Load weight and trim and it's effect on stability.

lowangle al · Sunday at 10:01 AM

I've been paddling my Seliga Tripper mostly solo so far this season. I paddle from the stern seat with some light ballast (20-25lbs.) either in the bow or right behind the bow seat. I find that adding the ballast eliminates the twitchiness in initial stability that this boat has, probably caused by the round bottom. I was surprised recently when I took a friend out fishing that the twitchiness was back, even though there was a lot more weight in the boat. Usually a boat will get more stable when you add weight, so something else must be going on. The only thing I can think that would cause this is the trim of the boat.

When paddling tandem the boat has a fairly flat trim and rides high in the water. It is probably close to the 32 inch waterline that is stated in the specs. When solo, even with significantly less weight I think the maximum waterline is much wider, probably approaching the maximum 36" width of the boat. Even though there is less wetted surface of the hull, stability increases. This could be something to experiment with if you want more stability. I was never a "flat trim" guy, preferring to be bow light. This is one more reason for a bow light trim.

Gamma1214 · Sunday at 11:03 AM

I have to wonder if some of the perceived twitchiness is due to the change in hull profile from what you've gotten used to. Even the twitchiest of boats can feel stable once we've become familiar with them but changing loads cause changing handling characteristics.

One more reason to paddle solo.

gumpus · Sunday at 1:33 PM

lowangle al said:
I've been paddling my Seliga Tripper mostly solo so far this season. I paddle from the stern seat with some light ballast (20-25lbs.) either in the bow or right behind the bow seat. I find that adding the ballast eliminates the twitchiness in initial stability that this boat has, probably caused by the round bottom. I was surprised recently when I took a friend out fishing that the twitchiness was back, even though there was a lot more weight in the boat. Usually a boat will get more stable when you add weight, so something else must be going on. The only thing I can think that would cause this is the trim of the boat.

When paddling tandem the boat has a fairly flat trim and rides high in the water. It is probably close to the 32 inch waterline that is stated in the specs. When solo, even with significantly less weight I think the maximum waterline is much wider, probably approaching the maximum 36" width of the boat. Even though there is less wetted surface of the hull, stability increases. This could be something to experiment with if you want more stability. I was never a "flat trim" guy, preferring to be bow light. This is one more reason for a bow light trim.

Your friend raised the center of gravity while a normal load on the floor (or ballast) lowers the CG. It's important to choose paddling partners with a low center of gravity.

You almost made it sound like the boat rides lower and has a wider waterline when lightly loaded. I must have misunderstood.

lowangle al · Sunday at 2:16 PM

Gamma1214 said:
I have to wonder if some of the perceived twitchiness is due to the change in hull profile from what you've gotten used to. Even the twitchiest of boats can feel stable once we've become familiar with them but changing loads cause changing handling characteristics.

One more reason to paddle solo.

Yeah, I think that it is the change of the hull profile. With the weight spread more evenly the hull presents a more narrow profile and that narrowness is what made it tippy. Thinking back, the boat is twitchy with just my wife and I in it without a load. OTOH, a few days before I was out with a different friend who is a little on the portly side and I didn't notice the twitchiness at all. I guess the additional 35 lbs was enough weight in the boat to make it stable.

Solo is always good. My tall skinny friend has physical issues and prefers not to paddle and I'm good with that. The chubby guy is an
experienced paddler but I think it had more to do with his weight than either his lower center of gravity or paddling experience.

gumpus said:
Your friend raised the center of gravity while a normal load on the floor (or ballast) lowers the CG. It's important to choose paddling partners with a low center of gravity.

You almost made it sound like the boat rides lower and has a wider waterline when lightly loaded. I must have misunderstood. View attachment 147068

I considered the difference in the height of the COG, but I think that the additional 150lbs over that of my ballast would improve stability more.

With less weight in the boat I would expect there would be less wetted surface and less stability but it is the different hull profile that gave the boat stability. With the bow light trim the stern is deeper in the water and it gets a wider part of the hull in the water. I think trimming the boat this way to get that wide part of the hull water is what increased stability.

I like your ballast, it looks like he's helping to lean the boat.

Steve in Idaho · Monday at 9:45 AM

lowangle al said:
Yeah, I think that it is the change of the hull profile. With the weight spread more evenly the hull presents a more narrow profile and that narrowness is what made it tippy. Thinking back, the boat is twitchy with just my wife and I in it without a load. OTOH, a few days before I was out with a different friend who is a little on the portly side and I didn't notice the twitchiness at all. I guess the additional 35 lbs was enough weight in the boat to make it stable.

Solo is always good. My tall skinny friend has physical issues and prefers not to paddle and I'm good with that. The chubby guy is an
experienced paddler but I think it had more to do with his weight than either his lower center of gravity or paddling experience.

I considered the difference in the height of the COG, but I think that the additional 150lbs over that of my ballast would improve stability more.

With less weight in the boat I would expect there would be less wetted surface and less stability but it is the different hull profile that gave the boat stability. With the bow light trim the stern is deeper in the water and it gets a wider part of the hull in the water. I think trimming the boat this way to get that wide part of the hull water is what increased stability.

I like your ballast, it looks like he's helping to lean the boat.

Lengthening the waterline also increases stability, so I don't think that's what is causing the twitchiness when you're paddling tandem. Frankly, I think it's your friend who is twitchy.

I've noticed this with different partners in the same canoe. With some, it's no different than solo. But with others, it feels like a whole different unstable canoe.

The location and mobility of added weight makes way more difference than the amount. Eighty pounds of secure tripping gear with me in the Prospector turns it into a rock solid platform. Put a 180 lb novice in there with me instead, and I have to be more on my game to keep us upright.

Of course, there is a point of diminishing return when adding dead weight, but it doesn't sound like you're approaching that - unless I'm missing something.

Cruiser · Monday at 3:31 PM

I wonder if there isn't more than just the shape at the hull in play here .... maybe there is also some inertia at work, without the added weight it is simply the boat twitching, but if you add secure weight, you also have to get that extra weight moving, so any force you apply to move the boat is going to take more energy to get moving ...

Glenn MacGrady · Monday at 4:05 PM

Have the bow paddler sit on the bottom behind the bow seat, and then compare the twitchiness to that when he or she is sitting on the bow seat. That will help suss out the effect of lowering the COG.

I did that in Alaska in a 16' OT Penobscot with a fairly novice friend who weighed a bit more than I. At first, I was paddling bow and he the stern on a windy lake (Eklutna), and we felt the boat to be more twitchy than we were comfortable with. We then tried having him sit on bottom behind the bow seat and paddle with me in the stern. That increased stability significantly, and I was even comfortable enough to paddle some class 2 rapids with him in that posture (the Eagle River).

Tsuga8 · Monday at 9:48 PM

Chip Cochran was recently pointing out something I hadn't thought about - that where the mass 'connects' to the hull also matters. He was talking about how a standing poler, while their center of gravity is higher in one way, they connect with the bottom of the hull standing in the chines, whereas a seated paddler connects to the hull higher up and farther out from the longitudinal center, thinking about their butt exerting force on the rails via the seat. I think I'm explaining that right, and I think it makes sense. If I have this right, ballast in the bottom of the hull is much less tenuous than an additional paddler because the paddler connects to the rails through the seat, so a little lean of the head or torso acts on the rail through the seat. At least....so I think....as I understand it.

I also agree with much of what's been said above. Partner twitchiness matters, and being in a boat with someone else when you're used to paddling solo also feels quite different. I also think over-loading a boat can also make it twitchy, but sounds like that isn't the case here.

Steve in Idaho · Monday at 10:24 PM

Tsuga8 said:
Chip Cochran was recently pointing out something I hadn't thought about - that where the mass 'connects' to the hull also matters. He was talking about how a standing poler, while their center of gravity is higher in one way, they connect with the bottom of the hull standing in the chines, whereas a seated paddler connects to the hull higher up and farther out from the longitudinal center, thinking about their butt exerting force on the rails via the seat. I think I'm explaining that right, and I think it makes sense. If I have this right, ballast in the bottom of the hull is much less tenuous than an additional paddler because the paddler connects to the rails through the seat, so a little lean of the head or torso acts on the rail through the seat. At least....so I think....as I understand it.

I also agree with much of what's been said above. Partner twitchiness matters, and being in a boat with someone else when you're used to paddling solo also feels quite different. I also think over-loading a boat can also make it twitchy, but sounds like that isn't the case here.

All correct. ^
I feel much more stable in a tandem canoe when standing, rather than sitting on a seat.

Glenn MacGrady · Tuesday at 1:21 AM

Tsuga8 said:
If I have this right, ballast in the bottom of the hull is much less tenuous than an additional paddler because the paddler connects to the rails through the seat, so a little lean of the head or torso acts on the rail through the seat.

This makes sense to me. To test this, check tandem hull stability with the same bow paddler sitting and kneeling. Kneeling should lower both the COG and the average hull contact load point—split between butt on seat rails and knees on hull bottom—and hence increase stability.

Steve in Idaho said:
I feel much more stable in a tandem canoe when standing, rather than sitting on a seat.

And everyone should feel more stable in any canoe when kneeling off a seat rather than sitting on it, for the reasons stated above.

Black_Fly · Tuesday at 8:52 PM

Is your partner twitchy?

lowangle al · Wednesday at 9:31 AM

Glenn MacGrady said:
Have the bow paddler sit on the bottom behind the bow seat, and then compare the twitchiness to that when he or she is sitting on the bow seat. That will help suss out the effect of lowering the COG.

That will help minimize the twitchiness for for sure but it will also change the trim so it's not comparing apples to apples.

I do think everything said above is true but I still think there is some truth to my premise that trim can affect stability. The Seliga is the only boat I have that lacks initial stability so the effect won't be felt as much in other boats, if at all. I did an experiment this morning by paddling with me and the ballast centered in the boat and compared it to me paddling in the stern seat with the ballast behind the bow thwart. My theory would suggest I would have more stability with a bow light trim than a flatter trim but I couldn't notice a difference. I'd like to do another experiment with more weight in the boat to see that makes a difference. In this mornings experiment I was standing when I had the weight in the center and sitting with me in the stern so I think that effected the results.

Black_Fly · 2025-06-13T15:09:35-0400

The narrow bow of a tripper like a MNII can create instability without a substantial cargo load. The front paddler is often cramped and the angled hull design lends to tipsiness. It’s consistent with the purpose of the craft. That’s where a big dog actually comes n handy. You just need a retriever.

MrPoling · 2025-06-13T20:37:01-0400

Tsuga8 said:
Chip Cochran was recently pointing out something I hadn't thought about - that where the mass 'connects' to the hull also matters. He was talking about how a standing poler, while their center of gravity is higher in one

I was paddling this week in a big tandem loaded with two kids and camping gear. I was getting tired of sitting with my knees bent, but when I stretched out I felt more unstable. I even had a solid foot brace and it didn't help.

I concluded sitting with my feet flat against the bottom near the chines allowed me good, wide, firm contact to balance the canoe. When I stretched out my legs I lost the ability to push down. My butt, right over the centerline, was the main contact with the canoe.

I also decided my son was completely oblivious to balancing the canoe. I'm thinking he needs some time in the Yellowstone solo to learn for himself.

Gamma1214 · 2025-06-13T22:12:21-0400

I'm thinking he needs some time in the Yellowstone solo to learn for himself.

I like it. Certainly warm enough for swimming down there.

Load weight and trim and it's effect on stability.

lowangle al

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lowangle al

Steve in Idaho

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Glenn MacGrady

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Black_Fly

lowangle al

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