My wife is pretty happy with her Tsunami 140 but I drag her on some paddles with other people who are in other 14 ft kayaks or longer and she has to struggle to keep up. She is ready for something narrower and longer hoping it would be easier to keep pace. Shopping around on craigslist so far has turned up a great deal on a Sealution for my son and a nice 17 ft Perception Eclipse for me but she doesn’t like the fit of either.
She is 5’6" 150 and in her Tsunami, which has the phase 3 seats and can adjust the height of the front edge of the seat she has 4 inches difference in height from the front of the seat to the bottom of the thigh pads. In any other boat she does not like how high she has to hold her knees for a good 3 point contact. I think we need to move out of the poly boats but personally I’m not crazy about a fiberglass boat in our world of barely submerged tree stumps…
Primary use would be day trips on medium size rivers, small lakes, and near shore gulf paddling. Zero rapids, occasional swells maybe. If we overnight I carry most the shared items so storage isn’t a big issue.
I have two kayak dealers in range, the further of the two has most manufacturers available but the nearer doesn’t carry anything over 14 ft.
Looking for some tips on lower volume boats in the 16 ft range before I go talk to the dealers.
Other WS boats
You could try the Zephyr which comes in 15.5' or 16' lengths and also has the Phase 3. If you want even more narrow try the Tempest 165. I personally like the Tempest 170 but I like it BECAUSE it has a roomier cockpit (in my opinion), so she might prefer the zephyrs or the 165. They all have the seat that she is used to. I'm just a bit larger at 5'7", 170 pounds, but have very long legs which is why I like the 170.
Second Grayhawk
Regarding the Avocet but in the LV model. Given your preference for poly I'd try her on a Venture Jura LV or a P&H Scorpio LV.
Too bad on the non-composite.variable. I've got 3 Carbon Kevlar Avocet LVs carried over from last year that could use good homes.
See you on the water,
Marshall
The River Connection, Inc.
Hyde Park, NY
www.the-river-connection.com
hudsonriverpaddler.org
Romany
Check out the Nigel Dennis Kayak (NGK) 16’ Romany. Does about everything well. Had mine since '98. Get one used in fiberglass.
The Avocet LV has a tiny cockpit.
I’m 5’6" and 160 lbs and couldn’t even get in the cockpit with the boat parallel to the shore and small boat wakes rocking it. The Fathom LV I had test paddled earlier was much easier to fit in to.
Pirate, an Eddyline Fathom LV might be a superb choice for her.
3rd the avocet, and some other ideas
Ideally the ‘glass LV model but I know smaller folks who paddle the poly LV and like it. OTOH a friend of mine paddled one for awhile and he was 6’ tall.
Other poly boats:
P&H Delphin might also work.
Necky Looksha is skinny and low foredeck; even the 15’ LV is fast. Ruddered boat.
Lots of poly Capellas around but I found the cockpit too big.
If you can find an Eddyline Nighthawk, check it out, I think that’s a great boat for smaller people. And thermoform so it feels like composite at a lower price.
CD
There’s a poly CD Squamish (15’8" by 23") for sale in the p-net classifieds. It’s in AL, not sure if it’s close to you, but it’s worth a look at the asking price of $600. Your wife is probably near the high end of the weight range, but if not taking any cargo, should be OK.
Venture
I'm your wife's size so I'll offer a suggestion. I agree that the Tsu 140 is a relatively sluggish boat -- one of my best friends has one that I have used in the past and I was underwhelmed by it. I've owned 12 kayaks so far and my personal favorite in a reasonably priced poly boat is the 15' by 22" British made Venture Easky 15LV. With this boat I can easily outdistance my friend in her Tsunami and have been able to readily keep pace on outings with paddling buddies in all manner of longer high end kayaks. The outfitting is very comfortable and functional and the 44 lb weight is another plus for us smaller folk. The boat is very maneuverable too and has excellent secondary stability in rough water. Mine does not have a skeg or rudder but its semi-Greenland profile tracks very well. It's a bit like a slightly shorter and 1 inch wider version of its cousin, the P & H Scorpio LV.
Only drawback is that Venture (a division of P & H) discontinued the model two years ago, replacing it with the somewhat heavier Islay 14LV. I can't comment on the Islay though it has gotten very good reviews. If you can find an Easky 15LV, either new in dealer back stock or used, I think she would like it. Every person I have ever put in the Easky (which I often lend), from 5'2" women to 5' 9" guys, has commented spontaneously about how great the boat feels and how easily it paddles to speed.
Avocet RM or P&H Delphin 150
Ok iam a male at 5’8" 170lbs. I also had a tsunami 140 which was kind big on me. The tsunami has the phase 3 seat BUT also has the high back rest not the same as the backband some of the other Wilderness kayaks have with the phase 3 seat so something to keep in mind.
I also have now a Avocet RM. There is only one size in the RM (Plastic 3 layer). I put my sister in my avocet and she loved it, she said finally a kayak that she doesn’t feel like she’s in a tub. She is about 5’4’ guessing around 120lbs.I have extra closed cell padding in mine for a tighter fit. So an avocet would be a good choice.
I have also paddled a P&H Delphin both 155 and 150 . The 150 would be the better fit. Also paddled a Eddyline Fathom LV. Another good choice. Also paddled a NDK Romany but its fiberglass. That would work if you want a glass kayak.
Easiest rolling boat is the Avocet RM. Highest primary stability would be the delphin. BUT all of them are pretty good.
OP Parameters
The Avocet LV is a low deck being that the OP wife stated " In any other boat she does not like how high she has to hold her knees", at a 9.5" thigh brace height, Y the LV is not something you should get into, or try. Go with the standard Avocet or North Shore Atlantic.
The other parameter is a higher potential glide speed. “she has to struggle to keep up. She is ready for something narrower and longer hoping it would be easier to keep pace” While kayaks like the Delphin 150 and Squamish have positive attributes a faster glide is probably going to be easier to achieve with a longer waterline.
See you on the water,
Marshall
The River Connection, Inc.
Hyde Park, NY
www.the-river-connection.com
hudsonriverpaddler.org
The perfect answer…
…for keeping knees in place with no effort. http://photos3.meetupstatic.com/photos/member/3/4/d/c/member_228553532.jpeg It’s worked for 20 years for me.
As far as fast AND plastic…
Nordkapp RM…Prijon Barracuda…Prijon Catalina
Appreciate the opinion
But I don’t need links emailed to me for Phoenix craigslist or used boats in NJ being sold for pickup only
Thanks for the suggestions
I had an LV hull in mind but don’t have any experience with them and was on the fence as she likes the 140 which is not LV but after looking at a few used boat and hearing her complaint I took the measurement and realized how she kept her seat adjusted. Not many used LVs in Mississippi so I was looking for hulls I could talk to the dealers about.
And yes, improved glide is what I am after. I was thinking thermoformed/ABS type to shed some weight. I have my doubts about fiberglass for the type of paddling I do. I’d be willing to get a Kevlar composite if it made her happy but if she could be happy for a grand less that would be nice too. I like my poly boats but I think it would be tough to find the performance improvement we’re looking for with another poly.
Stellar - In advantage lay up
The Stellar 16 maybe another option. The advantage layup is ~ 38lbs at ~$2400. Lighter and less costly, than a typical glass composite. If another “new” kayak enters my stable, it maybe a Stellar. I hope to try one in the spring demo season. Good luck in the quest.
http://www.stellarkayaksusa.com/boats.html
COCKPIT OUTFITTING
You can outfit most cockpits to snug them up and get a great fit with a little seat padding and some minicell foam contoured to fit the paddler and better hold them in place. In many cases, it doesn't take much, and you can often dispense with seat padding and work on padding out the knee/thigh braces.
If you're even just a little bit handy, you can swap out factory seats for others to provide better, more snug, and a more comfortable fit as well.
These approaches can open up a lot of options in good paddling, faster candidate boats that you and she might/would otherwise discard, and perhaps make available some used boats that are better values and possibly close(r) to you rather than unnecessarily restricting your potential choice set and/or having to travel (or ship from) farther afield..
A little work can get her a custom fit in a 'better', more appropriate boat in which to happily -and while "keeping up with the Joneses" -
PADDLE ON!
-Frank in Miami
A bit smaller but can comment
Just saw this thread. Looking back thru all the comments, I suspect that many underrate the value of glide.
Romany (regular, NOT LV) would be a fit for her, but it would be faster than the Tsumani because it is longer and narrower. Not really a big glide boat compared to others in its class. But however you get there it would be faster, and it is an old boat at this point so I suspect you could get a decent price on one.
The Avocet has a similar character to the Romany, again it would be faster but is also about maneuverability. I would strongly suggest that you do not go with an Avocet unless she sits in it though. It creates a bit more of a froggy legged position than boats like the Romany with clearly enunciated thigh braces. Some have no issue with that and some find it very uncomfortable. I am pretty sure the LV would be uncomfortably tight, but if one is around it is worth a sit.
A boat that she might fit and can, up to about 4 knots, smoke a lot of people you might paddle with in acceleration is the old P&H Vela. It does weather cock, you need to learn to love the skeg, but they are not highly regarded since it is such an old model. Regarding your tree stumps, the older P&H layups are very durable. So they can be gotten cheap. People tend to love it or hate it, but if it works for you it can be a tremendously capable little boat. I have had mine out in haystacks over my head that put two coaches upside down and, as long as I stayed relaxed, we just had a hell of a good time bouncing around.
We have a local guy very close to your wife's size - gotta be within half an inch and a few pounds - who got one and loves it. Flat water paddler, he just likes the acceleration.
The Tempest 165 is quite available in poly, lots around so you can get a deal, and would be faster by a lot than what she is paddling. It is more of a tracker than the Avocet or the Romany, but it still turns fine.
North Shore Atlantic is a good idea. Also will tend to be available used at a lesser price than newer and hotter designs, and should work well for her.
There are newer boats in shorter lengths that would probably suit well, like the Zephyr and the Delphin, unfortunately I can't talk about then because I don't have real seat time. More importantly, they may be more expensive than some of these others because they are newer. You might be best off going for something used that is cheaper due to design year or sheer quantity for the first 16 ft boat, see what characteristics she ends up liking. All of these are going to feel like a real step up from the Tsumani 140 and it might be hard to tell where that'll take her.
Seconded
The tempest 165 is definitely the way to go, if you want to get better cockpit handling (along with being a better boat overall) without going too far away from what’s familiar. The 170 is WAY too big for her though, definitely go with the 165.
used composite boats
There’s a used Anas Acuta in Florida listed right now. Price is high for a used boat but it’s the last boat she’d ever want! 
I’d keep an eye out for used Eddyline thermoform kayaks - Fathom LV, the old nighthawk 16 and even the merlin LT, they seem to come up pretty regularly in the classifieds. Maybe when spring gets here.