Design: Pekka Koskenkyla, Founder of the Nautor Swan and the 40m LOA Mirabellas

OceanBel 40


The OceanBel 40 is designed to meet the growing future requirements of green power. The batteries are charged by generators, sun or wind power created by the two propellers as explained below. A total of 140 sq meters of sun paneling is possible.

A Sailing Boat with the comfort of a Motor Boat

The OceanBel 40 is a high performance sailing boat with comfort and space of a power boat.


Hybrid-electric power with twin motors of 200kw (about 250hp) each

New sail plan for better performance and easier handling

Can be sailed by one person only

Six large double guest cabins

Large garage for several dinghies and a catamaran “minibus” for 12+1 persons

Designed for world cruising and independent of marinas and ports

Raised saloon with panoramic view

Big cold storage and laundry rooms

Designed for four season use and ideal for charter
Pekka Koskenkyla +33 6 69 39 70 30

oceanbel 128  oceanbel 40
From Oceanbel 128 to OceanBel 40 Boat Sailing Yacht

OceanBel 40 plan view

OceanBel 40 section view

OceanBel 40 interior view

Originally named OceanBel 128, now OceanBel 40.




–  New innovative keel with two functions:

a) Greatly reduced rolling in the down position 7 meters deep
b) Low draft in the up position of only 2 meters deep

–   Two hybrid electric motors with two functions

a)  Propulsion when under power
b) Generating electricity under sail

–    No extra weight with a big battery bank replacing the lead keel

–    New sail plan for more speed under sail

–    One person can sail the boat alone – no deck crew needed

–     Long range cruising and independent of marinas

–    Comfortable living and ocean crossings

–    Six double cabins for owner and guests and three for a crew of 5 to 6

–    Panoramic view from the saloon and the two dining areas


L.O.A :                40 m    —     131 ft
Draft min             2 m    —     6.5  ft
Draft max            7 m    —     23 ft
Beam                  10 m    —    33.2 ft
Displacement                200 tons

Propulsion: Two hybrid electric motors of 200 kW (about 250 HP each)

Construction in aluminium under Lloyds or Bureau Veritas supervision


The keel is a deep thin plate made of spring steel. It bends but retains its straight form. It can be adjusted to any angle from 2 to 7 meters deep from the waterline. We call it the keelboard. When it is down, the powerful leverage effect of seven meters will prevent rolling caused by waves coming from the beam. When at anchor it can even be lowered to touch the bottom for maximum effect. It moves freely up and down when it rests on the bottom and therefore is not effected by the tide.

Another advantage of the low draft is to be able to take the boat out of the water on a simple slipway or in a smaller dry dock anywhere in the world for repairs or for annual bottom painting.



Two generators of 200 kW each (about 2×250 HP) charging a large battery bank powering twin propellers. No waste of energy compared to a generator running non stop 24 hours for the four star hotel services, because power is consummed only as needed and when needed. The size of the battery bank is normally decided depending on maximum distance, that the boat will be able to cruise on electric power. In this case the battery bank can be very big, because the heavy battery bank replace part of the lead ballast of the same weight needed for stability and is located in the same place in the bilge.

The batteries can also be charged by wind power when sailing, as the  propellers will turn because of the flow of water. The electrical motors connected to the propeller shafts are modified to generate electricity when sailing.



The OceanBel 40 has two head sails (genoas), but no main sail. Both head sails have roller reefing for adjusting the size of the sails to the force of the wind. The sheets have captive winches in the engine room adjusting the sails to the direction and force of the wind. All this is controlled by the helmsman with push buttons.

In addition to being easier to handle this more effective sail plan also gives more speed under sail than an equal size sloop rig for the simple reason, that a genoa is more effective than the mainsail. This is a fact known to anybody, who has tried to sail with the main sail alone as compared to sailing with only the genoa. We have two of the more effective genoas.

In addition to the ballast weight the wide beam also reduces the angle of heel when sailing.



In addition to the normal two season cruising of summer in the Mediterranean and the winter in the Caribbean the OceanBel 40 is designed to be able to extend the season in other cruising areas for the whole year.  One alternative sailing area is the Bahama Islands, which could be an extension of the winter season by using spring and autumn, because the weather and sea are warmer than in the Caribbean or Florida at that time of the year. The reason is the warm Gulf Stream coming from the Gulf of Mexico going through the Bahama archipelago. There are no marinas in the Bahamas and the maximum draft is only two meters, that´s why it is perfect for the OceanBel 40. For these two reasons there are few yachts in the Bahamas compared to the Caribbean. Bahamas is a big archipelago with many small islands most of them uninhabited.

Another alternative for winter cruising, could be the Maldives islands and some other parts of the Southeast Asia. The longer season in these areas could even include spring and autumn with only the summer in the Mediterranean. There are many remote destinations such as smaller islands with no tourists. It is possible to find beautiful bays with good anchorage and to be the only boat there. The OceanBel 40 is designed and built to cruise in these remote destinations, because she is self-sufficient of food with a cold storage room with many freezers big enough to last for weeks or even months. She also has enormous storage space in the bilge with standing headroom all the way to the bow.

A well-equipped laundry room with washers and dryers is also important for autonomy.

Obviously with all the equipment and facilities the OceanBel 40 is also ideal for all year charter. The charter rate for a boat of this size and quality is 100 000 euros per week in the high season and 20 weeks of charter per year would be realistic with some flexibility for the low season rate.



The owner and guests are able to enjoy a panoramic view from the saloon forward, port and starboard even when seated. A view that is normally reserved for the skipper. The wheelhouse is forward of the saloon, and the upper part of the wall separating these two areas is glass. When the boat is under way the owner and guests are able to follow where the boat is heading. When the wind conditions are suitable for sailing the skipper would be steering the boat from one of the two steering stations on the upper aft deck to see the sails better.

Each cabin is properly sound insulated with thick bulkheads.

A big garage of about 70 square meters for several different size of dinghies/boats and for water toys.

The boom shown on the aft deck attached to the mast is for the support and storage of a rolled up sun awning inside that boom. The alternative would be a fixed sun roof.

This makes it possible to have 140 sq meters of sun panels together with the saloon roof



To get the best crew and to keep it, good accommodation is important. Here again our solution is original. The captain and the cook occupy a double cabin each and can take on board the person they live with provided that this person qualify as a crew member.

This makes it easier for these key members of the crew to stay on board for extended periods of time, which is one of the main objectives of this yacht. The third crew cabin has an upper fold down berth if needed.

The crew has a comfortable crew mess and their own dining area in the galley.



In addition to the superior performance and comfort the OceanBel 40 is also designed for charter twelve months a year in different parts of the world without being dependent on marinas. This is possible because of her long range and the big cold storage and laundry rooms etc.

The normal high season rate for a boat of this size is about 100.000 euros per week. With a flexible rate for the low season an occupancy rate of 20 weeks or more per year is possible.

There are many charter agents for big yachts. One of these could be appointed to be central agent for marketing and to manage the boat and crew for the owner.

Pekka Koskenkylä

It all started with the Swans

As a young man I founded and managed Nautor, the company building SWAN sailing yachts.

My next big yacht building project was the Mirabella sailing yachts built in Thailand by Concord Yachts, which I started and managed. At 40 meters L.O.A. these were the biggest sloops in the world at the time.

As there were no yacht building skills in Thailand we had some experts from Europe to instruct the locals. The interior for the boat was built in Finland and shipped to the yard for installation.

It all worked out so well that the first unit of the Mirabella yachts received a price of high quality at the Monaco Boat Show in 1992.

The third big project was to design and build my own full displacement power boat for world cruising. The yacht had some sailboat features such as internal lead  ballast in the bilge for more stability at sea. My wife and I spent seven years cruising with no crew, in different parts of the world including many ocean crossings.

With all this experience, I have now designed a new and more advanced cruising yacht, the OceanBel 40.

My ambition is to build and to create a new brand.

Pekka Koskenkylä´s design Mirabella.

Butch Dalrymple Smith

Butch worked for 18 years as the head of the design department of Ron Holland Yacht Design and as the head of Camper & Nicholson design office.

He has more practical all around experience about sailing yachts than most other naval architects, because he is also a experienced sailor.

Among others Butch was a crew member of the Swan 65 that won the first Whitbread Round the World Race, now known as Volvo Ocean Race.  He is the technical adviser for the design of the OceanBel 40 project. ​