I'm going to be finishing up an 18.5 ft. NW Cruiser when it has officially warmed up, and I'm thinking about my trim. I have a removable carrying yoke for my solo that is wide enough for this canoe. I plan on adding a 3rd seat for an additional paddler & as a solo seat for me when fishing solo in the AM when in the BWCA. (I'd never take a solo trip in this boat)I'd like to skip the permanent center thwart/yoke and just install 2 thwarts leaving the center 1/3 of the boat basically open except for the installed 3rd seat.

I know this is the configuration in many solos, but I'm not sure it will translate well in an 18.5 ft. boat. Does anyone have any input on the structural importance of the center thwart/yoke in a bigger boat?

Thanks!

I think you'll be ok. Canoecraft mentions that only one thwart is needed for canoes up to 18'. Two thwarts at the thirds should provide pretty good stiffness, plus the center seat will add some stiffness as well.

acording to Gilpatrick's book:

"When the center thwart or yoke is installed, you are done if the length is 16' or shorter, but for the longer models there are still two more. For 18' to 20' canoes, I place the other two thwarts about 42" to 44" from the center one."

For shorter boats(16 feet or shorter) a center yoke and a rear thwart would be enough. Longer boats call for center yolk and 2 thwarts,IMO.
For an 18 foor plus bost I would install a kneeling thwart instead of a standard rear thwart. The center is too wide to comfortably solo from that position. Just look at what Bell did with their Northwind or Northwood canoes, used a rear kneeling thwart.
That said I will be re-installing the third seat in my 18.5 foot NW Cruiser for my son( age 10) for fishing opener in the rear compartment like Wenonah does with their third seat in the Seneca or MN III.
My other option is the front compartment just ahead of the center yoke, and then turn the center yoke arond to face the rear when I carry. For a child this actually works very well.
Back to my point with and 18 foot boat you need the center yoke not so much for side to side but more to control the twist of the hull when it is loaded in waves.
For that reason I dont like those aluminum center seat/carry yokes there is no support for the twisting.
CB

I agree with what has been said - you need a center thwart/yoke. I'm intrigued with the yoke facing backwards. I think Esquif Canoes did this on some of their canoes.

If you look at commercial three-person canoes, the third seat is closer to the stern than the center. I'd put the third seat there.

Thanks for the replies.

I'll let you know what I end up doing. Its easy enough to put it on later if I think its a problem, so I'll probably give this configuration a try. The removable thwart will also be on it most of the time that I'm traveling. I just wanted a roomy center seat option for those couple of hours in the AM I go out by muself to fish. I'd never go far or risk sketchy conditions by myself in the boat.