The first boat I built was a Great Auk, but at 5/6 of the
design size in Nick's book. So the (re-)design displacement was
125/216 of the design displacement. The boat is 14'2" long and
20" beam. Now I hasten to add that this was being built for
my daughter, and child growth charts indicated that she would
be something like 5'4" and under 100 pounds when she grew up,
so this was not a daft size.

Now I can _just_ squeeze into this boat. When I do so, the
actual displacement is about 220 pounds, and my build puts the
centre of gravity at least two inches higher than when Sarah
paddles it. The first time I tried it was in a force 4 on a lake
and I never got anywhere so deep that I couldn't brace the
paddle off the bottom - which I needed to do repeatedly !

I got used to her - even though she has a rounded hull shape and
sits far too low in the water, she has quite adequate secondary
stability to paddle in calm water and turns beautifully to a lean.

She really is uncomfortable in waves though, especially when not
powering along at speed. And there is a limit to the secondary
stability too, since a boat so low in the water soon dips the sheer
below the water and the secondary stability just runs out.

I built my next boat for myself, but still a low volume boat, and
this one is a fairly low-rocker hard chine design (scaled down a
little from the Squeedunk Cormorant). She is 15'3½, and under 21"
beam, with a stitch-and-glue single chine hull and a stripped
deck, so perhaps not dissimilar to yours. This boat too feels wobbly
when paddled slowly and empty, but is a lot better when loaded with
gear for a few days. Partly she has better knee braces and a tighter
padded seat, so I am in better contact (since she is mine and I've
stopped growing, I could make her fit much better than Sarah's boat).
While she is not a boat I take on day trips in rough water (for that
I tend to use the club Anas Acuta, which is highly rockered and a lot
longer, but similar beam - vastly more stable), I have had her out
in rough conditions on a multiday trip, and in some fairly rough
conditions with a bit of balllast. I have found this to be really
beneficial.

All the people on this forum will extol the virtues of having more than
one boat (any excuse to build another one...) but my take is that if
you swap boats a lot, take your stable boat out in rough conditions,
then swap to a less stable boat for a calm day, and keep swapping and
moving to rougher conditions, your paddling skill will improve more
quickly than just sticking to one boat you feel safe in on all trips.

A couple of years ago, I had the Cormorant out to the Farne Islands
on a calm day with some ballast and was able to do some fishing in
the tide races. This year, as pretty much my first sea trip, I had
her on the same trip on quite a windy day at spring tides (5-6 knots
in the channels between islands) with no ballast at all.

It did take continuous concentration and was quite wearing, but my
old fibreglass boat feels like an aircraft carrier now. So I am
convinced that a low-volume boat is good for developing skill, as
long as you also have a boat you feel safe in for those rougher
days or pushing the envelope.

If you load a boat for camping, it sinks lower, so the waterline
beam increases and the centre of gravity is lowered. That in itself
makes it a lot more stable, and the extra inertia means things happen
a little more slowly, giving you time to react. If you paddle empty,
just a little ballast, tightly fixed in the bottom of the boat, can
make a huge difference. Just a BDH drum full of wet sand behind the
seat makes a huge difference in my bigger boat - a long thin bag of
wet sand is all that fits in the Cormorant, but that's all it really
needs. Just glass in some tie-down points along the keel in front
of the seat, and fix your ballast to those - making sure there are
no loose ends to make an entrapment risk. Then just go out and play.
In rougher conditions, make sure you have companions who know rescue
skills, just in case you miss your roll. I have done reentry and roll
in the Cormorant, but it takes time to pump out the cockpit, and I
would not fancy my chances of staying upright in conditions that
would capsize me for real... With companions, I've been fished out
of the Clyde estuary (a shipping lane - oops!) and resumed paddling
in wind-against-tide conditions with no lasting ill effects. Perhaps
a four day trip round Bute over a windy Easter wasn't the ideal choice
for this boat's maiden voyage ...

Oh yes, for comparison, I'm 187 pounds without paddling gear, and
5'7" ... I can fit camping gear, food and water for six days in
this boat, but that really is about the limit, even if I manage
to lose all my excess weight :-)

Andy