Design for Recreational Rowing – by Allan Witt

[vc_row][vc_column][vc_column_text]The Australian recreational rowing movement has its origins in Tasmanian design. It received a nudge along from a design competition at the 2007 Australian Wooden Boat Festival and the release of Derwent Skiff kits. There are some design challenges we still need to meet to grow the movement:

• Lighter, easier car-topper boats
• More DIY and built-for-you options (suiting both enthusiasts and time-challenged people)
• Wood and composite options to satisfy the two main preferences
• Coastal rowing competition capability

We want to see more people having better access to do things like a regular Saturday morning row to a coffee shop in a skiff capable of open water rowing, or rowing in conditions where you could not safely use a shell (rowing scull) designed for still water racing.[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_single_image image=”1024″ img_size=”medium” add_caption=”yes” alignment=”center”][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]Classic Clinker Hull

The core of Australian recreational rowing is the Derwent Skiff class, in its 5.5m (18’) classic clinker form. That’s the red boat in the photo above. These are small rowing boats with a good and well-proven balance between speed and stability. The key is the narrow waterline, for satisfying runs between strokes, coupled with generous reserve buoyancy so that the boat will sit you up without needing to rely on the oars (see drawing below). That is important if you are on the water by yourself.

The light-weight version of the classic clinker hull uses a monocoque structure to replace traditional row boat components, but without compromising strength and rigidity.[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_single_image image=”1027″ img_size=”full” alignment=”center”][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]Round Bilged Variant

The round-bilged form allows for exquisitely made strip planked and cold moulded boats as well as moulded composite ones (glass/core/glass sandwich).   Composite hulls allow for more manageable home build projects like adding a plywood deck and cockpit. There is the opportunity for full composite construction for those who want it.[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_single_image image=”1028″ img_size=”full” alignment=”center”][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]Design Considerations

A section comparison graphically shows the same trade-off between speed and stability.[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_single_image image=”1029″ alignment=”center”][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]The tracking ability of the slightly flatter hull won’t be an issue as it will have a retractable rudder as a skeg. That’s better for beach use without the annoyance of a traditional skeg dragging on the sand. It also allows for a steerable rudder coupled with a small centre-board and sail. More options, more fun.

The Derwent Skiff’s designed position in the water (nominal 90kg rower), provides comfortable rowing positions for heavier and lighter people. The lighter boat’s displacement has been adjusted for the same load carrying characteristics.

Care was taken to avoid hollow waterlines at the bow (diminishing any performance gain from the changed profile) and to avoid moving the longitudinal centre of buoyancy (rowing position) significantly. The change was held to 13mm.

The Derwent Skiff catches waves well, which is a bit of fun and handy for coastal rowing. The rocker and aft sections remain similar.

The new boats are self-draining via a ‘wet’ aft deck. This reduces expedition stowage, but for coastal rowing, the value of having green water simply flowing straight out the stern is valuable.

Derwent Skiff laminated riggers have become a bit of a trade mark for the class and have the same rigidity as you would expect in a racing rig. As we did not wish to lose that design element, the same curve is retained but on separable port and starboard riggers. A quick-release mechanism, like that used on Derwent Raiders, lets them go in the boot of the car, making one-person car topping and storage even easier.

Cutting the weight comes from comes from using a light-weight monocoque structure (borrowing an automotive term). Gone are the traditional keel, gunwales and the need for a big beam across the boat to take the rowing stresses. Every detail received attention for weight savings.

Derwent Raiders are growing in popularity for recreational rowing, too. Despite having more stability (enough to carry a 5 sqm sail), at recreational cruising speeds they keep up with Derwent Skiffs. They have received the same round-bilged treatment to create more options and access too.

Happy rowing![/vc_column_text][vc_column_text]For more on Allan Witt’s lightweight boat designs, visit:  rowandsail.com.au[/vc_column_text][/vc_column][/vc_row]