Seafarer 23 Kestrel (Daysailor) is a 23′ 0″ / 7 m monohull sailboat designed by Sparkman & Stephens and built by Amsterdam Shipyard G. de Vries Lentsch and Seafarer Yachts starting in 1963.
- Designer
- Sparkman & Stephens
- Associations
- ?
- # Built
- ?
- Hull
- Monohull
- Keel
- Stub + Centerboard
- Rudder
- ?
- Construction
- FG
Dimensions
- Length Overall
- 23′ 0″ / 7 m
- Waterline Length
- 16′ 6″ / 5 m
- Beam
- 6′ 11″ / 2.1 m
- Draft
- 2′ 3″ / 0.7 m — ?
- Displacement
- 3,700 lb / 1,678 kg
- Ballast
- 1,400 lb / 635 kg (Iron)
Rig and Sails
- Type
- Sloop
- Reported Sail Area
- 229′² / 21.3 m²
- Total Sail Area
- 229′² / 21.3 m²
Mainsail
- Sail Area
- 127′² / 11.8 m²
- P
- 23′ 0″ / 7 m
- E
- 10′ 11″ / 3.4 m
- Air Draft
- ?
Foresail
- Sail Area
- 102′² / 9.5 m²
- I
- 26′ 10″ / 8.2 m
- J
- 7′ 7″ / 2.3 m
- Forestay Length
- 27′ 10″ / 8.5 m
Auxilary Power
- Make
- ?
- Model
- ?
- HP
- ?
- Fuel Type
- ?
- Fuel Capacity
- 9 gal / 34 l
Accomodations
- Water Capacity
- 15 gal / 57 l
- Holding Tank Capacity
- ?
- Headroom
- ?
- Cabins
- ?
Calculations
- Hull Speed
-
5.4 kn
Classic: 5.44 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.
Formula
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
- Sail Area/Displacement
-
15.3
<16: under powered
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.
Formula
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.
- Ballast/Displacement
-
37.8
<40: less stiff, less powerful
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.
Formula
Ballast / Displacement * 100
- Displacement/Length
-
367.5
300-400: heavy
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.
Formula
D/L = (D ÷ 2240) ÷ (0.01 x LWL)³
- D: Displacement of the boat in pounds.
- LWL: Waterline length in feet
- Comfort Ratio
-
23.1
20-30: coastal cruiser
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.
Formula
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
- Capsize Screening
-
1.8
<2.0: better suited for ocean passages
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.
Formula
CSV = Beam ÷ ³√(D / 64)
- Beam: Width of boat at the widest point in feet
- D: Displacement of the boat in pounds
Notes
S&S design #1631.
Also called KESTREL 22. ‘DAYSAILOR’ is a designation used here for at least 2 versions of this yacht. There were actually 2 deck layouts and 2 accommodation plans offered, resulting in four models: CATALINA, NASSAU, NANTUCKET and MONHEGAN. The ‘NANTUCKET’ version, shown above, has a smaller cabin and longer cockpit.
Stern overhang seems to have varied between versions, (possibly to accommodate the outboard motor well). The original S&S design lists LOA as 22’. KESTREL seems to be an earlier name that Seafarer gave to this design.
By 1970 a boat with this same profile was being promoted by Seafarer as the SAIL’N TRAIL 23 OLYMPIC.
The later SAILMASTER 22, by the same Dutch builder, but sold by another American company, is the same design though it was assigned a new design number. (#1743)
Further adding to the confusion is the later, American built SEAFARER 23, which is a completely different design. (Rig dimensions are from the original S&S sailplan but are not necessarily consistent from one boat to another.)
