I was approached by representatives from the West Australian naval cadets to help find a suitable design for their cadets to learn to row and sail and seamanship.

They were looking for a design that would be used primarily for rowing, but that could also be sailed, the boats would need to be able to carry a crew of up to six teenagers,  and be safe to row and sail in a variety of conditions. 

I approached Francois Vivier and this is the boat that he has designed and which we are now building.

This design is intended for use with teenage cadets but we also see it as a family sailing and rowing boat that can be rowed by one, two three or four people, as well as having an easily struck rig for sailing.

The following is Francois' description of the new design, we have commenced building the first of four boats to this design, and pictures and progress reports can be viewed on the blog. 

Introduction

The design intend is make a “sail and oar” dinghy intended for youth organisations, like sea scouts or cadets. Therefore the normal crew is 5 with 4 rowers (two rowers in the centre thwart side by side, one forward and one aft.). The maximum crew is 6. The design is as simple as possible, in order to minimize the budget and required construction labour time. Plywood is extensively used and parts are CNC cut. It is possible to build the boat as a rowing boat only.

The hull lines are drawn to get a good compromise under oars and under sail, with a narrow waterline beam and a V shaped transom.

Main characteristics

Hull length : 5.7 m
Waterline length : 5.3 m
Breadth : 1.8 m
Waterline breadth : 1.34 m
Sail area : 20+ 12.5 m2
Weight estimate as a row boat : 170 kg
Weight estimate as a sail boat, ready to sail : 230 kg
Buoyancy volume : 200 + 175 litres
Compliance to ISO 12217 for buoyancy and stability. The boat may be righted and emptied by the crew.

Due to the 3 thwart arrangement, a cat-boat or sloop rig leads to a more complicate structure as the masts was to be stepped between thwarts (see sketch). Therefore, we have preferred a lug yawl rig. This rig allows to keep the mizzen up when rowing to stabilize the boat. The mizzen mast is stepped in a box integrated into the transom (and drained through the transom). The main mast is stepped just aft of the fore buoyancy compartment. The main sail has no boom. The mast may be stowed inside the hull when rowing (see sketch).

Construction

Clinker planking. 9 mm plywood for sole and garboard. 6 mm plywood for upper planking to save weight. Sole and garboards sheathed outside for better abrasion resistance. Frames made of 18 mm plywood with a timber strip glued on the visible edge. End bulkhead and decks 9 mm. Simple pivoting centreboard case. Side seats and rowing thwarts soft wood 22 mm. Watertight buoyancy compartment at ends with access by dinghy type hatches.

A building frame is built from CNC cut ordinary plywood parts which are easily assembled (criss-crossed) and make supports for frames, bulkheads, transom and stem.

The rudder is non pivoting. A small rope coming from the lower pintle allows to put down the rudder easily at sea.
The transom allows to fit an outboard, as it could be useful to have one boat in a fleet with an outboard to insure safety.

No floorboards. The sole (inside) is painted with anti-slip paint. However, simple floorboards may be added.
Oars have all the same size, 3 m long, and may be made by the sea scouts with laminated plywood blades.