Nickyp:
The term "easily driven" usually describes a displacement hull shape that requires very little power to achieve hull speed. Long and narrow with rounded bilges is one of the most easily driven shapes. An example is the yacht
Olympia (92'L x 18'B x ~8' Draft x 125 tons) that cruises at 9.5 knots on twin 165 hp diesels.
I'm guessing your question is really geared more toward
fuel efficiency at planing speeds and you're wondering which 31' hull on the market offers the most efficient operation. I don't think there's a specific answer to that question without knowing a lot more about what you expect:
- How fast do you want to run?
- What gear and other weight will you have aboard ?
- Will you be running inshore or offshore and in what conditions?
- What do you require in terms of head sea and down sea handling and performance?
- What range do you require?
- How do you define "easily driven"?
With those answers, somebody can probably narrow your choices down for you.
On the subject of building light
Pros:
- Gain speed for a given power
- Gain fuel economy for a given speed
- Gain load capacity for a given displacement
Cons:
- Generally more expensive in labor and material costs.
- Light construction methods can result in less durable structures that require more maintenance and repair
- Light construction can worsen the behavior of a hull in certain conditions if the design was not intended for it