Anyone built an 18' pirogue?

[Gatorgrizz27]

I've built 14' and 16' pirogues, I'm considering going for a "big one", at 18'. The primary reason for it is to go really wide in the middle for stability, about 36" across the bottom. If I go that wide and stretch it out to 18', it should keep a decent amount of glide rather than turning into an inefficient barge. There are a lot of tripping canoes with those dimensions, and around 2"-2.5" of rocker, so it should be ok.

Most of the 18' canoes seem to stay narrow in the bow back a ways, then flare out behind the front seat, and pinch back in in front of the rear seat, like this one: http://www.savageriver.com/canoes/recre ... /blackhawk

Is this just to prevent the paddle from hitting the gunnel, or to let the boat sit deeper in the water for better stability and handling, or is it somehow a more efficient hull shape? Idon't expect maneuverability or portability to be great, but it would be for more open water and only used with 2 people. It would be used to haul camping gear with coolers, dogs, etc, for two people to fish out of (possibly standing in very calm water), and to duck hunt from.

I'm thinking I can get it all out of 3 sheets of plywood, I'd like to keep higher freeboard as well, with sides 12"-14" in the middle and a few inches higher at the bow and stern. Not sure if I'm going to do a true "double ender" or if I will slice one end into the Y shaped stern like Chuck did on his swamp girl for a trolling motor or rudder.

Thoughts or problems with this, anything I need to consider?

 

[Kayak Jack]

That is a pretty severe example of the craft. When you used the term "pinching", you were accurate. Based on personal experience and stoutly defended opinions, all paddlers I know have personal preferences.

So, a couple guys on here for you to communicate with back channel are Matt, and Seedtick. Seedtick has built a lot of pirogues "by hamd and eye", and they're beautiful water craft. Matt designs and builds very nice boats, and sells both plans and kits. He can furnish both logic and numbers to justify what he says.

I wish you good fortune on your boat.

 

[beekeeper]

My thoughts for you to consider based on the information and example you gave.
30" to 32' max floor width. Wider will reduce the side flair.
Sides flared to max of 38" at the widest beam at a depth of 8" not the 13" depth stated for the canoe. If the max beam is higher the boat becomes too wide to paddle easily. For me a boat that is 34" wide at 8" high where I sit works well for my seat height. A double paddle will help with the wider beam. The sides of the canoe are pinched in to accommodate the more vertical stroke of the single paddle.
Tumblehome the sides above that, to the height you want (12" -14" at the stems would work for me) and the inside width (mine is 24" where I sit) you can live with.

"anything I need to consider?"
1.How will you transport it. Seems long for car topping or bed of a pickup.
2.How much will it weigh.
3.Will you need thicker plywood or more bracing because of the increase in size.
4.If you are comfortable with or think you will use a trolling motor, why not build another type boat that would be even more stable?

Unless someone has built a boat and used the same way you will, "You will have to go to know."

beekeeper

 

[Gatorgrizz27]

Thanks for the input so far. I'm pretty set on the 36" width as that is the major design factor for stability. Dogs walking around in the boat, hauling a lot of gear, being able to stand and cast, etc. I've got a 14'x32" Jon boat and it is not quite where I want it to be. The length is really a secondary factor to prevent it from bogging down in the water with as wide as it would be.

I hear you about the max beam making it hard to reach the water and paddle, but I was thinking it wouldn't be too bad as a 2 man boat. My 14' pirogue has a 25" bottom and 35" beam, I don't have any difficulty sitting just behind the middle with a single paddle. With 2 people in the boat, one is far forward and the other far aft, where it is much narrower. I would think if I chopped my boat right in half and added 4' keeping the bottom shape fair, it would end up around 36" on the bottom and 42"-44" on the top, without making it any wider where the paddlers are.

The boat I linked is a pretty extreme example of the shape to clearly show what I was talking about, most aren't anywhere near that but it is still somewhat noticeable.

To be honest, I'm still really torn about what type of boat I want, which will probably never end as I've got the BBV :lol: It's something between an 18' canoe, a wooden copy of the Gheenoe, the Robb White sport boat, and Bateau's FS18. At less than planing speeds like a trolling motor, a boat with a double ended shape should be faster than one with a squared off stern, and I don't expect to use it with a motor all of the time.

I'll be trailering it, as I drive land rovers now instead of trucks, but with 2 people it could be lifted on and off my utility trailer with an extended tongue rather than having to launch it by submerging the trailer. My 14' boat weighs in at 47 lbs out of 1/4" ply with 3 ribs, I would think I could keep it under 100 lbs with 5 ribs and some reinforcing strips/small keel along the bottom.

I'm sure I will end up with many more boats, but a "pirogue style tripping canoe" has appeal for its cost and quick build time.

 

[oldsparkey]

I stretched one out over 17 feet and was talking with Uncle John ( Uncle John Pirogues ) several years ago about doing it and he told me about a guy who was running swamp tours in south Louisiana. He was using a 21 foot Pirogue the guy made to take tourists back into one of the swamps for sightseeing tours. It was a modified Uncle John Pirogue.
That was many years ago and I do not remember who it was that did that.

Chuck.

 

[tx river rat]

My Northwind is 17 ft 2 inches at less than 60 lbs with decks so you should be able to stay under 75 lbs.
The canoe you showed is a racing style hull and the wide part is for one thing ,thats to make the required measurement for width at a 4 inch water line.
If you look at most canoes they have very little flair, most racing perows are the same very straight sided.. At your projected width and two folks paddling straight sides will be a help or very little flair for solo paddling go to a double paddle.
Flair and rocker is governed by a several things .
Length and width both help stability so at 18 ft and 36 inches you should be like a rock on the water.

Will be watching this one
Ron

 

[seedtick]

Like most things in life, boat design is full of compromise and tradeoff. You can't have one that's infinitely maneuverable and yet tracks like train. What works for you likely won't be the best for someone else. Having said that, I'll offer my free opinion and you can take it as no more than an opinion.

First off an 18' pirogue with a 36" bottom is a big pirogue, sure there are bigger ones and bigger ones can be built, but this size will carry a quite load.

You're looking for stability, I'd flare the sides out to about 30 degrees instead of nearly vertical. As the boat leans, the flare will increase the water footprint and improve stability. The trade off is that if you keep the 36"bottom and flare the sides, the top width will increase and you'll have to move farther away from center to paddle comfortably. For increased stability once you're stopped, consider putting a section of 2" pipe through the bresthook and bottom at each end and push a spud pole through it into the mud to hold the boat.

12" to 14" sides at midpoint also make it difficult to paddle - unless you're tall and/or have long arms. My builds usually have about 9 or 10" sides at midpoint. Beekeeper likes tumblehomes for his craft and they work really well for him. Pirogues are not for open or white water paddling. If you happen to be in a little wind and waves then flared sides that catch less wind will be a benefit over straight sides. If you're carrying that much load that you need 14" sides, then you probably need a bigger boat

Just my first impressions, I'm always interested in what other folks do get to the perfect craft for their own use. Please keep us posted as you build.

thanks

 

[oldbuffpilot]

You probably already know this but here it is just in case. Matt of JEM Watercraft http://www.jemwatercraft.com/ will design a boat for whatever you need. He has done this for me and it has been a good experience. The fee is modest and the communications during the process was more than satisfactory. My boat isn’t quite done but I have confidence it will exceed my expectations. In my opinion it is an easy way to get a boat that serves your individual needs.
BTW my new boat looks a lot like a Ghenoe.
Andy

 

[tx river rat]

The above conversations prove one point
(There ain't no perfect tent,wood,boat,hatch,sleeping bag or women)

Seedtick builds some awesome boats and I highly respect his opions, the same about Chuck and Jem has it down to a science. I think the use of the boat will be
the thing that makes your choices.
My views come from running small lakes and rivers that have big deep holes rapids shallow water just about any kind of water you want to paddle and a abundance of wind. My boats are paddled long distances up and down river and I sometimes do a little racing. so speed , ease of paddling tracking and if you have read any of my trips they have to carry a pretty good load.
That gives you and ideal of why I like the boat designs I do.
Ron

 

[Gatorgrizz27]

Thanks for all of the replies, I'm glad to see this place is still active!

I understand about the flare and secondary stability, and can definitely feel the close to 30 degree flare on my 14' boat, however I think I relied too much on that alone with a 25" bottom. The boat will not flip, and you can feel it get very firm when tipped over on it's chine. It would probably even be fine to shoot out of, but when paddling with two people or standing it rocks back and forth so much that it would be easy to lose your balance and topple out of.

I had expected great secondary stability to make up for poor primary stability, and it probably would be fine for something like a sea kayak, where you are stationary on the floor of the cockpit. Now I think stability is more of an overall picture, where you need the right amount of both. I'm not calculating it, but if the point where my boat can flip stays the same, I think it would work better for my needs with something like 50/50 primary/secondary stability, rather than the 20/80 it feels like it has now.

A rough and dirty "formula" would look something like, and obviously side height will affect the beam, so it needs to be kept the same when comparing boats.

"Beam (B) = total stability (St)", where we consider total stability as the force required to actually flip the boat. A boat with a 40" beam will be harder to flip than one with a 30" beam, regardless of bottom width and flare.

"S1 + S2 = St", which is the same as "bottom width + side flare = beam" (resistance to flipping)

"Bottom width (primary stability or S1) + side flare (secondary stability or S2) = beam" (A boat with a 40" bottom + 0 degree flare will have a 40" beam, as might a boat with a 30" bottom + 20 degree flare, as well as a boat with a 25" bottom + a 30 degree flare). These boats might all flip around the same point, but they will all react much differently.

To determine a "balance" between primary and secondary stability we have to compare those numbers. Comparing inches to degrees is meaningless, but the number of inches added to the beam by the flared sides alone can be calculated with a trig function. We want the right amount of beam coming from the bottom width, and the right amount coming from the side flare. I would suspect that rather than "a 30 degree flare is better than a 25 degree flare for all pirogues", we would find that the wider bottom a boat has, the more flare should be added to it, at least for boats that you want to be able to stand in.

Obviously Matt at JEM could calculate actual stability moments for different hull shapes, this would just be a simple chart where you pick the beam you are ok with and it tells you the ideal side flare and bottom width.

I could work on a chart after I get back from traveling if anyone is interested in building some models or boats to try out, hopefully that makes sense.

 

[Kayak Jack]

Now, you are speaking in logical, mathmatical terms. These are solid, and work to minimize emotion. The "rolling moment" required to roll a boat beyond its capability to remain upright has many variables. Unless you possess a highly sophisticated computer program, the easiest and only other method is to do scientific experiments with a real boat. Maybe not something you really want to undertake?

Some variables include beam, hull cross-section (flat bottom, semi-vee, semi-rounded, etc.), center of gravity (CG) for the combined boat and load configuration, slope and height of sides, etc. To obtain test results that are reliable and can be replicated, we have to be carefully methodical.

Simulate gear for fishing or camping, by securing a measured load into a boat, say, 50 pounds on the floor, rising no more than, say, 18" above the floor. Secure an imitation paddler in the seat, say, 175 pounds. Balance this load fore and aft so the boat is trimmed in a realistic fashion. Calculate the CG for this assembly. Tie a line onto the assembly at, say, shoulder height of the simulated paddler. Pull the line at a right angle to the keel line, and parallel to the water sruface until the boat capsizes. Measure required force at varyious angles of roll.

Of course, there will have to be something holding the boat from merely sliding sideways through the water - an underwater pivot point. Placement, and even the shape of the face of this apparatus, will become one of the variables too. Such experiments, to have any value and reliability, have to be conducted very carefully for consistency. Altering any single variable will affect test results. Also, the boat is static, not moving through the water. The load has to be secured to the boat to become immovable during the entire experiment. Any weight shifting destroys the set up, and makes it a whole, new experiment..

Summary: it isn't necessarily easy to do it correctly. But, it is easy to do it wrong - in several hundred ways - and muddy up the usefulness of the information.

 

[beekeeper]

https://www.youtube.com/watch?v=XDUIf7IG2BU

 

[Wannabe]

Imagine that. Having the skill and confidence to rip and crosscut a(what appears to be) 4 to 5/4 board without a fence or mitre gauge. and stand behind it while doing it. Me---I'm not there yet Nice video Bee, Thanks
Bob

 

[hairymick01]

Have a look at this one. Put a 3 feet plug in the middle and you are done.

http://www.jemwatercraft.com/proddetail ... Pirogue500

I'll go back to sleep now.

 

[beekeeper]

Any mechanical test for stability should include timing of movement. How fast a boat leans or rolls probably affects one's ability to stand in it more than how much force it takes it to turn over. Depending on the shape of the hull some may firm up faster than others. The boaters skill and abilities probably contribute more to successful standing than any one design feature.
After testing or computer calculating the stability of a hull the question becomes how much is needed? In other words how much is enough stability? I don't think that can be computed or tabulated from testing, too many variables and opinions.
The design elements of a hull that contribute to stability are known. Incorporating them and maintaining the trade offs into a useful boat is the challenge. The builder won't know if the choices were correct until he uses the boat.
Different types of boats have developed and evolved from many years of real world testing by many different boaters. Each of these do certain task(goals) better than other designs and meet other common functions well enough. Examples; Kayaks = open water hunting boat, Canoes = large capacity big water tripping vessels.
The "marsh pirogue" is a boat designed (evolved) as a hunting, trapping boat. Its tasks(goals) include hauling heavy loads, shooting platform, lots of entering and exiting, paddled seated, or poled standing up. It operates in open water and windy conditions.
Its design allows it to meet its primary factor (stability) very well. It sacrifices little in other desired criteria, because it is a balanced design. Its fish form allows the load to be forward of center. This trims the rocker and allows the paddler to sit closer to the stern where the boat is not too wide to paddle. The wide angle of the sides increases the beam above the water line. This gives the boat a wider overall beam for more capacity and stability but helps keep the waterline somewhat streamline. The wind signature is lowered because the sides don't stand as tall. They also present a "rounder" profile to side waves helping the boat to ride over the wave. The bow breasthook is exaggerated to spread the sides to help defect waves.
Designing and building a boat requires picking the features that meet the needs and understanding the trade offs. Sometimes it involves reconsidering your goals. As Ron says there is no perfect boat. I don't know much stability Gatorgrizz needs or wants but it may be more than he can build into a pirogue, and meet his other needs. Only way to know is build something and try it.
A stabile platform for fishing has always been a goal for me. Not the same as standing stability, but stability never the less. Building with the sides flared 25 to 30 degrees, and lowering the beam width, tumblehomed to maintain a width I can paddle and reducing the rocker has been the best improvement I have made in my builds
I'm not disagreeing with other post or ideas, just presenting food for thought and explaining my suggestions.

beekeeper

 

[Kayak Jack]

A friend of mine can walk the length of a kayak whilst it sits in the water. While I - well, I hang onto the gunnels pretty good. sigh

 

[beekeeper]

A friend of mine can walk the length of a kayak whilst it sits in the water. While I - well, I hang onto the gunnels pretty good. sigh

I thought "hang onto" was the reason for gunnels. :roll:

beekeeper