Sail Course ® Section 3, Boat Design and Hull Types.

Sail Course®

Section 3, Boat Design and Hull Types

Sail Course®

Boat Design and Hull Types:

Identify various hull configurations such as:

a. Full keel.

b. Full keel with cut away fore foot.

c. Fin keel with balanced rudder.

d. Fin keel with skeg rudder.

e. Centerboard hull.

f. Daggerboard.

g. Leeboard.

Sail Course®

Figure 3–1 Entry Angle

Sail Course®

Figure 3–3 Full Keel with Cut-away Forefoot

Sail Course®

Figure 3–4 Fin Keel with Skeg Rudder

Sail Course®

Figure 3–5 Fin Keel with Spade Rudder

Sail Course®

Figure 3–6 Bulb Keel

Sail Course®

Underbody Shapes

Sail Course®

Figure 3-7 Winged Keel

Sail Course®

Figure 3–8 Winglets on Keel

Sail Course®

Figure 3–9 Canted Keel

Sail Course®

Figure 3–10 Water Ballast

Sail Course®

Figure 3–11 Small Centerboard

Sail Course®

Figure 3–12 Daggerboard Hull

Sail Course®

Figure 3–13 Centerboard Keel

Sail Course®

Note centerboard and pendant

Sail Course®

Figure 3-14leeboards

Sail Course®

Figure 3-15 Bilge Keels

Sail Course®

Figure 3–17 Catamaran

Sail Course®

Figure 3–18 Trimaran

Sail Course®

A cruising trimaran

Sail Course®

Figure 3–20 Transom Hung Rudder and Tiller

Sail Course®

Vocabulary

Ballast. Weight carried low in boat to improve trim or stability.

Board Boat. Small (car top) centerboard sailing dinghy with very low topsides and virtually no cockpit.

Centerboard. Pivoted board that can be lowered through a slot in the keel to reduce leeway.

Daggerboard. Sliding board that can be lowered through the keel to reduce leeway.

Displacement. The weight of water displaced by a floating vessel; hence, the weight of the vessel itself.

Gudgeon and Pintle. A metal eye and matching pin used to mount a rudder on the sternpost or the

transom of a boat.

Leeway. Sideways movement of a boat through the water, caused by wind or current. Also, the angular

difference between the true course steered and the true course over ground.

Stringer. A fore-and-aft structural member of a hull.

Tiller. A lever attached to the upper end of a rudder stock, used by the helmsman to turn the rudder.

Wetted surface. The portion of a vessel’s exterior which is in contact with the water.

Sail Course®

Section 3, Supplemental Illustrations

Sail Course®

Design Parameters- Intended use

- Size

- Aesthetics

- Cost

- Hull shape

-- Minimum water resistance

-- Maximum leeway resistance

Sail Course®

Functions of Keel

• Reduce Leeway

• Lower Center of Gravity– Increase Stability

Sail Course®

Boat Design Summary

• Fiberglass most common hull material• Keels evolved from Full to Bulb

– or Wing– Prevents leeway

• Waterline length determines max speed• Wetted surface determines water friction

Sail Course®

Full Keel

Sail Course®

Fin Keel, Spade Rudder

Sail Course®

Winged keels come in different shapes

Sail Course®

Bulb Keels

Sail Course®

Bulb Keel on model of America’s Cup boat

Sail Course®

Dutch Sailboat with LeeBoards

Sail Course®

What kind is this one?

Sail Course®

Lots of room on a catamaran

Sail Course®

Sailboat with HydroFoil Wings for lift

Sail Course®

Trimaran – what is hung from the center hull?

Sail Course®

A large trailerable trimaram.

Sail Course®

End of Section 3 Slides