The Macwester 27 Sailboat

The Macwester 27, designed by Jim Roy and produced in the UK by his company Macwester Marine, was a popular bilge-keeled sailboat of the 1970's.

A Macwester 27 Sailboat, demonstrating how bilge keels can make perfect sense!

Bilge keels enables an owner to take advantage of drying moorings which are always cheaper than deep-water moorings, but of course are less convenient.

However, if you run aground at the top of a spring tide in one of these, you're likely to remain there for rather a long time!

Nevertheless they are popular with sailors, particularly in the UK.

Published Specification for the Macwester 27

Underwater Profile: Twin keel (bilge keels) with skeg-hung rudder

Hull Material: GRP (fibreglass)

Length Overall: 26' 11" / 8.22m

Waterline Length: 23' 0" / 7.0m

Beam: 9' 2" / 2.80m

Draft: 4' 11" / 1.50m

Rig Type: Masthead Sloop

Displacement: 7,385lb / 3,350kg

Designer: CSJ (Jim) Roy

Builder: Macwester Marine Co. Ltd. (UK)

Year First Built: 1972

Owners Association: Macwester Owners Association

Published Design Ratios for the Macwester 27

Sail Area/Displacement Ratio: 13.9

Less than 16 would be considered under-powered;
16 to 20 would indicate reasonably good performance;
Over 20 suggests relatively high performance.

Ballast/Displacement Ratio: 33.4

Under 40: less stiff, less powerful
Over 40: stiffer, more powerful

Displacement/Length Ratio: 271

Under 100: Ultralight
100 to 200: Light
200 to 275: Moderate
275 to 350: Heavy
Over 350: Ultraheavy

Comfort Ratio: 24.7

Under 20 indicates a lightweight racing boat
20 to 30 indicates a coastal cruiser
30 to 40 indicates a moderate offshore cruising boat
40 to 50 indicates a heavy offshore boat
Over 50 indicates an extremely heavy offshore boat

Capsize Screening Formula: 1.9

Under 2.0 (the lower the better): Better suited for ocean passages
Over 2.0: Less suited for ocean passages

The Macwester 27: A Solid and Spacious Sailboat for Cruisers

The Macwester 27 is a bilge-keeled sailboat that was designed by Jim Roy and built by Macwester Marine in the UK from 1972 to 1980. The Macwester 27 is a popular choice among cruising sailors who want a boat that can handle coastal cruising and occasional offshore trips.

The boat has an aft cockpit with tiller steering and all sail controls are led back to the cockpit for easy handling. The cockpit is self-draining and has a locker for storage.

The Macwester 27 has a length of 8.2 meters (26.97 feet) and a beam of 2.79 meters (9.15 feet). The mast is deck stepped and simple to lower when necessary. The sail area is 30.57 square meters (329 square feet), which gives the boat a moderate sail-to-displacement ratio of 13.92.

The boat has a displacement of 3,350 kilograms (7,385 pounds) and a ballast of 1,120 kilograms (2,469 pounds), which gives it a high ballast-to-displacement ratio of 33.43¹. This means that the boat is relatively stable and stiff with a good righting capability. The boat has a draft of 1.5 meters (4.92 feet), which allows it to access shallow waters and anchorages.

The boat has a spacious interior with four berths in two cabins and standing headroom of 1.83 meters (6 feet). The forward cabin has a V-berth that can be converted into a double berth with an infill cushion. The main cabin has two settee berths that can also be used as single berths. The galley is located on the port side of the main cabin and has a gas cooker with grill, a sink and a cooler. The navigation station is located on the starboard side of the main cabin and has a chart table, instruments and an electrical panel. The head is located aft of the navigation station and has a marine toilet with a sink.

The Macwester 27 is a sailboat that has several advantages for cruising sailors, some of which are:

It has a lot of space and comfort for its size, both above and below decks;

It has a solid and robust construction that can withstand rough weather and seas;

It has a bilge keel design that allows it to dry out on tidal moorings or beaches;

However, the Macwester 27 also has some drawbacks, some of which are:

It is not very fast or agile, especially in light winds or upwind sailing. It may need help from the engine in such conditions.

It has a lively and less comfortable motion at sea under sail, which may cause seasickness or fatigue for some crew members.

It is not intended for ocean sailing or long-distance voyages.

Jim Roy, Yacht Designer

Jim Roy founded Macwester Marine, a company that built more than 1,500 yachts between 1964 and 1979. He designed the Macwester 26 and the Macwester 27, among other models.

The Macwester 26 was the first sailboat built by Macwester Marine. It was a clinker-built fractional sloop with a simple rig and a small, low-profile cabin.

The Macwester 27 was an improved version of the Macwester 26, designed with the help of dynamic tank-testing at Southampton University. It had a profiled and shaped ballast in cast iron bolted to the GRP stub keels.

Sailboats designed by Jim Roy and built by Macwester Marine include:

Macwester 26: A sturdy bilge-keeled cruiser with good interior space and simple rig, but compromised sailing performance and weather helm issues.

Macwester 27: An upgraded version of the Macwester 26 with better sailing performance and manoeuvrability, deeper draft, and profiled ballast.

Macwester Rowan: A smaller version of the Macwester 26 with a length of 6.7 m, a beam of 2.4 m, and a draft of 0.76 m. It had four berths, a galley, and a heads compartment.

Macwester Malin: A ketch-rigged version of the Macwester 27 with an aft cabin and cockpit, giving more accommodation and privacy.

Macwester Wight: A larger version of the Macwester 27 with a length of 9.75 m, a beam of 3 m, and a draft of 1.22 m. It had six berths, two heads compartments, and a spacious saloon.

The above text was drafted by sailboat-cruising.com using GPT-4 (OpenAI’s large-scale language-generation model) as a research assistant to develop source material; we believe it to be accurate to the best of our knowledge.