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Seller's Description

Fresh Water Diesel Catamaran - Solar Panels - 3 Cabins - 3 New Batteries - Dinghy Included - Rare Cruising Catamaran

For over 27 years and over 1000 deliveries, the Gemini 105Mc still remains one of the most proven and popular catamarans ever built. Her sailing performance is legendary yet still manages to surprise unsuspecting newcomers.

The accommodations are spacious, light, and airy so that the term “down below” just doesn’t apply. The deck layout and rig offers a stable, safe, and well-reasoned platform for whatever comes your way.

And the ingenuity of lifting centerboards and kick-up rudders will have you sailing through less than 2’ of water. All this and more at 33’ 6” length and a 14’ beam that can moor in a standard slip or truck across the country.

Currently located on Lake Champlain (US)

Equipment: Dimensions: LOA: 33’6’’ Beam: 14’ Maximum Draft: 5’ 5’’ Dry Weight: 9000lbs

Engine: Type: Inboard Make: Westerbeke Model: 27HP Diesel Drive: Hours: 1430hrs

Tankage: Fuel: 43g Water: 60g Holding Tank: 18g

Electrical/Equipment: GPS chart plotter Garmin 192C Raymarine repeater at nav station, measuring wind, speed and depth Weather vane, compass and depth sounder Raymarine autopilot Radar reflector Davis Echomaster Two VHF radio (1 fix and 1 portable) Sony stereo AM/FM CD with bluetooth and four speakers (2 in cockpit and 2 interior) CO2 Detector Fuel gauges AC & DC electrical outlets; one outlet at helm All electric lighting changed to LED 12-volt DC electrical system with breaker panel Dock connection 30 amp. Marinco 30 amp alternator 1750 watts charger/inverter Xpower 1 starting battery and 4 house batteries Two solar panels SolarWord 140W each with voltage reading control Battery charger Iota 45 amp Battery monitor system Cockpit red LED lighting Electric ventilators in all rooms

Sails and Rigging: Roller-furling 150% jib and screecher Lewmar 3 self-tailing winches, 2 at the helm station and 1 at the mast 3 winches handles Upgraded Schaefer main-sheet traveler system Lazy bag and Lazy-jack mainsail cover Bridge clearance: 47 ft Mast height: 39 ft

Hull and Cockpit: Walk-through transom with two swim ladders Shoal draft keel with retractable dagger-boards and kick-up rudders Bilge pumps servicing both hulls and shower Hot and cold fresh water shower on transom Stern hammock 2 places bench at the helm station Full canvas enclosure - both Eisenglass and screen sets Folding cockpit table

Deck Equipment: Non-skid decks throughout 2 anchors Kobra2 and Bruce with 100 ft of 1/2 inch chain and 100 ft rode Electric windlass Quick Crystal 600 with handeld remote Stainless steel dinghy davit system, includes hammock, wake board speakers and two 140W each solar panel

Miscellaneous: Five black fenders 2 boat hooks 1 pick-up pole 1 life saver with rode BBQ 2 fire extinguishers - SOS flag Emergency gun Horn Dinghy, inflatable Mercury 2009, 280 model Dynamic 99 (3 1) Mercury Motor 2008, 6HP



Tony Smith
Performance Cruising
# Built
Twin Centerboard


Length Overall
33 11 / 10.4 m
Waterline Length
31 9 / 9.7 m
14 0 / 4.3 m
1 6 / 0.5 m 4 11 / 1.5 m
8,000 lb / 3,629 kg

Rig and Sails

Reported Sail Area
690′² / 64.1 m²
Total Sail Area
Sail Area
Air Draft
Sail Area
Forestay Length

Auxilary Power

Fuel Type
Fuel Capacity
36 gal / 136 l
Engine Hours


Water Capacity
60 gal / 227 l
Holding Tank Capacity


Hull Speed
10.8 kn
Classic: 7.55 kn

Hull Speed

The theoretical maximum speed that a displacement hull can move efficiently through the water is determined by it's waterline length and displacement. It may be unable to reach this speed if the boat is underpowered or heavily loaded, though it may exceed this speed given enough power. Read more.


Classic hull speed formula:

Hull Speed = 1.34 x √LWL

A more accurate formula devised by Dave Gerr in The Propeller Handbook replaces the Speed/Length ratio constant of 1.34 with a calculation based on the Displacement/Length ratio.

Max Speed/Length ratio = 8.26 ÷ Displacement/Length ratio.311
Hull Speed = Max Speed/Length ratio x √LWL

10.75 knots
Classic formula: 7.55 knots
Sail Area/Displacement
>20: high performance

Sail Area / Displacement Ratio

A measure of the power of the sails relative to the weight of the boat. The higher the number, the higher the performance, but the harder the boat will be to handle. This ratio is a "non-dimensional" value that facilitates comparisons between boats of different types and sizes. Read more.


SA/D = SA ÷ (D ÷ 64)2/3

  • SA: Sail area in square feet, derived by adding the mainsail area to 100% of the foretriangle area (the lateral area above the deck between the mast and the forestay).
  • D: Displacement in pounds.
<16: under powered
16-20: good performance
>20: high performance

Ballast / Displacement Ratio

A measure of the stability of a boat's hull that suggests how well a monohull will stand up to its sails. The ballast displacement ratio indicates how much of the weight of a boat is placed for maximum stability against capsizing and is an indicator of stiffness and resistance to capsize.


Ballast / Displacement * 100

<40: less stiff, less powerful
>40: stiffer, more powerful
100-200: light

Displacement / Length Ratio

A measure of the weight of the boat relative to it's length at the waterline. The higher a boat’s D/L ratio, the more easily it will carry a load and the more comfortable its motion will be. The lower a boat's ratio is, the less power it takes to drive the boat to its nominal hull speed or beyond. Read more.


D/L = (D ÷ 2240) ÷ (0.01 x LWL)³

  • D: Displacement of the boat in pounds.
  • LWL: Waterline length in feet
<100: ultralight
100-200: light
200-300: moderate
300-400: heavy
>400: very heavy
Comfort Ratio
<20: lightweight racing boat

Comfort Ratio

This ratio assess how quickly and abruptly a boat’s hull reacts to waves in a significant seaway, these being the elements of a boat’s motion most likely to cause seasickness. Read more.


Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam1.33)

  • D: Displacement of the boat in pounds
  • LWL: Waterline length in feet
  • LOA: Length overall in feet
  • Beam: Width of boat at the widest point in feet
<20: lightweight racing boat
20-30: coastal cruiser
30-40: moderate bluewater cruising boat
40-50: heavy bluewater boat
>50: extremely heavy bluewater boat
Capsize Screening
>2.0: better suited for coastal cruising

Capsize Screening Formula

This formula attempts to indicate whether a given boat might be too wide and light to readily right itself after being overturned in extreme conditions. Read more.


CSV = Beam ÷ ³√(D / 64)

  • Beam: Width of boat at the widest point in feet
  • D: Displacement of the boat in pounds
<2: better suited for ocean passages
>2: better suited for coastal cruising


GEMINI 105MC is a development of the 105M with a number of interior updates. Most visibly, however, the cockpit of the 105Mc can be temporarily enclosed with either canvas or solid panels.

This listing is presented by SailboatListings.com. Visit their website for more information or to contact the seller.

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