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Copyright 2001-2021 inclusive   McGowan Marine Design, Inc.

The Running Tide 43 is a big sister to Evergreen - and though far flashier and able than her sibling still sports the same biplane rig as the smaller cat. 

Worked to this stage for a very experienced Australian sailor and well-known nautical and historical author, Running Tide 43 is intended to be a comfortable live-aboard for two with room for a few visitors for a few weeks.  The boat is designed to be comfortable, easy to sail, and to have an excellent turn of speed.

The preliminary modelling showed a more traditional cockpit layout, but it turned out to be wasteful of space with the two-wheel setup.  Bruce foils were looked at as well -for performance and how they were out of the way when raised.

Running Tide 43 - a Biplane-Rigged Catamaran

Propulsion is twin 30hp diesels with saildrives and folding props.

I’m trying out a mid-vessel master cabin aft - in the middle of the lower living deck and overhanging the aft main beam - and the space and light is encouraging.


LOD - 43.1’ (13.1m)

LWL - 42.6’ (12.98’)

Beam - 21’ (6.4m)

Draught - 4’ (1.22m)

Displacement - 16,000 lbs

Working Sail - 1,200 sq. ft. (111.5m  )

Bruce# - 1.38

After much back and forth we settled on a high-chine design, with winged keels for performance and shallow draught.  The keels are bolted inside low cases so they may be very fine-sectioned and easily reparable.  The cases are under the cabin sole. 

There is no chine on the inboard side of each hull - to improve stair layout to the sleeping cabins and for construction simplicity.

Construction is mostly balsa cored panels with E-glass and the lower, round hull is strip-planked red cedar.

The large house tapers in width forward, to fit between the masts - which is good for halyard leads, and has a unique convex roof that’s reminiscent of a Mercedes 230 SL Pagoda Top - a design we both like.

Preliminary Design

Preliminary rig design shows simple non-rotating carbon fibre masts and wishbone booms with fat-top mains.  A reacher or genoa may be set flying for reaching and running. The sail area and Bruce number are encouraging. 

The mainsails are going through an evolution - to sleeved sails, but losing the wishbones to two internal ‘spars’ (big angled battens really, at the head and foot of the sail) that connect to mast sleeves. The trick to this working is in the design of the pipes, or tall, thin mast hoops that not only connect the sail to the battens, but allow for halyards and running backstays off the top two - for reaching sails to be set flying.  I’m hoping this sail, that I’m calling a Fundy Rig (for my favourite body of  water, the Bay of Fundy) will improve the aerodynamics over a non-sleeved cat rig, will be simple and reliable, and allow for the single-point sheeting required for this boat.



Running Tide 43 Movie


Each hull has a Queen-size berth aft, excellent storage, and a 3-piece washroom. 

The Saloon is enormous, and with a skylight and wrap-around windows is very bright.  The galley is aft with dining forward of this - under the skylight - and the living space wraps around the forward end of the saloon.  One forward corner is devoted to office space.  Access to the lower living deck (aft cockpit) is through a door to starboard of the galley.

By moving the cockpit upward, an outside galley with good storage is located below.  Nice backrests and a bimini (not shown) would ensure good comfort in the tropics. The culturally-required barbie is located at the aft end of the lower living deck, and there is cushioned wrap-around seating over the berths in the sleeping cabins.


“Fundy Rig”

Running Tide 43 Stern View

The open afterdecks are ideal for access to the water, the tender (slung off the roof-hung davits), or to the dock.


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