Gemini 105 Review

No catamaran discussion would be complete without a nod to the 34’ Gemini 105M and 105 MC line of catamarans, created by designer Tony Smith. From modest beginnings in 1996, the Gemini 105 has become one of the most popular domestic-built catamarans in the United States, with over 1200 hulls splashed.

Gemini Catamaran History

Originally built in Maryland, the Gemini 105 model began with the 105M (meaning 10.5 meters) in 1995 and then a design change in 2004 to the 105MC, some notable differences being the extended cockpit cover to allow for a full enclosure and a slightly taller mast (while still remaining ICW-friendly). In fact, the “C” in the 105MC stands for “convertible,” likening the cockpit to that of a sports car.

Gemini production moved to FL in 2009 after the 2008 financial meltdown. In 2011, Gemini offered the Limited-Edition Design TouchTM models, whose upgrades included cherry veneer finishes, Corian countertops, and ducted air conditioning. In a partnership with Hunter Marine and a generous buyout from The Catamaran Company, Gemini was able to live on under the direction of Smith’s daughter, Laura building the 105 until 2012. Catalina on the west coast for Florida took over production of the Legacy 35 in 2015, which is still in production today.

A Video By Laura Showing off the Gemini line in 2019 at the Annapolis Boat Show

While the Gemini 105 hasn’t won any official awards, according to SAIL Magazine, “[i]f there ever was a sub-40ft cat that should be included in an imaginary ’Catamaran Hall of Fame,’ it would have to be the Gemini 105.”


Gemini 105 M

The Gemini 105s were designed to be affordable, compact, relatively easy vessels for sailors new to catamarans. In the performance – comfort — cost trifecta, there is a definite favor towards cost, which can equate to quality issues. However, Gemini owners swear by their performance and aspects of comfort.

Let’s see what they highlight.

  1. Narrow Beam. With a beam of 14’, the Gemini can tuck into a standard slip, lowering the cost of ownership and reducing haulout hassles that other catamaran owners sometimes face.
  2. Shallow Draft. With kick-up centerboards and rudders, and outboards (or drive legs) that can raise up, Gemini owners can anchor in as little as 2’ of water. Crowded beach anchorages are seldom an issue for these vessels, which can tuck in well away from other deeper-draft cats and monohulls alike.
  3. Livability. The 3-cabin layout provides both comfort and privacy and the wet head is huge for a small boat. The C-shaped settee converts into a large bed for passages or extra guests. The large, propane-powered refrigerator provides ample space for food and beverages without draining batteries. With 6’ of headroom inside and up to 6’7” of headroom in the cockpit, guests can enjoy the panoramic windows without stooping.
  4. Speed. While the Gemini 105 won’t be breaking any circumnavigation records, for her size, she’s fast—able to achieve 40-50% of wind speeds and the ability to point at about 50 degrees (apparent) to wind. According to Mark Baummer, on SV Argo, the Gemini 105 can easily hit speeds of 8 knots and he regularly logs double-digit speeds. More on why that may be in a moment.
  5. Engine Accessibility. Whether equipped with an outboard or the Westerbeke 30b3 diesel, accessibility is far and above that of most other smaller (and even some larger) catamarans on the market.

Gemini 105 Hull Construction

Gemini 105 On the Hard

The Gemini 105 generally took about 5-7 days to produce, utilizing vinylester resins to bond a barrier coat of 1.5-ounce mat. Next comes two layers of 18 x 15 Cofab mat. The foredeck and cabin top are cored with 1/2″ end-grain balsa, as are cockpit areas in which there are no deck fittings.

The hull-deck joint is a shoebox design bonded with something the designer calls “black poly putty, which cures fast, using a chemical process, rather than an air-dry process. The deck is then secured with stainless steel fasteners on 5″ centers. The joint is covered by a gunwale guard.

Performance Factors

Catamaran designers utilize a broad number of theories in their attempts to achieve performance. For Gemini, this means a 9:1 length to width ratio, with a shallow and fat tear-drop shape intended to increase both speed and load-carrying capacity. Although, with only 18” of bridgedeck clearance, you’ll want to utilize that space sparingly, or risk losing any performance benefits you may have.

Centerboards and sail plan contribute to the cat’s ability to sail closer to the wind than most production catamarans out there.

Is the Gemini 105 a Serious Ocean Cruiser?

SV Slapdash cruising the world

Tony Smith and his son Neil took a Gemini 105 through the northern Atlantic passage from Florida to England on a 23-day trip where they encountered 45-knot winds and 35-foot waves. Neither felt unsafe, but they also swore they would never make the trip again!

SV Tere Hau Nui was a 2003 Gemini 105MC that was sailed across the Pacific to Fiji. Again she was sold via our for sale by owner services in 2012. The new owner sailed her to Australia where she unfortunately dragged onto a rocky shore. The new owner, Brian, bought her back from the insurance company and has fixed her up. He splashed her again in 2020.

SV Slapdash is a 2004 Gemini 105Mc that circumnavigated, albeit with reported frequent stops to perform repairs and modifications. The owner sold by advertising on this website in 2012.

Cruising “celebrity” Carolyn Shearlock (of The Boat Galley fame), owner of SV Barefoot Gal, a Gemini 105M, cruises Florida and the Bahamas, but says she wouldn’t take the vessel offshore.

Mark Baummer, owner of SV Argo, sails his 1999 Gemini 105M in the Chesapeake Bay and offshore to New England, says he would feel comfortable taking the Gemini offshore. He confirms the boat is noisy when underway, saying, “it’s annoying, but you get used to it.” He also noted a great deal of flexibility in the hulls and the main bulkhead pieces working against each other. After a conversation with the designer, he was assured that this is “normal and helps to relieve racking stress on the boat.”

Gemini 105 owner John Grossenbacher says he crossed the Gulf Stream with 18-20 kt NE winds and 4-6′ seas. He reports sailing at 8-9 kts while cooking dinner with a glass of wine sitting on countertop—the classic catamaran marketing brochure image, right?

Like any vessel, it’s really a matter of personal preference, seamanship capability, and the stomach to put up with the chaos that the ocean can throw at you. For my money, I’d stick to coastal cruising on the Gemini. But that’s just me.

The Wish List

Gemini 105 owners love their boats, but there are always things that they wish were different or done better. Here’s what they have to say about that:

  • The Gelcoat – gelcoat crazing is common on the Gemini 105
  • Soft, leaky decks – as you’ll recall, the decks are balsa-cored, so water intrusion can take its toll on these vessels, so be proactive about re-bedding deck hardware, particularly around hatches and stays.
  • Closequarter maneuverability – while Carolyn Shearlock finds the Gemini 105M to perform better in close quarters than her Tayana 47, many find the Gemini, with its single engine, to be a bit squirrely in tight situations.
  • Slightly Under-canvassed – under light winds, the Gemini has trouble, but over 10 knots and she sails beautifully.
  • Forward Visibility – from the cockpit, the view forward is slightly challenging.
  • Centerboard Rot – the original centerboards are prone to rot and worms. Baummer’s centerboards both fractured while on an offshore passage (the boat was fine, but didn’t point as well, as to be expected).
  • Westerbeke 30b3 – this diesel gets mixed reviews and the company that services the drive leg have gone out of business and there is no clear source for parts.Many owners opt to replace the diesel with an outboard.
  • Slamming – there may be no clear answer to this issue given the overall design, but some wish for a wave diverter under the bridgedeck to break up the waves.
  • Inaccessible Wiring and Plumbing – with wiring looms attached to the liner prior to attachment of the liner to the hull, it’s virtually impossible to access without some level of destruction.
Centerboard Rebuild Gemini 105

As these boats are not being produced anymore, these are some things to think about if you plan a refit. Many owners like that the boat is easy to work on (perhaps save the wiring), and at the size of the vessel, those who are handy can do a refit on the (relative) cheap.

The Bottom Line

Described by its designer as “the couple’s catamaran,” the Gemini 105 models are designed to be an introductory catamaran for former mono-hullers. Those who are looking for a coastal-cruising catamaran on a monohull budget might want to give the Gemini 105 some consideration.

River B

By River B

River is a licensed USCG Captain with a lifetime of experience on the water. From the San Francisco Bay to the South Pacific, blue water to clear water, he’s sailed a wide variety of catamarans and crawled around in the bilges of more than he can count. You can follow his misadventures at

3 replies on “Gemini 105 Review”

I need an owners manual for this boat. Specifically the page that lists all the line lengths and guages.

The boat is in Panamá.

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