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Build design thoughts?

C_Brice

Well-Known Member
May 12, 2005
48
0
Iowa
I've built two in the past, both 20 years ago and not worth salvaging, and am getting ready to start another for small water fishing. While not wanting a barge stability over speed. Generally speaking how might I address these aspects?

Rocker? Previous builds both had around 4 inches total. Will reducing this to 2 increase or decrease stability? I could see it going either way. At 185lbs the bow and stern did set in the water with the 4in. of rocker but not by much.

How wide at the gunnels is too wide to paddle solo effectively? Previous was 32 inches, thinking about trying 34. Even wider? (I'm 5'10")

If I go wider am I better off increasing bottom width or flair? Combination of both? Previous had 24.5 inch bottoms and it seems that many pirogues have much less flair then my previous builds. Is their a preferred midship angle? Not worried about just using 2 sheet so I can make the bottom wide if it gets me what I'm looking for.

THANKS!
 
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oldsparkey

Well-Known Member
Aug 25, 2003
10,444
113
78
Central , Florida
www.southernpaddler.com
WOW .....Those are some loaded questions. I would say it all depends on what you like and are comfortable with. You are building it and this way it will be made for you.
Everyone has different likes and dislikes. Myself I like a narrow boat since they make the paddling a lot easier. I like to have less rocker so the boat sits a little flatter but with some rocker to make turning a lot easier.
I know of a simple modification one of the guy's made. He took a Uncle Johns Pirogue and added a forth rib making the center section a little wider. That gave him some extra width ( additional stability ) but strayed with the rest of the design to keep the paddling easy.
Matt at Jem Watercraft has some designs that might be what you are looking for. It would pay to take a look at them. You might find a combination of designs that could work for you.

Chuck.
 

C_Brice

Well-Known Member
May 12, 2005
48
0
Iowa
Thanks Chuck. Honestly one thing that pushed me away from pirogues and kayaks was the sitting on my butt as i got older. Regardless of all the seats I've tried about 2 hours on my butt, legs in front was all it can handle. Goal is to build a fishing pirogue that I can install a higher seat/kneeling thwart combo.

Ideas since my post.....
- 12ft (max for a couple reasons)
- 27in bottom
- 34in at the gunnels
- 12in sides (maybe 13 if I need higher?)
- 2-3in total rocker

Should gain initial stability yet allow me to keep most of my secondary from the flared sides. Fingers crossed I can get a thwart high enough to not trap my size 10s.
 
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beekeeper

Well-Known Member
Mar 4, 2009
1,849
52
You posted as I was typing. Disregard if you want to.

Could you give us a little more information?
I assume you are talking pirogue design (flat bottom, hard chine, etc.)?
How long was your boat/boats, and how long do you want the new one?
Rocker ".....4 inches total." means example 2" bow rocker plus 2" stern = 4", or 4" on each end?
Will the new boat be the same length and have the same pay load (you 185 lbs. + same gear}?
Your 32" beam was at what height above the floor? How high is your seat? Do you use a single or double paddle?

Reducing the rocker probably effects tracking more than stability. If you were satisfied with the way your boat paddled I would shoot for similar rocker/trim.
I prefer a max. beam of 34" to 35" at 8" height where I sit in the boat. My seat height is 8" to 10" and I use a double paddle. I' 6'-0" tall and have 100lbs or so more pay load than you.

"While not wanting a barge stability over speed." For me, my boats with 25 to 30 degree sides are noticeably more stable than those that had less. If you keep the floor in the 24" to 26" range you probably want notice much speed loss.
 
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beekeeper

Well-Known Member
Mar 4, 2009
1,849
52
Thanks Chuck. Honestly one thing that pushed me away from pirogues and kayaks was the sitting on my butt as i got older. Regardless of all the seats I've tried about 2 hours on my butt, legs in front was all it can handle. Goal is to build a fishing pirogue that I can install a higher seat/kneeling thwart combo.

Ideas since my post.....
- 12ft (max for a couple reasons)
- 27in bottom
- 34in at the gunnels
- 12in sides (maybe 13 if I need higher?)
- 2-3in total rocker

Should gain initial stability yet allow me to keep most of my secondary from the flared sides. Fingers crossed I can get a thwart high enough to not trap my size 10s.
If you widen the bottom, It will reduce the angle of the sides and secondary stability assuming you keep the same beam width. It also increases your boats "footprint" and that decreases the draft. That will raise your center of gravity which could feel more tippy. Raising the side height will also reduce the flair of the sides and make it harder to clear the side of the boat with the paddle.
I'm not saying your ideas are wrong just noting how every feature affects some other one.
Not to be a wise guy, but what do you need a "thwart" for?
 

oldbuffpilot

Well-Known Member
May 13, 2014
566
23
79
Central Kansas and Central Texas
Both Chuck and JD have been good sources for me, they know what they write about.
My thoughts....I recently raised the seat in one of my JEM crawdads to 12 inches and I think it can go higher.
The crawdad is my favorite of many different boats I have built, it is a good comprise for stability in a relatively short boat and reasonable to paddle. The square stern provides more width for the short length and fits nicely in the pickup. The square stern definitely invcreases drag as you at faster paddling speed, but not enough to matter to me.
For me About 35 inches of beam works best, about 30 degrees of flare, I prefer a slight v or inverted v (concave) bottom both add stability and strength.

I rarely paddle long distances to fish so I sacrifice speed for stability. The crawdad uses an extreme flare
with some side panels that aren't really sides and taller sides that are similar to a tumble home, I'm sure there is a name for that type of boat, but I don't know what it is called. You might take a look at that concept.
I almost forgot, I no longer use a thwart, but suppoort the sides with simple braces, at this age couldn't maneuver around a thwart.

Enjoy your build,
Andy
 

beekeeper

Well-Known Member
Mar 4, 2009
1,849
52
Thanks Chuck. Honestly one thing that pushed me away from pirogues and kayaks was the sitting on my butt as i got older. Regardless of all the seats I've tried about 2 hours on my butt, legs in front was all it can handle. Goal is to build a fishing pirogue that I can install a higher seat/kneeling thwart combo.

Ideas since my post.....
- 12ft (max for a couple reasons)
- 27in bottom
- 34in at the gunnels
- 12in sides (maybe 13 if I need higher?)
- 2-3in total rocker

Should gain initial stability yet allow me to keep most of my secondary from the flared sides. Fingers crossed I can get a thwart high enough to not trap my size 10s.
I think you are on the right path to reach your goals. Most of the things we have discussed can be considered splitting hairs. Figuring out which split works best is the hard/fun part. Everything is a compromise and one change effects something else.

More food for thought/questions:
Raising the sides will increase wind issues, adds weight, and reduces flair or increases beam.
Try experimenting sitting on a makeshift seat at different heights to see how wide and high of beam you can paddle around.
For max. beam and side height you could consider tumblehome sides.
Kneeling is more comfortable for you? I would have to have a lift or be dumped out after a few minutes of kneeling. :rolleyes:
 

C_Brice

Well-Known Member
May 12, 2005
48
0
Iowa
If you widen the bottom, It will reduce the angle of the sides and secondary stability assuming you keep the same beam width. It also increases your boats "footprint" and that decreases the draft. That will raise your center of gravity which could feel more tippy. Raising the side height will also reduce the flair of the sides and make it harder to clear the side of the boat with the paddle.
I'm not saying your ideas are wrong just noting how every feature affects some other one.
Not to be a wise guy, but what do you need a "thwart" for?
If your question is why something high vs a traditional low seat it's for kneeling. If your questing is thwart vs just a higher seat a kneeling thwart is generally angled down to better conform to your bum. Seats are flat, perpendicular to the water. Just a comfort factor.
 

C_Brice

Well-Known Member
May 12, 2005
48
0
Iowa
Good question since the normal Pirogue has a wide open area. My bet is he was thinking about how a Canoe is made and paddles. Especially the way the folks paddle one up in the North Woods when kneeling. Always looked uncomfortable to me since I like to sit and paddle.
You are partially correct. You could say my preference is due to experience with canoes but it's all about comfort and effectiveness not about style. As I stated above, anymore then a couple hours on my butt and I'm hurting. Seats and/or thwarts high enough to kneel gives one options and position changes as needed.
 

C_Brice

Well-Known Member
May 12, 2005
48
0
Iowa
I think you are on the right path to reach your goals. Most of the things we have discussed can be considered splitting hairs. Figuring out which split works best is the hard/fun part. Everything is a compromise and one change effects something else.

More food for thought/questions:
Raising the sides will increase wind issues, adds weight, and reduces flair or increases beam.
Try experimenting sitting on a makeshift seat at different heights to see how wide and high of beam you can paddle around.
For max. beam and side height you could consider tumblehome sides.
Kneeling is more comfortable for you? I would have to have a lift or be dumped out after a few minutes of kneeling. :rolleyes:
Good points. Max width is basically a known factor. I effectively solo paddle a 34-1/2" wide tandom canoe. Only occasionally banging the gunnels with my double paddle if I get careless. That's why currently I'm thinking 34" wide.

I'm still torn on my "split". Part of me says to keep the bottom at 25 and gain all my width with the flair. Secondary stability should be outstanding but even the slightest twitch will rock it. Go too far the other way, wide bottom/less flair and it may feel rock solid until you go just a little too far and then you're wet. 27/34 basically keeps the same proportion as I'm used to with a little wider bottom for initial stability.

Doesn't make sense that kneeling be more comfortable as we get older does it? Honestly if I had to kneel all day it wouldn't be. But given there is also a seat the multiple available positions makes for a better day on the water. For me anyway.

Thanks.
 

beekeeper

Well-Known Member
Mar 4, 2009
1,849
52
If you are comfortable with a boat close to the 27/34, then I would go with that. The last three or four boats I have built were basically that size ( 10.5' to 12.5' long). I need to point out the max. beam is at 8" high then the sides tumblehome to 10". This allows for a near vertical paddle stroke from a 8" to 10" seat height. Without the tumblehome the beam would be 36" or more at the gunnels. Max. comfortable beam is directly related to seat, and paddler's height. It would be hard to paddle one of these boats sitting on the floor.

"Seats are flat, perpendicular to the water." I may have misunderstood what kind of boat you want to build. I have "pirogue" on the brain. Are you building a canoe or at least talking in terms of canoe seats? Pirogue seats don't have to be flat. They can be built to suit the paddler.
 

oldsparkey

Well-Known Member
Aug 25, 2003
10,444
113
78
Central , Florida
www.southernpaddler.com
I will make a bet. I bet no matter which way you go and build the boat you will find ways to improve it when you paddle it. Boats are like potato chips , one just is not enough or right , the next will be even better. The seats are the same way. Take a look at the seat I designed
for my use and then how many modifications have been made by the guy's ( Beekeepers ) here on the forum. There final seats are a far cry from mine with vast improvements.
 
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jdupre'

Well-Known Member
Sep 9, 2007
2,313
40
South Louisiana

jdupre'

Well-Known Member
Sep 9, 2007
2,313
40
South Louisiana
Chuck, that seems to have been a common design in the days of cod fishing with long lines. It seems to a be a pretty seaworthy boat. Technically a flat bottom but I'll bet it doesn't act like one.
 

C_Brice

Well-Known Member
May 12, 2005
48
0
Iowa
Thanks for all the input guys! Age old question.....1/4 ply vs. Luan?

I've built two boats, one with 1/4 BC ply, the other with luan, neither were fully glassed just taped seams and epoxied. The 1/4 was durable, able to bounce it off rocks and logs and remain intact. The luan? Wife, all 120lbs of her, high centered it on a rock in a slow stream and the inner skin cracked. Thickness aside I attribute this to differences in epoxy penetration between the two types?

So.... current build thoughts.... 26-27in. wide bottom, butt joined/smal thin scarf, pine/fir chine logs, NO ribs.

1/4 ply glassed (6oz.) outside only vs. 1/4 ply glassed both sides vs. Luan glassed both sides.... condering weight and durability which would YOU do? I'm worried that fiberglass aside the bottom of a luan build may flex too much.

Thanks again!
 
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beekeeper

Well-Known Member
Mar 4, 2009
1,849
52
Thoughts:
Epoxy penetration/strength factor was probably insignificant or can't be determined in your comparisons. My "guess" is 5mm luan epoxy coated is weaker than non saturated1/4" bc plywood.
"butt joined/thin scarf" will work if glassed over. If not a glassed backer or a rib would be needed for max. strength.
Pine/fir chine logs work well.
If you're non glassed 1/4" ply boats have been working then why add glass/weight?
One factor not mentioned is most Luan plywood are rated for interior use only. If moisture reaches the glue it will delaminate. There are some rated exterior. If you have access to exterior rated, that would be a better choice.
Another option to consider would be to glue solid wood strips into panels and then glass over them. This would reduce the weight and eliminate the non exterior luan glue problems.
 
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jdupre'

Well-Known Member
Sep 9, 2007
2,313
40
South Louisiana
I've built one boat with luan, and probably wouldn't use it again. Mine was a kayak glassed inside and out. I would consider it border line effective. Basically, you will probably save only 8-10 lbs by going with glassed luan. Pine ply is much more robust and easier to work with. You can save a few pounds by using western red cedar for the gunnels, chines and ribs. Unglassed pine ply is MUCH faster to build with. Finish the boat, one good sanding and 2-3 coats of paint. Done.
 

oldbuffpilot

Well-Known Member
May 13, 2014
566
23
79
Central Kansas and Central Texas
I abondoned the Luann some time go , my last six boats have been built using the cedar strip, stitch and glue method.It doesn't take much more time than regular stitch and glue. simply lay up the panels out of cedar. The downside is I'm sure it rquires completete glass coating. The light weight of the cedar more than compenstaes for the weight of the glass. there are some builds on this site and JEM site using the SS&G method. I have 3 12 foot boats less than 30 lbs using the technique. They are tough enough that I haven't hurt one yet. Just something to consider.
Andy