Flybridge Cruiser

Overview

A flybridge cruiser is a planing or semi-displacement motor yacht laid out around two helm stations. The lower station sits in the enclosed saloon for poor weather and night running, and a second open station sits on the flybridge, an upper deck built on the coachroof above the main cabin. The flybridge gives the skipper a high, all-round view for close-quarters handling and a large open social area when the boat is at anchor. The example here is roughly 16 m, driven by twin shaft-drive diesels for a 22 kn cruise and a 30 kn top end.

The boat is organised into a Hull & Superstructure that carries everything, the Flybridge upper deck, the Main Deck Saloon & Cockpit saloon and cockpit, a pair of Marine Diesel Engine diesels each with its own Gearbox & Shaft Line, a shared Steering System system, plus tankage, electrical, navigation, accommodation and deck-hardware groups. Twin engines on separate shafts let the skipper turn the boat almost within its own length by running one ahead and the other astern, and they leave the boat manoeuvrable if one engine stops.

Hull and superstructure

The Hull Shell is a cored GRP laminate moulded as a deep-vee planing bottom, with a fine forefoot to cut head seas and flatter sections aft to lift the hull onto the plane. Foam-cored Hull Stringer members run fore and aft to stiffen the bottom against slamming loads, and bonded Watertight Bulkhead panels divide the hull into watertight compartments so that flooding in one space does not spread. The Transom is reinforced where the engines, shaft brackets and rudders feed their loads into the structure. The cabin and coachroof are a separate Superstructure Moulding moulding bonded to the deck, with bonded tempered glass making up the windscreen and side windows.

Flybridge and helm

The defining feature is the upper deck. The Flybridge carries its own Flybridge Console with a Multifunction Display, a Steering Wheel and one Engine Control Head per engine, so the boat can be driven entirely from up top. Both stations share one set of machinery: the wheel on each console turns a Hydraulic Helm Pump that feeds the same hydraulic steering circuit, and both sets of control heads command the same electronic engine throttles and gears. A moulded Hardtop on four stainless posts shades the upper helm and carries the radar scanner, with a Bimini Extension canvas extension over the aft seating. A moulded Flybridge Ladder links the flybridge to the cockpit. The lower Lower Helm Console in the saloon repeats the same display, wheel and controls for running in bad weather.

Propulsion

Each Marine Diesel Engine is a turbocharged common-rail marine diesel. The cast-iron Engine Block carries wet liners and a forged Crankshaft, and the Turbocharger feeds a seawater-cooled Charge-Air Aftercooler to pack more air into the cylinders. The Fuel System runs common-rail injection with a water-separating Fuel Filter / Separator ahead of the high-pressure pump. Cooling is a closed circuit: a belt-driven Raw-Water Pump draws seawater through the boat's skin fitting and pumps it through a Heat Exchanger that cools the engine's own coolant, after which the warm seawater is dumped overboard with the exhaust.

Driveline and steering

Behind each engine sits a Marine Gearbox, a reversing reduction box that drops engine speed to the slow, high-torque rotation a propeller needs and selects ahead, neutral or astern. Its output turns a stainless Propeller Shaft that passes through the hull in a Stern Tube & Seal sealed by a dripless shaft seal and supported by a cast P-Bracket just ahead of the five-blade Propeller. A balanced Rudder behind each propeller steers by deflecting the propeller race. Both rudders are linked by a Rudder Tie Bar and driven by twin Steering Cylinder rams, so the helm pumps at either station move them together. The autopilot drives the same rams through its own Autopilot Pump.

Systems and electronics

Power comes from house and start battery banks charged by a belt-driven Alternator on each engine. At anchor a sound-shielded Diesel Genset and an Inverter / Charger supply mains AC, and a Shore Power Inlet takes dockside power. Diesel sits in two baffled Diesel Fuel Tank bunkers split port and starboard to keep the boat in trim, alongside fresh-water and blackwater tanks. The navigation suite mounts a Radar Scanner on the hardtop and feeds position and heading into the Autopilot Computer, with a VHF Radio radio and an AIS Transponder transponder for traffic and communications.

Accommodation

Below the main deck the boat sleeps four in two cabins, each with a Berth and a wardrobe, served by two Marine Head compartments with showers and a Galley with a stove, refrigerator and sink. On deck the cockpit opens through a sliding door to the saloon, and aft the Swim Platform and a telescopic Passerelle handle boarding and stern-to mooring. An electric Anchor Windlass handles the anchor.