Boating New Zealand — February 2018

92 Boating New Zealand

He’d been away two years when he came back to New

Zealand and took a spar-making job with Fosters, then owned

by John Street. “John was a helluva good boss, he let me build a

new mast there after hours.”

The alloy mast Sharpie built was for a little plywood keeler

he’d bought, a double-ended 8.5m Daydream class, designed

by Australian sailor Peter Fletcher. Sharpie left Fosters to set

up a mast-making division for Stewart Scott’s Marine Metal

Fabrications, which he ran for several years.

After selling his keeler to his father, Sharpie commissioned

Dave Jackson to build an Alan Wright Marauder 8.4m. As was

common then, Sharpie and his friend Ken Moir finished off

the Marauder’s bare hull and decks and launched what became

Kasmic – she became a very successful racer.

Conceptually, the Floating Dock’s fairly simple. Twin, 13.7m long

longitudinal cylinders support a grated raft floor 9m wide. Six, 3.4m high

vertical cylinders are mounted on the longitudinal cylinders to give three

compartments each side.

Similar to a submarine’s pressure hull, each compartment has large

holes in its bottom, and there are intake and outlet air pipes in the

top of each vertical cylinder. To sink the dock, the air is bled from the

top of each cylinder, which then allows water to enter into the lower

compartment to flood the raft floor.

To use the dock, it’s flooded deep enough in the water to suit the

boat’s draft. The boat enters the dock and is held centrally by hydraulic

arms either side. Compressed air is fed into the top of each cylinder

forcing water out of the bottom of the six compartments until the

buoyancy counters the boat’s weight and the grated floor reaches the

surface. It has a maximum 20-ton payload.

Each cylinder is individually controlled, so the raft floor can be

levelled sideways, as well as fore and aft. Fore and aft tilt is set to suit

each boat. For example, launches are generally raised slightly bow high

to ensure their exhaust pipe(s) drain aft. As boats sit on their keels, there’s

no stress from travel lift strops, ideal for classic keelers, nor is there the

risk of damaging speed and depth transducers.

The lifting process takes three to five minutes.

When water-blasting the bottom, a tank down the middle of the raft

floor collects the water, which is then fed through a sand filter to strain

the contaminants. The clean water is then pumped into the Auckland

City Stormwater system. Periodically, the sand filter is raked over and the

heavy paint particles bagged and disposed of.

As well as water-blasting boat bottoms, The Floating Dock is

regularly used for surveys, anode replacements, propeller servicing and

overnight/weekend antifouling applications.

THE FLOATING DOCK