AF4 is a simple low powered cuddy cruiser intended for protected waters. Kilburn Adams of St. Louis brought a boat similar in spirit to AF4 to our Midwest Messabouts and it was easy to see what a good idea this is. Kiburn's boat was a modified Sturdee Amesbury power dory with a small cuddy added and a new 4 stroke Yamaha 10. He thought the empty boat weighed about 600 pounds ready to go. It planed quite well with two men on board at about 13 knots. He made a 60 mile trip on the Mississippi (above the Alton dam where the current is small) burning about 4 gallons of fuel. It's quiet and cheap to operate. It's a good idea now that smaller 4 stroke motors are more common.
Here is an AF4 by Barry Targan. I think he is using a new 8 hp 4 cycle.
AF4 is supposed to do about the same job. Its simple hull shape won't handle rough going like the dory, but it's very easy to build and roomier. This boat has an open bow well for anchors and junk. The cabin is 8' long and 3' deep and 4' wide for minimal camping. It should be comfy for one and snug for two. it has a slot top to allow stand up boating in good weather. You cover it with a snap on fabric piece in the rain and cold. The cockpit is a full 6' long and 4' wide and totally open. You could lounge there too with a folding chaise. Aft of the cockpit is a draining motor well which will take the standard 6 gallon fuel tank and then some.
For power I used to say 10 horsepower maximum but now I would say 15. My boat has gained gear and weight over the past three years and is more comfortable with the extra power. A light AF4 planes with an old Sears 7-1/2 horse (single cylinder, air cooled, for $50 at a yard sale) as you can see here:
Here is John Bell & co. in his AF4. I think John is using a 20 hp four stroke having tested the boat first with 25 hp and found it too much.
Here is one by Rhett Davis at the last Rend Lake meet.
Bayard Cook built this delux AF4 in Florida:
AF4 uses the simplest nail and glue construction. It takes five sheets of 1/4" plywood and four sheets of 1/2" plywood.
There is also a shorter 15' version called AF4Breve, the prototype shown here built by Bruce Given. There is also a somewhat larger version called, logically, the AF4Grande