What makes the Shoalsailer design revolutionary?

 

The Shoalsailer is a revolutionary breakthrough because it provides exhilarating sailing (especially to weather) while drawing only 30". The conventional wisdom for the past century has been that the ability of a sailboat to sail in the general direction of the wind is predicated on the depth of the keel. In essence, the deeper the keel, the better the windward performance. The penalty for this improvement in sailing characteristics is the inability to sail the boat to weather in shallow water. The Shoalsailer is the first design, probably since the Viking dragon ships, that achieves performance to weather by the shape of the hull rather than by the depth of the keel.

 

What is different about the Shoalsailer from other "shoal draft" boats?

 

The Shoalsailer draws 30" with NO BOARDS. Therefore, the major accomplishment of the Shoalsailer is "sailing draft". What is the point of having a 3 foot "shoal draft" sailboat that must lower a centerboard or daggerboard to over 6 or 7 feet in order to actually sail?

 

How does the Shoalsailer achieve such good performance sailing to windward with such shallow draft?

 

The totally unique hull shape of the U.S. patented Shoalsailer provides stability through its beam, and achieves lift to weather by the accelerated laminar flow of water rushing past the leeward side of the hull. The fine entry of the Shoalsailer's bow helps define the direction of the water as it moves under the hull. Per the Bernoulli Principle, a sausage-shaped torpedo of aerated water is moved along the keel. This vortex of aerated water pressing against the hull and long shallow keel resists the leeway pressure on the hull created by the sails.

 

How well does the Shoalsailer sail to windward?

 

The Shoalsailer can sail 35 degrees relative to the apparent wind. In 10 knots of true wind, the Shoalsailer will sail to windward at 6 knots. At 14 knots it will sail to windward at 7 knots. And, at all times going to weather the slight angle of heel is only 8 to 12 degrees, similar to a multi-hull. At 5 degrees angle of heel, the wetted surface is dramatically reduced as the hull lifts out of the water and the Shoalsailer rides on the bulge along the center of the hull. The helm balance of the Shoalsailer is exceptional, with no weather helm pressure when sailing to windward. The Shoalsailer has an extraordinary ability to climb to windward without slipping sideways, and will not pound in a head sea. The Shoalsailer has sailing characteristics comparable to a fixed keel 32' monohull with 5' draft, and much better than those of a 32' catamaran.

 

How does the Shoalsailer sail off the wind?

 

The long shallow keel of the Shoalsailer gives it great tracking characteristics sailing down wind. In very light air, 5 to 8 knots true, an asymmetrical spinnaker provides significantly more sail area to offset the wetted surface of the Shoalsailer's beam that is carried well aft. Compared to a fin keel/spade rudder hull which acquire great attention to the helm when sailing down wind, the Shoalsailer is a joy to sail off the wind.

 

What is the leeway factor or sideslip on the Shoalsailer?

 

The Shoalsailer has approximately 7 degrees of average leeway over wind and sea conditions ranging from 8 knots to 22 knots, not quite as good as the J30 but better than the C&C. All boats sailing to weather demonstrate some leeway from the side forces of the wind on the hull. Typically, a racing yacht with a very deep keel will experience about 3-5 degrees of leeway, a fin keel moderate draft vessel will see about 6-8 degrees, and a centerboard catboat or cruising catamaran will measure about 10-12 degrees of sideslip.

 

How does a Shoalsailer sail compared to a catamaran?

 

The Shoalsailer sails better with 30 inch draft than a 35 foot monohull or catamaran drawing over 6 feet. In spite of advertising claims, most cruising catamarans do not sail very well to weather or tack easily. Like "shoal draft" monohulls using a centerboard or daggerboards, 30 to 35 foot catamarans have an actual "sailing draft," (with board down) of well over 6 feet.

 

Can the Shoalsailer really be beached?

 

The Shoalsailer hull laminate schedule was specifically engineered for beaching. There is a layer of incredibly strong and abrasion resistant uni-directional Kevlar/glass hybrid that runs down the bow all the way to the lead keel. The composite sandwich core hull utilizes 3/4" linear closed cell foam through-out to stiffen the entire structure without adding a lot of weight. The triaxial laminates on either side of the core provide amazing strength. While this hull will be impenetrable in normal beaching situations, in the case of a high speed grounding on rocks, a watertight crash compartment under the V berth will keep the Shoalsailer afloat in a worst case scenario.

 

How stable is the Shoalsailer?

 

The Shoalsailer has a stability curve similar to other monohulls and much better than the abrupt stability curves found in multihulls. There are two ways to calculate stability. Using the traditional "hull only" formula, the Shoalsailer shows 29,000 foot pounds of stability at 58 degrees of heel and remains positive until 112 degrees, meaning that the Shoalsailer will not capsize in any but extreme situations such as those encountered offshore in the Perfect Storm, or in the Roaring Forties in the Southern Ocean.

 

Shannon 35 Stability Curve

 

The Shoalsailer has a stability curve similar to other monohulls and much better than the abrupt stability curves found in multihulls. There are two ways to calculate stability. Using the traditional "hull only" formula, the Shoalsailer shows 29,000 foot pounds of stability at 58 degrees of heel and remains positive until 112 degrees, meaning that the Shoalsailer will not capsize in any but extreme situations such as those encountered offshore in the Perfect Storm, or in the Roaring Forties in the Southern Ocean.

 

Why does the cockpit have dual wheels and engine controls?

 

The dual wheels on the Shoalsailer provide a perfect position for docking and steering while watching sail trim and boat traffic. With the dual helms, the primary sheet winches are be placed directly in front of the helm stations so one person can easily tack the Shoalsailer by moving from wheel to wheel. Guests along for a day sail do not get in the way of the people sailing the boat with this dual wheel set-up. In addition, the dual wheels provide redundant systems for safety, as each steerer is linked to a rudder, and the rudders are connected by a drag link. If one steerer fails, the other will provide complete control.

 

How many people can the Shoalsailer comfortably accommodate?

 

The spaciousness of the cabin allows for two doubles and two single berths so six adults can sleep comfortably. The cockpit can accommodate up to ten people for daysailing. There is room for a month's worth of food and provisions for a liveaboard cruising couple. At Shannon, all interiors are custom designed to suit each owner’s specific cruising needs.