HR KO 0001

HYBRID ECO CRUISER

2 x lighter4 x smaller draft10 x more electric energyunsinkablecan rest on the bottomdoes not need fenders

HREKO ^

A number of factors were taken into account during the making of this concept. Factors such as the characteristic long islands that shield the Croatian Adriatic and prevailing winds of parallel directions to the coastline (NW-SE), ecological factors, a small crew, an older recreational sailor who likes to fish and to whom a deep keel and long mast are a nuisance, etc. It is suitable for sailors and nature enthusiasts that have time to wait for favourable winds, make longer routs and enjoy staying in shallow bays. HREKO 1200 (a 20% enlarged HREKO 1000, modified for open waters) has a total length of 14.4m and 1200 l of fresh water reserve. It might be interesting to seafarers around the world because its buoyancy chambers make it virtually unsinkable.

WHY HREKO 1000?

Joso Perkovićperkovic.joso@gmail.com

10 or 12 m?

JOSO PERKOVIĆperkovic.joso@gmail.comwww.hreko.com

TECHNICAL SPECIFICATIONS

Length over all (LOA)Total vessel lengthLength of water line (LWL)Dynamic water lineBeam (the hull)Beam over all (BOA)DraftDisplacement (excl. water ballast)Water ballastFuelWaterAir draftMainsailSelf tacking stay sailHead sail (genoa)Close hauled (sail area)Beam reach (sail area)Running (sail area)Wind + Solar energy productionBatteriesDiesel generator/ electric motorsSeawater desalinizationWater ballast pumps

* fresh water

998 cm1220 cm960 cm1140 cm372 cm426 cm40 cm2,5 t2 x 350 l*200 l100 l (+750 l)*11,90 m

221 m213 m241 m234 m262 m

2102 m (2 x 41 + 20)1,5 kW1600 Ah / 12 V10 kW / 2 x 5 kW25 l/h2 x 100 l/min

CATAMARAN

HREKO

MONOHULL

ANGLE OF HEELR

IG

HTIN

G M

OM

EN

T

One of distinguishing features on the boat is an adjustable traverse bipod mast (typically made of carbon) that is positioned halfway to improve downwind sailing. There is a specially designed convertible headsail that consists of two collapsed genoas with an insert in-between. The latter is an elongated 12 m long sail in the shape of a laurel leaf, also called patch sail. Genoas and the insert are fixed like piano hinges on a double fore stay. There are in fact two 6 mm thick dyneema fore stays. When drawn together tight (mast stands upright) the patch sail is folded in between the two genoas. At side wind it all functions

2like a standard genoa that has a 30-40 m surface area, except that there are two sheets of sail. When running 135°-225° wind quadrant, the genoas are fully unrolled and held in a “butterfly” position by two poles. The mast is leaned forward by 10° while the fore stays move apart and the patch sail is spread open. This

2gives about 100 m of sail with bulged shape. It resembles a “low aspect spinnaker” except that it is fixed on four spots. The full batten performance mainsail is not used during running, but furled in the boom. By restoring the mast to its upright position the fore stays come together and genoas are furled until the patch sail disappears. When sailing close hauled the main sail is

2used together with a 13 m self-tacking jib (stay sail). It is fixed with karabiners on a cable that is used to fasten the mast when it leans. When passing under a bridge or making repairs the mast can be lowered within minutes and raised again, even at rough seas.

The ecological component of HREKO is one of its strongest features. There are 8 of 2solar panels of which 6 m are under direct sunlight when the boat is turned

sideways to the sun. They are placed in such a way so that they don't interfere while sailing. The effect of shadows which is almost impossible to eliminate on sailing boats is also minimal. Three wind turbines achieve energy autonomy of the boat, each offering 350 W of potential power supply. The rotor blades can be folded in a neutral position during upwind sailing or when noise is an issue. In favourable conditions HREKO has the capacity to generate approximately 12 kWh of electricity per day from wind and sun. This equals up to 40% of maximum theoretical energy production and 60% of battery capacity maximum. It is sufficient for a 4 hour voyage on electric drive with a 3kW power output. Apart from wind, the drive system consists of a 10 kW diesel generator and two 5kW electric motors. The thrust of a 10kW electromotor is comparable to that of a 30 hp diesel engine. The boat is suitable to automate; e.g. remote control of electric motors, electric systems for reefing, autopilot, etc. During downwind sailing the output of wind turbines can be used to power the electric motors for extra speed. If however the intention is to charge the batteries, both the wind turbines and the electric motors can generate electricity through propellers. While sailing upwind, wind turbines can power the one submerged electric motor to eliminate resistance or to assist when tacking.

A CONCEPT OF ADJUSTABLE RIGGING

SUSTAINABLE DESIGN

MORE THAN 1 KW OF ELECTRIC ENERGY FROM WIND AND SUN

10°

HREKO has wind, diesel fuel and electric powered drive while the concept is of a hybrid between a performance sailboat hull, a catamaran and a RIB (Rigid Inflatable Boat). Combining underwater catamaran-like tanks/floats with RIB-like floats/tanks above water, on a light performance hull made of composite materials allows HREKO to be twice as light but have superior initial stability compared to a centreboard keel cruiser of the same size. Energy production and low displacement allows up to 50% less fuel consumption! The stability curve and sea behaviour is between that of a single-hulled sailing boat with a classic keel and that of a catamaran. I believe this concept of stability will be used more often in the future simply because it makes principles such as lightness, speed, stability, shallowness, comfort and safety, possible. A RIB type of dinghy

The concept is based on static and dynamic ballast, and the fact that (sea) water is 850 times heavier than air. Beside the shape and width of the hull, as well as 1000 kg of useful cargo positioned mostly below the water line, primary stability is maintained by two 350 l side tanks/keels. They also minimize the boat making leeway. When the boat heels by 14°-15°, the windward keel fully emerges from the water while the leeward “RIB- float” begins to submerge. If required water can be pumped at 2 × 100 l/min from the leeward submerged keel to the windward tank which makes a rigid core of “RIB-float”. All four oblong tanks have transverse bulkheads and are constructional elements of the hull. By using pumps and water ballast the total stability is almost doubled. It is the same as having a windward canted keel with a 160 cm long fin and a 1300 kg bulb. When heeling at 35° the stability is highest; comparable to having a 150 cm long windward canted keel with a 2200 kg bulb. One should bear in mind that water displacement is less than 3000 kg and draft is only 40 cm. During incident gibe when water gets caught inside the 'wrong' tanks, the soft part off leeward RIB -float still provides 700 l of buoyancy on a 1m limb. Considering that heeling over 115° leads to negative stability, a 25-50 l airbag triggers on top of the mast to prevent the boat from capsizing. In this way it remains at approximately 100° horizontal position with possibility of self-righting. Shifting water partially or fully from lower tanks to upper ones can be used to change the amplitude of rolling and possibly minimize interference with side waves.

INNOVATIVE CONCEPT OF BOAT DESIGN

HYBRID2

`ABAC 5

that slides in the stern like a bayonet is a structural part of the hull during sailing. It extends the water line considerably, allowing a 10 m boat to have some characteristics of a 40-footer. When moored in a marina it can serve as stern gangway. Longitudinal “RIB” floats are in fact water ballast tanks lined with 10 cm thick polyethylene sponge. As it covers a significant portion of the hull, it renders the fenders useless and provides additional sound and thermal isolation. HREKO is not suitable for regattas because of too little sail coverage when sailing upwind. It might be slow to manoeuvre, although the fact that it keeps direction easily is beneficial for autopilot. Two long but low keels allow for easier transport and maintenance on land. This also makes it suitable for shores of Western Europe where there are large tide fluctuations.

A NEW CONCEPT OF SAILBOAT’S STABILITY

AIRBAG

1000 k

g

15-20°

350

350

200

1300 kg

1000 kg

»

35°

350

350

1050>2100 kg

1000 kg

»

INCIDENTGIBE

700450 kg

1000 kg

»

»15-20°

350

200

500 kg

1000 kg1000 kg

160 cm