I'm not a techno-geek of canoe paraphernalia/geometries/intricacies.
So, let me humbly ask this of the canoe gurus:
What effect on a canoe's stability would negative rocker have?
Literally, with a string from stem to stem, across the full length of the canoe, there is approximately 1 1/4" space.
Does this disappear with the person's weight in the solo seat - or not?
Friggin' canoe is damn near uncontrollable and tippy as a drunk on Saturday night.
Reckon I ought to spread it out some? Raise those tips up?
Would that help with stability?

it sounds like a very sick canoe, i think they call it hogging. need to know make and material of canoe. it might be fun to paddle a canoe that handles like a saturday night drunk.

I call it "swayback"....... like an old horse or an old barn. I have seen a lot of plastic canoes with swayback. Why? I sometimes think maybe kept outside and upside down under a heavy snow load caused the sway.

I am not sure how you can get the stems up and the sway down short of adding a rigid keel

OK - my question is - what effect does this have on the stability of the canoe?
Does this make it tippy?
Will lengthening the seat and thwarts correct this?

yes, extremely tippy. no and no. as is a canoe with this problem is useless. i can't give any more info without knowing what type of canoe this is. i've rebuilt several canoes that were considered beyond repair. don't give up, show us your canoe, we (I) won't laugh.

glue and guts can fix a lot of stuff.

The canoe is a Dagger Sojourn, Royalex - 15 feet. Vinyl gunwales, wood thwarts, seat.
Pictures could be seen in the for sale section.
Do you need detailed photos to help me out on this?

quote jwartman59: "yes, extremely tippy. no and no. as is a canoe with this problem is useless. i can't give any more info without knowing what type of canoe this is. i've rebuilt several canoes that were considered beyond repair. don't give up, show us your canoe, we (I) won't laugh.

glue and guts can fix a lot of stuff."

When a canoe is "Hog backed" the mid, normally wetted area in the center of the canoe isn't seated in the water as it should be. So, less wetted area, the less stable the canoe. Plus, with stems dug into the water, control is very difficult.

The Sojourn is a good canoe, albeit a little "Lively" normally. If it is "Hog backed," that would be a scary beast to paddle IMHO. That's puzzling for me. I own a Dagger Reflection 15 and owned a Dagger Suwanee in the past. The royalex was very heavy and well made. Sounds like it was stored sitting on the ground in the weather a lot of years? Hate that!

I have a Royalex Dagger Reflection 15 (2 of them) that I bought in 1990. These canoes had a tendency to "oilcan" while paddling but they never lost their shape. I wonder what your canoe was subjected to.

I looked at the Madriver site. They have some suggestions for Royalex repair:

"Again, be creative. You can force a hull "out" by running a down brace from a thwart or yoke ending with a plywood or foam pad against the hull. If a thwart or yoke is not in proper position, make a temporary cross member and wedge it under the gunwale to anchor your down brace."

I think that is your answer.

Try to get the swayback popped out to the original curvature. It will take several specially designed "ribs" (forms) to get her fair. (sort of what you do in making a cedar strip canoe). The trick will be keeping her fair after you pop out the makeshift ribs......... heat can be a friend and an enemy to Royalex. Maybe you could shape it and then fill it with boiling water ....... not a very practical idea but maybe worth if you could get a lot of hot water ????

I would be tempted into making ribs that would hold her shape and that you could paddle with...... a layup of carbon fiber ribs would be the ticket........ just a thought.

Joe, thanks for the thoughts.
I really have no idea where to start, but I really wanted this thing on the water this year.
So many things to do.

I looked at the pictures and it doesn't look hogbacked to me. I wouldn't attempt to widen it and certainly not increase the rocker. Increasing the rocker is likely to make it more tippy. I think the design makes it "tippy".

Have you actually tipped in it? Or does it just feel like it's going to tip?

Yes - I have found myself upside down in the middle of a lake with a long way to get to shore.
Unsettling.

Now I feel it necessary to elaborate on something.
I make my living as a higher-range custom knife maker, and as such, spend more than a little time discussing finer details in a digital world - just like this.
I know how things can take off on a tangent with only one word.
If you look at my first post I never said it had a "dip" or a hogsback, etc.
Someone else mentioned that and then off she goes.
I said, "....with a string from stem to stem, across the full length of the canoe, there is approximately 1 1/4" space."

Key phrase there being "across the full length".

A hogs'back, (which is knife handle terminology as well) (Or the dip suggested by long term storage under snow, weight, etc.) suggests a geometry of starting at Zero, GRADUALLY working to a maximum distance and then returning to Zero.
This canoe does NOT do that.

Only about 8 inches or so from the maximum curve/apex of the stem the string goes immediately to 1 1/4" gap and then maintains that constant distance "across the full length of the canoe" (as dictated in the first post) to within a few inches of the opposing stem.
It's almost like the bottom of the hull is completely flat and the last foot of each end, is pushed down into the water by the configuration of the hull.

Why this would make that canoe so spooky to a novice like me - I don't know.
But I don't like getting wet.

I want to be on the water - not tearing my canoe apart and experimenting.
If someone has a shorter "distance" of fixing this thing, I'm all for it.
I make that statement because I work seven days a week in the knife shop the way it is just attempting to keep up with demand.
In what spare time I have, I'd like to be in the fresh air enjoying myself, not........ you know what I mean.

So, I wonder if this reiteration of the dilemma can solicit any further solutions??

Thanks for your help guys, I know this is not easy trying to help someone online.
Been there.

Now I find myself on the other end.

Thanks.

It sounds to me like the thwarts were replaced and are too long. This will cause that problem. Try removing them and pull the gunwales in to see if that fixes the problem.

quote jhb8426: "It sounds to me like the thwarts were replaced and are too long. This will cause that problem. Try removing them and pull the gunwales in to see if that fixes the problem. "

+1 on this idea

If you pull the gunwales IN - it will push the stems down FURTHER and increase the gap distance to the hull.
Think about that just a second - if you pull the gunwales in, you are in effect increasing the length of the top of the canoe.
I just pulled off the framing of the seat and thwarts.
Increased the seat frame four inches and it pulled the rocker to almost zero instead of -1 1/4".
I then put in new thwarts to accommodate the proportionate increase at their respective locations.
Wet and rainy here right now so I'll have to wait a day or so to give her a test paddle.

quote KarlBAndersen1: "
Now I feel it necessary to elaborate on something.
I make my living as a higher-range custom knife maker, and as such, spend more than a little time discussing finer details in a digital world - just like this.
I know how things can take off on a tangent with only one word.
If you look at my first post I never said it had a "dip" or a hogsback, etc.Someone else mentioned that and then off she goes.
I said, "....with a string from stem to stem, across the full length of the canoe, there is approximately 1 1/4" space."
Key phrase there being "across the full length".
A hogs'back, (which is knife handle terminology as well) (Or the dip suggested by long term storage under snow, weight, etc.) suggests a geometry of starting at Zero, GRADUALLY working to a maximum distance and then returning to Zero.
This canoe does NOT do that.
Only about 8 inches or so from the maximum curve/apex of the stem the string goes immediately to 1 1/4" gap and then maintains that constant distance "across the full length of the canoe" (as dictated in the first post) to within a few inches of the opposing stem.
It's almost like the bottom of the hull is completely flat and the last foot of each end, is pushed down into the water by the configuration of the hull."

Sorry, I used the term "Hogbacked" because that is the term that is used in canoe lingo to describe negative rocker that I thought you were describing?

You are correct in that lengthening the thwarts will increase rocker while shortening will decrease it further. Good luck.

Gotcha - sort of.
Hogback means the same thing no matter what topic.
Look at a hogs back.
Point is, it's not really "rocker", which comes from the bottom rung on a rocking chair, where an end gradually increases its distance from a given point.
This is a STRAIGHT LINE from right at the tip of the stem to the other stem.
A straight line. Not a rocker. Not a hogs back. Nothing gradual.
It's like JUST the very ends of the stem are pushed down, not like there was a gradual dip to the center.
Regardless, I lengthened the seat.
And the thwarts as well to compensate for their proportional added length with the seat extension.

I'm really anxious to get her on the water.

quote ozarkpaddler: "

quote KarlBAndersen1: "

Sorry, I used the term "Hogbacked" because that is the term that is used in canoe lingo to describe negative rocker that I thought you were describing?


You are correct in that lengthening the thwarts will increase rocker while shortening will decrease it further. Good luck."

You are correct. I had it backwards. Sorry for that.

quote jhb8426: "It sounds to me like the thwarts were replaced and are too long. This will cause that problem. Try removing them and pull the gunwales in to see if that fixes the problem. "

quote KarlBAndersen1: "If you pull the gunwales IN - it will push the stems down FURTHER and increase the gap distance to the hull.
Think about that just a second - if you pull the gunwales in, you are in effect increasing the length of the top of the canoe..."