Ultimate Sailboats Antrim 27: Bob Perry Design Review

USI's Antrim 27 is a Tough-to-beat sportboat with clever layout

16th July 2001.
By Bob Perry

img7683Jim Antrim is probably best known for his radical trimarans that have been ripping up the San Francisco racing scene for the past five years. Jim is also involved with cats and has done extensive engineering on a number of high-tech projects for other designers, including myself. The Antrim 27 lets us see Jim’s talents applied to a boat that is (almost) normal.

Attacking the sportboat market, Ultimate Sailboats International of Santa Cruz, California, asked Jim to come up with an ocean-capable 27-footer that would be a perfect boat for the performance enthusiast and would offer better stability than its competitors. The hull form features a fine and very slightly hollow entry. There is considerably more fullness to the bow above the waterline than is currently typical in order to keep the boat riding high and dry in ocean wave conditions. The fine, slab-sided bows we often see today can easily bury themselves into the back of the next wave. The prismatic coefficient of .56 indicates a full-ended shape. Beam is kept at 9 feet, 3 inches to make trailering easy. The factory weight of 2,600 pounds and the retractable fin keel also help with trailering. The D/L of this design is 86.64.

img7682The fin-up draft is 3 feet, 4 inches. The fin is a cored carbon-fiber blade with a 1,050-pound lead bulb on the bottom. It is fixed in the down position for sailing. The bulb has a small beaver-tail trailing edge. The thickness ratio of the fin is about 13 percent. The rudder features a “gudgeonless,” patented-type attachment to the transom that is neater and cleaner than the typical metal gudgeon type. It also allows the rudder to be attached more snugly against the transom. The balance area on the rudder is 17 percent.

The boat has a big, dinghy-style rig with an adjustable headstay. The jib is fitted over the headstay with a sleeve. The spreaders are swept aft to a 28-degree angle at the deck, eliminating the need for a backstay. The mast is designed to bend above the hounds for depowering the mainsail in a breeze. The SA/D is 29.95, using the I, J, E and P for sail area. Jim has designed a patented swiveling bowsprit that is controlled from the cockpit by a line-drive unit. This is a safer and more versatile way of attaching a retractable bowsprit, as opposed to the internal tube-type mounting. There is a recessed groove in the foredeck to control the travel of the aft end of the tube; the forward end is clamped in a fitting that is like an oarlock.

img7681There is usually not much to say about the interiors of sportboats, but Antrim has devised a very clever and workable layout for this little rocket. He integrated the structure required to support the keel trunk with the interior components. It’s a sit-down layout and you will have to scoot around on your rear, but it does work. You can even close off the head area for some privacy. I’m not saying that this is a cruising boat, but you could cruise with it. My cruising pals Paul and Laura would consider this luxurious compared to their current Ultimate 20.

We see a lot of these sportboats entering the market today. Competition between them is keen; the Antrim 27 will have to shine in all areas to capture its share of the market. Considering the work that the Ultimate group has done with their other models, I think the builder and designer combination of Ultimate and Antrim will be tough to beat. This is one boat I really want to test sail.

Tough-to-beat performer with clever layout.

img7680Boat Specifications

LOA 27’10″
LWL 23’9″
Beam 9’3″;
Draft 3’4″ keel up 6′ keel down
Displacement 2,600 lbs.
Ballast 1,050 lbs.
Sail Area 354 sq. ft.
SA/D 29.95
D/L 86.64
L/B 3.00
Auxiliary 5-horsepower outboard (optional 12-horsepower inboard Honda R-Drive available in April)
Fuel 5 gals.
Water 25 gals. (in 5-gal. containers).

Ultimate Sailboats
PO Box 8421
Santa Cruz, CA 95061
Phone: (831) 763-2720
Fax: (831) 763-2730
ultimatesailboats.com

 

SAILINGlogo-115This story originally appeared in Sailing Magazine, and is republished here by permission. Subscribe to Sailing.

 


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