This sketch is designed to show a cost effective seaworthy microcruiser the idea being that rather than build a new boat from scratch it would be easier to modify an existing second hand boat.
The boat I have used for the basis for the conversion is the Nordica 16. This boat has a good reputation and has a full length fixed keel with a good amount of pig iron ballast low down. There are many advantages to using an existing boat as a microcruiser, most notably reduced cost and time saved. One positive aspect of using the Nordica 16 as basis for a microcruiser is that very little needs to be done, only rework the cabin and close off the cockpit. Rig and hull remain unchanged
There have been a few microcruisers that I know of and most have tended to be fairly successful. The smart thing seems to be to use the central part of the boat as the accommodation area, and leave the ends free for watertight bouancy and storage compartments. I feel that trying to put in a separate cockpit on such a small boat is not worth the effort. My information is that second hand Nordica 16's can be bought for $1000 to $4000 in North America.
Some features I envisge for the above sketch is that the topsides would be sloped inwards to reduce windage and to minimise wave impact. Logic suggests that this design would handle rough conditions very well. C A A Marchaj wrote that a full length keel has positive aspects in seakeeping, further more the modified cabin has a high degree of bouancy and should provide a lot of righting moment at very high angles of heel. Chances of knockdown are reduced by the sloping of the topsides which reduces wave impact, and also by the shape of the underside of the hull which disperses wave energy from a knockdown position and by having a substantial amount of ballast low down. Unlike a lifting keel there is no mechanism that can break with a deep fixed full length keel. The major downside is of course that there is no shoal draught capability, thus access to beaches would have to be via inflatable boat.
Other microcruisers that come to mind. Matt Layden's water ballasted Paradox boat, Sven Yvird's Bris and his new twin masted next project. John Welsford's Fafnir, the Tideway 14 by Selway Fisher and Jay Benford's Happy. One idea mooted was to have the rear panel of the cabin removable. This way the sailor can sit on the aft deck with his legs dangling in the cabin without feeling claustrophobic.