B&G Yacht Design

Boat Plans - Multichine 41 SK

Aluminium or steel long range swing keel cruising yacht.

The Multichine 41SK is the most versatile of the cruising sailboats in its category among our list of stock plans. Being neither too large, nor too small for a family to live aboard, the MC 41SK may be classified in the category of unrestricted offshore yachts. However, what makes the MC 41SK outstanding is its capacity of entering in shallow waters, a possibility denied to fixed keel monohulls of about the same size.

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The MC 41SK uses the same lines-plan of another of our designs, the MC 41, with the main difference that while the MC41 has a fixed fin-keel, the MC 41SK is specified to have a retractable swing-keel. We believe that this is one of the most promising ideas in yacht design. At any rate it’s like a dream come true being able to touch the yacht’s bow on a beautiful beach, just like those enviable catamarans, while having positive stability typical of monohulls.

Another very important aspect of being able to reduce draft is that it allows entrance to hurricane holes and storm shelters that may be inaccessible to comparable monohulls or that will be conditioned to a rising tide situation, which may not occur at the desired moment.

The MC 41SK can receive a crew of up to six persons with plenty of comfort. Possessing two private cabins, two heads, one of them en suite, the boat offers sleeping accommodations for two couples plus two more persons, one in the pilot berth placed opposite to the fore head, and the other in the dinette’s sofa, which is an extra berth when needed.

With a very strong hull and structure as is the case with the range of our metallic boat series, the Multichine 41 SK is a strong and seaworthy yacht, but at the same time a fast performer in all points of sailing.

Considering the large water and diesel tanks, the ample space available for gear and supplies, and all the other distinctive features of this design we are sure that its living aboard facilities are among the best in this size range.

The fact that the Multichine 41 is capable of beating in strong winds and heavy seas efficiently, with plenty of stability, and when running free, is extremely well balanced, with good course stability and easy steering, makes this boat a great choice for those who want to be prepared for good or bad weather, taking the sailing couple or family or the lone adventurer in all safety to distant shores.

Technical Data

Length Overall

12.48 m (40.9 ft)

Length Waterline

10.48 m (34.4 ft)


4.00m (13.1 ft)


1.20 m/2.70 m (3.9 ft/8.9 ft)

Fixed Internal Ballast

2,645 kg (5,826 lbs)

Movable Ballast

1,570 kg (3,458 lbs)


12,350 kg (27,203 lbs)

Fresh water capacity

640 l (170 gal)

Diesel capacity

360 l (95 gal)

Standing Headroom – Saloon

2.00 m (6’ 6”)

Standing Headroom – Front Cabin

1.86 m (6’ 1”)

Standing Headroom – Aft Cabin

1.85 m (6’ 1”)

Rig type


Mainsail Area

40.7 m2 (438 sq. ft)

Jib Area

37.3 m2 (401 sq. ft)

Stay Sail Area

20.0 m2 (215 sq. ft)

Gennaker Area

66 m2 (710 sq. ft)

Auxiliary Propulsion

50hp ~ 55hp


Steel or Aluminium

List of Plans

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MC41SK – S1 – Lines Plan

MC41SK – S2 – Mast and Sails

MC41SK – S3 – Interior Layout

MC41SK – S4 – Deck Layout

MC41SK – S5 – Structural Arrangement

MC41SK – S6A – Transversal Sections and Bulkheads

MC41SK – S6B – Transversal Sections and Bulkheads

MC41SK – S6C – Interior Sections 0 to 5

MC41SK – S6D – Interior Sections 5.5 to 7.5

MC41SK – S6E – Interior Sections 8.0 to 10.0

MC41SK – S7A – Swing Keel System and Keel plan

MC41SK – S7B – Special Fittings for Swing Keel System

MC41SK – S8A – Longitudinal Section Fwd

MC41SK – S8B – Longitudinal Section Aft

MC41SK – S9 – Custom Fittings

MC41SK – 10 – Watertight Door

MC41SK – 11 – Radar Tower

Boat Description

Interior layout:

A pivoting retractable keel requires building a case in the central area of the cabin, conditioning the interior layout to this contingency. The MC 41SK is wide enough to allow the installation of a dinette on one side of the keel trunk, leaving room for a corridor to starboard, the passageway to the fore cabin.

The galley is placed to starboard of this corridor and is quite large, with plenty of space for a freezer, four burners stove with oven and double sinks installed in a long counter next to the topside. The dinette on the opposite side is L shaped and the table is conveniently hinged to the swing-keel trunk. Aft of the galley there is an office/chart table of good proportions, and further back the owner´s cabin, with a private head with separate shower stall.

The forward area has a private double berth and another head with separated shower stall to port, while an extra crew bunk is located to starboard. This some of our customers have transformed in extra storage space.

A detail in the layout worth mentioning is the large aft compartment abaft the aft-cabin heads, with access from the heads back-wall and from the cockpit. That place is ideal for storing bulky items, like sail bags, inflatable dinghies, and so on. If a power generator is installed, it should be fitted inside this compartment.

Deck layout, standing rigging and sail plan:

A flush foredeck, small cabin trunk and large cockpit make for a simple and functional deck arrangement. A large cockpit locker and a good-sized stern platform are provided for convenience and easy access to the water. The cockpit seat behind the wheel can be made removable or pivoting to facilitate access to the cockpit from the very spacious transom scoop, where dealing with diving gear or fish cleaning are easy tasks.

The Multichine 41SK is cutter rigged with spreaders swept aft, a feature that allows dispensing running backstays, a nuisance in cruising sailboats. This rig is simple and efficient, in our opinion the best choice for an offshore sailing. The two foresails fitted with roller-furling gears allow for infinity of adjustments, keeping the boat balanced in practically any condition, enhanced by the possibility of altering trim by changing the keel longitudinal position. The mainsail has its foot with moderate dimensions, representing less load on the steering system, especially on the autopilot, besides improving sail handling, mainly when jibing in heavy weather. With average sized sail area, the MC41SK is capable of performing good daily runs with minimum stress for the crew.

Keel, rudder and auxiliary propulsion:

The swing keel solution employed in the MC 41SK is no doubt one of the hot features of the project. The working mechanism we adopted in the design is being successfully employed in many other boats of our design, functioning flawlessly even in the worst conditions. We specified a system to lift the keel in which two spectra ropes are pulled by a hydraulic piston. The great advantage of this system is to avoid damage in case of accidental collision, once the keel is free to swing up, and when it falls back, the impact is dissipated by a shock absorber.

The MC41SK has two options of rudders: twin rudders protected by skegs, which keep the draft low and allow for efficient control due to the increased rudder area and a fixed rudder placed behind a skeg, which protects the propeller blades when the boat is laying on a beach slope.

We opted for a non-retractable shallow (double or single) rudder of correct size, keeping the keel as the only retractable appendage, making the boat less dependent on complex systems.

With the same sail area as the one specified for the fin-keel version, the Multichine 41SK has a slightly heavier displacement than the other design, but on the other hand she is more stable than the MC41 when its swing keel is dropped.

Auxiliar propulsion recommended is a 50 to 55 HP diesel engine.

Boat Plans

Study Plans


Construction Plans


CNC Files


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