Volume of C-17 VS C-18

Does anyone happen to know what the volume of the Chatham 17 and Chatham 18 are? The C-18 is what, 5" longer but a 1 1/2" narrower? How much difference in volume can there be?



Also, what about speed? I know that the 18 is not a speedy boat. Is the 17 a slug? The same? Or what?

or what
the CH18 is deeper over all, it feels like a bigger boat, as far as the amount of weight that either hull can carry comfortably I’m not sure. As far as volume is concerned I’m pretty sure there’s more volume in the Ch18.

The 18 has a longer straight keeled waterline, feels choppier in waves.

Just curious is all…
…something that I wondered about. I know that they are very different boats and have packed an 18 for extended tripping. It got me to wondering if the 17, in spite of it’s shorter length would carry the same amount of gear.



I know that you owned a 16 and an 18 and spent time in the 17. What about the effort of moving it through the water. The 16 takes effort. What about the 17?

I don’t think it will
From a usable volume standpoint I think the 17 would take less.



If efficiency was a concern I think you’d be looking at totally differnt boats like a CD extreme or Impex Force4



broad negative terms like “slug” really aren’t useful when it gets to describing the differences.



The 17 has a more foregiving handling in waves than the 18 but my time in either boat really isn’t that much. I never paddled the 18 loaded and paddled the plastic/composite 17 just a few times. I’ve never had either boat out through surf.



One thing that kinda bugs me about the composite Chatham 17 is why they use partial core material in the hull. The hexagonal white material used to stiffen the layup. In the cockpit the composite 18 had a wide section extending forward from the seat but the wider 17 has a narrower section of stiffening core material. I don’t get it,that leaves a more flexible open section without core material leading up to the chines under the feet and in the forward compartment. Seems to me they should just put in a big section extending from the skeg box and forward to the front compartment and wrap it up the chines. My recollection is that the 17 has more ringing in the hull when it slaps down on waves than the 18. Anywho look at the inside of the CH17 hull and flex those open areas then look at a CD or WS composite hull. They’re pretty much solid. I don’t think it’s an ultimate structural issue as the laminate is effing strong, more of an aethetic one or place where gel coat cracks will develop.

"slug"
Yeah. I agree. That was a bad choice of adjective on my part.

I’ve searched the archives for comparisons on the volume of the two boats and didn’t really find anything useful. There is plenty of comment on the C-16 and C-18, but I found no direct comparison of volume or specific comment on the hull efficiency of the 17 VS 18.

I was hoping that if I asked those questions I could get the specifics. I was hoping that you would respond because I know that you’ve had experience in all three boats.

Maybe Salty will comment, also?

elliptical cross section or round
the dificulty in comparing volumes between the two boats is the volume that relates to load carrying, what’s below the sheerline and what defines volume to carry stuff, what’s above the sheerline don’t correspond directly. This is one of those things where i’d want to A/B test with 75lbs of gear/water.



For some reason the plastic 17 has less freeboard/volume in the compartments than the composite one.

I don’t know
but having owned both, it’s my imperssion that the 17 has more room. Although that makes no sense (I’m going to contradict myself), because at my weight (220-230) the 18 is more boyant.


effort
Did you have a sense for which moved through the water with the least effort?

on second thought
I’m comparing apples and oranges



what I had was the plastic 17



the glass 17 is noticeable fuller volume



as for speed, it’s hard for me to say which was faster



probably the 18



the 18 DOES track stiffer, and the 17 was incredible forgiving in 3-5 foot waves



it’s hard to say what I’d choose if I had to do it all over again



Salty and gang prefer the 18, but the 17 is a nice boat too






Chathams
The Chatham 18 is certainly a low volume boat. I have camped for five days in it, but wouldn’t want to try a two week trip if I had to carry all my own water. I love it, however. It is not nearly as speedy as my High Volume Current Designs Solstice GTS was, but it more than makes up for that with maneuverability and general playfulness. I just love it. It is a boat for a more experienced paddler, as one of the salesmen called it, a “performance” boat. It has really helped my boat handling, and my roll. It is simply wonderful to paddle.



The Chatham 17 is a completely different boat. Though it also is easy to maneuver, the wider boat is suited to a wider person, I think, but also handles waves well. Alex Matthews recently wrote a book, Rough Water, in which they paddled some incredible water, and his boat is a Chatham 16. If you are considering which to buy, I don’t think the volume should be your deciding factor. I would consider instead how you fit in the boat. But they are all incredibly easy to change to fit your thighs, seat, etc.



I am a female, 135 pounds, only 5 ft 4, and it fits me well. It could accommodate someone larger, just try it.