what's the purpose of having a "bulge"?

I see some canoes that have the gunwale as being the widest part. Other canoes flair out below the gunwale to produce a “bulge”. what are the effects, good and bad, of having this bulge? thanks.

It’s called tumblehome. The canoe isn’t bulged so much as the gunwales are tucked in, which in turn creates the “bulge” you see. Makes for more pleasant paddling as the paddler doesn’t have to reach so far to get the paddle and hand over the gunwale.


this is what i wanted to know. thanks.

I’ve heard say that it impresses some of the ladies.

There are several kinds of tumblehome
some hulls are wider down low -tumblehome so the paddling station is narrow enough to allow a vertical paddle plant.

Shouldered tumblehome is what you are describing…a variant to do the same but with the widest point of the hull about two inches below the gunwales.

Reduces your radar cross section
Tumblehome wave piercing hull

A return to a hull form not seen since the Russo-Japanese War in 1905, the Zumwalt-class destroyer reintroduces the tumblehome hull form. Originally put forth in modern steel battleship designs by the French shipyard Forges et Chantiers de la Méditerranée in La Seyne in Toulon, French naval architects believed that tumblehome, in which the beam of the vessel narrowed from the water-line to the upper deck, would create better freeboard, greater seaworthiness, and, as Russian battleships were to find, would be ideal for navigating through narrow constraints (canals).[52] On the down side, the tumblehome battleships experienced losses in watertight integrity and/or stability problems (especially in high speed turns).[53] 21st century tumblehome is being reintroduced to reduce the radar return of the hull. The bow is designed to cut through waves rather than ride over them.[48][54] As mentioned above, the stability of this hull form in high sea states has caused debate among naval architects. The tumblehome has not been featured in USN concept designs since the Zumwalt class.


I use mine to rest my digital camera
while I change batteries or the memory chip.

“thanks but I’ll have another slice”
“I’m working on my tumblehome!”

I’m with Slush
My bulge started in my mid 50’s and has grow larger over the years, er, oh, you meant in a canoe. Never mind!


Interesting new thread…
Which has more tumblehome, the hull or the paddler;-) At last, a contest in which I may actually be competitive!

Looks appeal to most folks
With all due respect to esteemed canoe designers: “Advantages of Tumblehome” is a myth. Yes, tumble home looks sexy and has sold many canoes.

In quartering waves it can cause water to shoot over top of gunwales when waves hit top curve of tumblehome. Adds momentum to this water. Yes we all try to avoid quartering waves. There are times when you can’t.

The distance at which you can get vertical paddle shaft is dictated by maximum beam, not the narrower region at the return of the tumble. If you can’t get vertical paddle while sitting or kneeling centered on the keel you need to work on technique and/or find a boat that isn’t barge-like in width.

There, I said it. Have at me.

Minor quibble

– Last Updated: Jul-02-14 3:52 PM EST –

You say that the position of a vertically-oriented paddle, with regard to paddler reach, is dictated by the maximum width of the canoe, and that is true. The thing is that you are not considering is the fact that lots of people paddle with their lower hand slightly below gunwale. One advantage to doing that is that having a greater distance between your two grip locations decreases the force that must be applied by your hands/arms for a given amount of paddle thrust (simple "lever" mechanics explains that). Racers certainly do it that way, which is the main reason the gunwales of racing canoes are tucked in even more than other tumblehome designs.

I myself paddle with my lower hand passing a bit below the top of the gunwale. That doesn't mean I always prefer tumblehome hulls though. For basic power paddling when cruising, yes I prefer that. For most other kinds of paddling I can do without it, and would prefer that if tumblehome is there, that it's minimal. The canoe I paddle the most, a Mohawk Odyssey 14, has a slight bit of tumblehome at the top of the hull while the main portion of the hull has a traditional profile. Sitting in the boat, I can't even tell the tumblehome is there, and the fact that it's slight means I can still lever the paddle shaft off the gunwale for power pries just like in a non-tumblehome boat.

I have never considered tumblehome as a reason for buying a boat. I considered what the hull's best performance features were, and whether that kind of performance suited my needs, and if the boat happened to have tumblehome, fine, and if not, fine. I've talked about hull performance with many people I know, and the subject of tumblehome was never part of those conversations - at all. The only thing that mattered is how the in-water parts of the hull performed, or whether the hull was as stiff or as light as desired. I think you are really "reaching" to say that people are choosing boats based on the visual appeal of tumblehome. Maybe somebody out there has done that, but I'm very sure that nobody that I know has approached boat-choosing in that way.

some good points are being made
but I lean mostly toward what mv says. Tumblehome is not all that its cracked up to be. Another thing I don’t like about it is that it tends to offer less stability when heeling a canoe for turning maneuvers. DY’s tucked shoulder vs. tumblehome is a fair compromise.


Yes, I paddle much of the time with my lower hand below gunwale. I don’t think it has much bearing.

Not saying everyone buys on looks. I believe that it isn’t as beneficial to performance as canoe marketing types have made it out to be. Tumblehome is a detriment, especially when it sloshes water into your canoe in quartering waves. I think “shouldered tumblehome” was a nod to the fact that tumblehome isn’t such a good idea after all.

Thanks for answering in a civil way.

Yeah, and to add a little more…

– Last Updated: Jul-02-14 5:26 PM EST –

..., I really have no desire to own a strongly tumblehomed boat. I don't have any need for that.

As far as your comment about tumblehome not making any great difference in paddling comfort, for my way of paddling, I agree. My widest solo canoe has no tumblehome (and it's my rough-water boat so, to modify what I said above, I wouldn't want it to have any), and I honestly am not aware that the tumblehome isn't there as my lower hand passes just below the edge of the gunwale.

Oh, and to modify what I *just* said, it's worth noting that the little bit of tumblehome on my Mohawk doesn't really detract from its rough-water capability. It's actually a pretty good boat in waves and rapids.