Irwin 43 Cc Mki
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About the Irwin 43 Cc Mki
Designed by Ted Irwin and first launched in 1984, this center cockpit cruiser represents solid American production boat building from the mid-1980s. The 43-footer showcases the practical design philosophy that made Irwin Yachts popular among serious cruising sailors seeking comfortable, seaworthy vessels for extended voyaging. The boat's generous beam of 13.58 feet creates exceptional interior volume, while the center cockpit configuration provides excellent separation between the forward owner's suite and aft guest quarters. Her fin keel with rudder on skeg offers a good balance of performance and directional stability, making her well-suited for both coastal cruising and offshore passages. The cutter rig provides versatility in sail handling, particularly valuable for shorthanded crews or challenging conditions. With a displacement of 26,000 pounds and 8,000 pounds of ballast, she carries herself with authority through seas while maintaining reasonable performance under sail. The comfort ratio of 32.35 indicates a motion that favors seakindliness over speed, ideal for long-distance cruising. Her capsize screening value of 1.84 suggests good stability characteristics for offshore work. The substantial 62-horsepower engine provides reliable auxiliary power for tight quarters or windless conditions, reflecting the boat's serious cruising intentions.
Core Dimensions
LOA (Length Overall)
45.50 ft / 13.87 m
LWL (Waterline Length)
35.50 ft / 10.82 m
Beam
13.58 ft / 4.14 m
Max Draft
4.92 ft / 1.50 m
Displacement
26,000.00 lb / 11,793 kg
Ballast
8,000.00 lb / 3,629 kg
Ballast Type
Lead
Sail Area (Reported)
956.00 ft² / 88.82 m²
Design & Construction
Hull Type
Fin with rudder on skeg
Rigging Type
Cutter
Construction
FG
Designer
Ted Irwin
Builder
Irwin Yachts (USA)
First Built
1984
Associations
Irwin Facebook Group
Related Sailboats
["Irwin 43 Cc Mkii" · "Irwin 46" · "Endeavour 43" · "Morgan 45 4" · "Cape Dory 45"]
Owner Reviews
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Known Issues & What to Watch For
Irwin boats of this era are known for thin deck laminates with minimal core support around deck hardware, leading to widespread stress cracking and flexing around winch bases, cleats, and stanchion bases. Fastener pull-through and water intrusion into balsa core around these fittings is extremely common.
The balsa core used in the deck frequently shows widespread wet rot, particularly amidships and forward of the mast where foot traffic is heaviest. Tap testing typically reveals extensive soft areas that require invasive repair.
The deck-to-hull joint on Irwin boats of this period is an outward-turning flange covered by a vinyl or aluminum rub rail. This joint is prone to separation and water intrusion; the rub rail often conceals significant deterioration of the bonding.
The encapsulated or bolted fin keel on Irwin 43 CC models is known to develop weeping at the keel-to-hull joint. Stress cracking at the leading edge of the keel stub is common, and the joint should be carefully probed for voids or movement.
The center-cockpit configuration places significant compression loads on the interior structure supporting the mast. The mast step and compression post area should be inspected carefully for delamination or crushing of the hull structure beneath, as Irwin's interior laminate in this area was often inadequately reinforced.
Chainplate knees and backing structures on Irwin boats of this vintage are frequently glassed to balsa-cored hull sides rather than solid glass or structural bulkheads, leading to chainplate pull-away under load. Verify that chainplates are backed to solid laminate or structural members.
Bulkhead-to-hull tabbing is often inadequate and shows delamination on many surviving examples. Major bulkheads should be tapped and inspected for separation, as Irwin's production practices of this era resulted in relatively thin tabbing that deteriorates with age and flexing.
Original wiring in Irwin boats of this era is typically undersized, improperly fused, and frequently modified by multiple owners over 30+ years. A complete rewire is often necessary; pay particular attention to the DC panel and battery connections for signs of heat damage or corrosion.
The large center-cockpit bridgedeck area is prone to flexing and cracking of the gelcoat, and the cockpit sole often shows soft spots from water intrusion into the structural foam beneath. Check carefully for delamination under the cockpit sole.
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Performance Ratios
SA/Displacement
Sail Area to Displacement ratio measures how much sail power a boat has relative to its weight. Higher values mean more performance and speed.
Under 14 — Heavy cruiser, slow14–18 — Cruising sailboat18–22 — Cruiser/racerOver 22 — Performance racer
17.5
Ballast/Displacement
Ballast to Displacement ratio shows what percentage of the boat's total weight is ballast. Higher values generally mean better initial stability and stiffer sail carrying.
30–35% — Typical cruiser35–45% — Stiff performance boatOver 45% — Racing oriented
30.77
Displacement/Length
Displacement to Length ratio measures how heavy a boat is relative to its waterline length. Lower values mean a lighter, faster boat.
Under 100 — Ultralight racer100–200 — Light cruiser/racer200–300 — Moderate cruiser300–400 — Heavy cruiserOver 400 — Very heavy
259.44
Comfort Ratio
Ted Brewer's Comfort Ratio predicts how comfortable a boat will feel in offshore conditions. Higher values mean a steadier, more comfortable motion in a seaway.
Under 20 — Uncomfortably rough20–30 — Acceptable coastal30–40 — Good offshore comfortOver 40 — Very comfortable offshore
32.35
Capsize Screening Formula
The USHS Capsize Screening Formula estimates offshore capsize risk. Lower is safer — values under 2.0 are considered acceptable for offshore sailing.
Under 2.0 — Safe for offshore2.0–2.2 — Borderline offshoreOver 2.2 — Coastal use recommended
1.84
Hull Speed
Hull Speed is the theoretical maximum speed of a displacement hull, calculated from waterline length. Most cruising sailboats reach this speed in moderate conditions.
7.98 kn
S# (Speed Number)
The Speed Number (S#) is a quick performance index. Higher values indicate a faster, more powerful design relative to its size.
Under 3.0 — Slow cruiser3.0–5.0 — Average cruiser5.0–7.0 — Performance cruiserOver 7.0 — Racer
2.13
Pounds/Inch Immersion
Pounds per Inch Immersion (PPI) tells you how much weight is needed to sink the boat one inch. Useful for calculating how additional gear and stores affect waterline.
1,722.56 pounds/inch
SA/Displacement (Calc)
Calculated Sail Area to Displacement ratio using actual measured sail dimensions rather than reported values. More precise than the reported SA/Disp figure.
17.5
Rig Dimensions
I (Foretriangle Height)
53.75 ft / 16.38 m
J (Foretriangle Base)
19.25 ft / 5.87 m
P (Mainsail Luff)
46.17 ft / 14.07 m
E (Mainsail Foot)
19.00 ft / 5.79 m
SA Fore
517.34 ft² / 48.06 m²
SA Main
438.62 ft² / 40.75 m²
SA Total (100%)
955.96 ft² / 88.81 m²
Est. Forestay Length
57.09 ft / 17.40 m
Mast Height (DWL)
58.00 ft / 17.68 m
Engine & Accommodations
Engine Type
Diesel
Horsepower
62
Fuel Capacity
107 gals / 405 L
Water Capacity
185 gals / 700 L
How It Compares
vs. Endeavour 43, Irwin 46, Morgan 45 4
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Dimensions
LOA
Irwin 43 Cc Mki ★
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Morgan 45 4
LWL
Irwin 43 Cc Mki ★
Endeavour 43
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Beam
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Displacement
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Ballast
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Sail Area
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Performance
PHRF Rating
(lower = faster)
Irwin 43 Cc Mki ★
Endeavour 43
Irwin 46
Morgan 45 4
SA / Displacement
(higher = more powerful)
Irwin 43 Cc Mki ★
Endeavour 43
Irwin 46
Morgan 45 4
Ballast / Disp
(higher = stiffer)
Irwin 43 Cc Mki ★
Endeavour 43
Irwin 46
Morgan 45 4
Comfort Ratio
(higher = more comfortable offshore)
Irwin 43 Cc Mki ★
Endeavour 43
Irwin 46
Morgan 45 4
Capsize Screening
(lower = safer)
Irwin 43 Cc Mki ★
Endeavour 43
Irwin 46
Morgan 45 4
Displacement / Length
(lower = lighter)
Irwin 43 Cc Mki ★
Endeavour 43
Irwin 46
Morgan 45 4
Hull Speed
Irwin 43 Cc Mki ★
Endeavour 43
Irwin 46
Morgan 45 4
Speed Number
(higher = faster)
Irwin 43 Cc Mki ★
Endeavour 43
Irwin 46
Morgan 45 4