This page provides our Ocean Alexander MK1 technical specifications.

Poseidon is a 1980 Ocean Alexander Mk1 with 3 staterooms – see image of Ocean Alexander MK1 specs – designed by American boat designer Ed Monk Jr. Ninety two of these boats were made between 1978 and 1983, and Poseidon has hull number 53. From 1984, the Mk1 was superseded by the Mk2.

For those of you who like details, here we go. But if you prefer photos, take a look at the Gallery.

Poseidon has a semi-displacement hull with a deep keel, hard chine, flat stern:

  • Length overall: 50’3’’ (15.25 metres)
  • Length at water line: 45’8’’ (14 metres)
  • Beam: 15’6’’ (4.75 metres)
  • Draft: 4’6’’ (1.4 metres)
  • Air draft: 21’ (6.5 metres) with Radar Arch
  • Displacement: 59,000 lbs (27 tonne) approximately with fuel/water/stores
  • Engines: Twin caterpillar 3208s, diesel, 210HP, naturally aspirated. These are the original engines with approx. 2,300 hrs on each
  • Transmission: Twin Disc, MG502, 2.47:1
  • Propellers: Federal, 4 Blades, 26’’x 20’’ on a 2’’ shaft
  • 1,600 ltr (total) in two interconnected stainless steel tanks per side (replaced/installed by previous owner)
  • Each main engine takes & returns to the same tank (750 ltr available per engine)
  • Two aft tanks not used and assumed not usable
  • Original fuel manifold in place but is only used for the generator and fuel transfer
  • Main 3208s, filtered three times: 1. Racor 900 (30 micron) 2. Racor 500 (10 microns) 3. Engine spin-on (2 microns)
  • Generator, filtered twice: 1. Racor 500 (10 microns) 2. On engine (2 microns)
  • Shore power: 1 x 15 amp input (nominal 3600 watts at 240 volts)
  • Isolation transformer: Victron 3600
  • Shore/generator/off switch to select AC input source

  Generator

  • Kohler 4EFOZ in factory sound shield
  • Nominal 16 amps at 50 Hz/240 volts
  • Fully reconditioned in 2018 with a remote start/stop panel in saloon and approx 50 hours since recondition

Battery #1

  • 8 x Trojan T105 6 volt (225 Ah) deep cycle in series & parallel (nominal 800 Ah at 12 volts)
  • Hydrolink watering system
  • Port engine start battery
  • Generator start battery (default configuration)
  • Charger: Victron 50 amp battery charger (on AC2 circuit)
  • Default configuration has all 12 volt appliances from this bank
  • BMV 702 battery monitor displayed in saloon

Battery #2

  • 10 x Trojan T105 6 volt (225 Ah) deep cycle in series & parallel (nominal 1000 Ah at 12 volts)
  • Hydrolink watering system
  • Starboard engine start battery
  • Inverter/charger: 2 x Victron 3000w/120a/12v configured in parallel with power assist enabled  (AC in from a Shore/Generator selector switch to AC1 & AC2)
  • AC2 only energized if external AC input, e.g. shore power or generator:
    • AC1: power outlets, stove
    • AC2: hot water, secondary battery charger
  • All 240 volt (via inverter) appliances from this bank
  • BMV 702 battery monitor displayed in saloon

We have the battery 1/2/0ff switch in pilot house to select bank for 12 volt house appliances.  Default configuration is Battery #1.

Battery #3

  • N200, 1200 cold cranking amps (CCA)
  • Generator start battery (selected by 1/2/both switch in engine room)
  • 2 x Garmin GPSMAP 5012 Chartplotters (pilothouse & fly bridge) with BlueChart G2 Vision card (East Coast Australia)
  • Airmar SS264/wide/12 degree/200 htz/1kw transducer 
  • Garmin GSD24 sounder 
  • Garmin GPS 19X antenna
  • Robertson AP100 autopilot (unused)
  • Robertson R 100 rudder indictor (used)
  • VHF: Standard Horizon GX2000
  • Aft tank: 1,000 ltr (approx.) in three interconnected stainless steel tanks
  • Mid tank: 500 ltr (approx.) in one stainless steel tank
  • Tank selector in engine room
  • Accumulator tank: Jabsco 22 ltr with integrated Jabsco 3.5 (13 ltr/minute) Parmax pump
  • Lofrans (Falkon) 1700w with 100 metres of G40, 10mm chain (ISO 4565)
  • Anchor 1: Manson Supreme 80 lbs
  • Anchor 2: CQR (Genuine) 75 lbs (spare)
  • Anchor 3: Fortress 55 (spare)
  • Raritan Marine Elegance electric fresh-water toilet, with remote/smart toilet flush control
  • 2 x 80 ltr interconnected PVC holding tanks (for the above)
  • TMC salt-water electric toilet in laundry (not used)