: . . .But it should come out
: light enough to easily load on the roof. Hopefully the 16' boat will be
: light enough my niece will be able to handle it by herself.

OK, if your primay reason for building a light boat is to get it on top of your car, solve the car topping problem--don't change it into a boatbuilding problem.

A few ideas for getting the boat on top of the car with greater ease:

1) There are commercially available, spring-loaded boat lifts which do the lifting for you.

2) change the way you load the boat. Just put up one end at a time. You lift only BOUT half the weight at any given time. A longer boat may be easier to handle with this method of loading than a shorter one. Typically a roof rack has two bars, one in front and the other in back. To make the loading process easier,
you cna have one of those bars extend a few feet over the side of the car. Then you have a straight lift, to get one end of the boat on that extended bar. You then lift the other end of the boat and maneuver it onto the other bar. Finally, you slide the boat off of the bar extension, getting it centered in its proper place. You can then remove the extended part of that bar, so it doesn't interfere with your driving.

An electric winch (Harbor Freight currently sells one for about $60) can be fitted to the roof rack. That, along with a sling can pull up your boat, and you won't do any lifting.

Once the boat is off the car, many people use a wheeled cart, or dolly to get the boat from the car to the water.

Sure, it is fast to grab a boat and hike to the water's edge, but for those who don't have the physical stamina, dollies and lifts make boating possible--and for others these devices make boating more enjoyable.

The point is this. Design your boat for its on the water characteristics. YOu have enough trade-offs and compromises to deal with there. You don't need to factor in more variables. Whatever problems you may create for handling the boat on land can be easily worked around.

A boat which is significantly lighter in weight than others of similar design will probably not last as long. people who are racing boats may want a lighter boat, and be willing to pay for it in greater costs for high tech materials, and shorter life. For a general purpose boat, though, I'd suggest building to specs and getting something with a longer life.

PGJ