waterline on a typical shallow-arch bottom for most tandem teams to feel comfortable, stability-wise. Experienced paddlers can go somewhat narrower, but you do pay a stability price and obviously, the 27"-28" beam on many solo boats isn't an option.

For your first stripper I wouldn't go far into removing stations and/or otherwise messing with the design. You already have plenty to learn and figure out on your plate. The best bet is nearly always to find a decent design that's at least in the right ballpark for what you're looking for, follow the directions and don't get too creative. First-timers have a nasty habit of going off on their own and messing up a perfectly good boat. There will be plenty of time to become a canoe designer (or re-designer) later, after you've mastered the building process.

 

[BFC fan]

Dave
I took the lines from the F17 and mirrored the bow sections to the stern. I lofted and faired a new hull and then took new lines from that. The finished design has a beam of 33.5"

 

[BFC fan]

and here's a 15ft version with a 32" beam

 

[disenmann]

Thanks Tim. I've been playing around with DelftShip and came up with pretty much the same. Haven't decided what I'm going to do yet.