Introducing the SeaHorse H5: the low-flying yacht revolutionising maritime travel

Words by Dawn Zol­di

In the ever-evolv­ing world of mobil­i­ty, Sea­Horse Air Lim­it­ed aims to rede­fine mar­itime trav­el with its rev­o­lu­tion­ary low-fly­ing yacht, the Sea­Horse S5.

The first prod­uct of a joint ven­ture between Flow­copter (Edin­burgh, UK) and Evdron (Sin­ga­pore), the H5 aims to dis­rupt the tra­di­tion­al yacht and avi­a­tion sec­tors by intro­duc­ing a unique ‘fly­ing yacht ser­vice’ that com­bines the ele­gance and func­tion­al­i­ty of a lux­u­ry sea­far­ing ves­sel with the speed and agili­ty of a low-fly­ing air­craft — all while remain­ing dis­tinct from either tra­di­tion­al yachts or ver­ti­cal take-off and land­ing (VTOL) air­craft.

Designed to nav­i­gate the open seas and soar just above the waves, the S5 will cut down a typ­i­cal 12–15 hours fer­ry jour­ney of 300 km to just 2 hours, but priced at no more than the upper end of cur­rent fer­ry pric­ing. S5 has the poten­tial to rev­o­lu­tion­ize mar­itime trav­el across a wide spec­trum of cus­tomers, from reg­u­lar fer­ry pas­sen­gers, coastal road com­muters and adven­tur­ers to gov­ern­ment pub­lic safe­ty and enter­prise logis­tics pro­fes­sion­als.

Designed for Mar­itime Trav­el

Unlike VTOLs made for urban air mobil­i­ty (UAM), such as those made by Joby or Archer, Sea­Horse Air Lim­it­ed pur­pose-built its flag­ship S5 for mar­itime envi­ron­ments. It is a yacht that can fly, and could help define a new Mar­itime Air Mobil­i­ty (MAM) cat­e­go­ry of advanced air mobil­i­ty (AAM).

With a max­i­mum take­off weight (MTOW) of 1400 kg, the Sea­Horse H5 oper­ates as a low-fly­ing yacht that can fer­ry up to 5 peo­ple and/or car­go along coastal regions and islands. This ground­break­ing inno­va­tion will oper­ate just 15 meters (50 feet) above sea lev­el (ASL), low­er than the masts of typ­i­cal sail­ing yachts.

It will nav­i­gate its way through waters as a yacht when near har­bors, mari­nas or jet­ties and seam­less­ly tran­si­tion between sail­ing and fly­ing modes. H5 will car­ry 3 hours of fuel for a range of up to 450 km, fly­ing up to 3 hours at a stretch at 150 kmph. It can land on demand in just 8 sec­onds on sea, beach or sol­id ground. 

Sea­Horse Air is engi­neered for the con­di­tions often encoun­tered at low alti­tudes above the sea such as high humid­i­ty, salty air, rain, high speed winds and oth­er adverse weath­er con­di­tions.

Its VTOL design and amphibi­ous capa­bil­i­ty elim­i­nates the need for tra­di­tion­al infra­struc­ture like ports, jet­ties, mari­nas, run­ways, and makes it an ide­al solu­tion for mul­ti­ple chal­lenges in remote areas. It can land on demand in just 8 sec­onds on sea, beach or sol­id ground. 

 Ground­break­ing New Tech­nol­o­gy

Sea­horse H5 will also be the world’s first mul­ti-rotor VTOL in the > 1,500 kg MTOW cat­e­go­ry to be pow­ered by Flowcopter’s patent­ed Dig­i­tal Dis­place­ment Hydraulic Hybrid Dri­ve. It includes a dig­i­tal dis­place­ment® hydraulic pump, hydraulic motors, hydraulic hos­ing and a Rotax 917i light air­craft engine as its pow­er plant. 

Here’s how it works. Hydraulic pres­sure is con­vert­ed to rota­tion­al motion, which is then trans­ferred to the pro­pellers via a rotor hub on each motor. The robust hydraulic trans­mis­sion pro­vides very high torque to 8 inde­pen­dent­ly con­trol­lable lift rotors, with pre­cise elec­tron­ic con­trol of rotor speeds on com­mands received from the flight con­troller.

By increas­ing or decreas­ing the flow rate of a giv­en out­let, the RPM of the con­nect­ed motor is sim­i­lar­ly increased or decreased. From there on, the avi­a­tion prin­ci­ples are the same as any eVTOL, but with great­ly reduced sys­tem weight and com­plex­i­ty.

The inno­v­a­tive use of hydraulic tech­nol­o­gy elim­i­nates the need to charge exhaust­ed bat­ter­ies. This gives the Sea­horse H5 three game chang­ing advan­tages in terms of indus­try ‘bests’

• High­est pay­load to MTOW ratio (650kg pay­load on an MTOW of 1600 kg — about 40%), 200 per cent high­er than the best of today’s eVTOLs.
• High­est range / endurance (450 km on a full tank with max­i­mum design pay­load of 600 kg), 200 per cent high­er than the best of today’s eVTOLs.
• Quick­est turn­around time between flights, as the Sea­horse H5 needs just five to 10 min­utes (to fill petrol), as opposed to a typ­i­cal 60 min­utes need­ed to charge bat­ter­ies by the best of today’s eVTOLs. (note: This also dras­ti­cal­ly reduces the need for infra­struc­ture at take­off and land­ing points).

Safe­ty First

As a result of the hydraulic system’s very high pow­er-to-weight ratio, the Sea­horse H5 is designed to sur­vive the fail­ure of half of its dri­ve­train. It can stay air­borne or descend safe­ly on water or any near­by beach, deck or sol­id ground in a mere 8 sec­onds, on just 4 of its 8 lift rotors in an emer­gency. 

The entire craft is designed to sur­vive a free fall on water from its intend­ed oper­at­ing height of 50 feet. Pas­sen­gers will always wear a life jack­et, and each seat has airbags.

Engines, propul­sion sys­tems and fuel tanks place­ment in the 2 floats also make the pas­sen­ger cab­in a safe place.

Pas­sen­ger Com­fort

Each pas­sen­ger gets an ergonom­ic win­dow seat with a panoram­ic view. All seats have lux­u­ri­ous legroom, head­room and aisle space for a 3‑hour jour­ney, cup hold­ers, pull out trays, mobile charg­ing and read­ing lights. 

The H5 comes equipped with air-con­di­tion­ing, a ful­ly func­tion­al toi­let, wash basin, ade­quate stowage of lug­gage and in-flight inter­net con­nec­tiv­i­ty. For cus­tomers with dis­abil­i­ties, its entry / exit ramp accom­mo­dates wheel­chairs and even stretch­ers.

To elim­i­nate engine noise com­plete­ly, the propul­sion sys­tems have been put on the floats instead of the main fuse­lage with the cab­in. The pro­pellers too are designed for low noise. This enables con­ver­sa­tions that would oth­er­wise be dif­fi­cult in craft such as heli­copters and many small planes.

Deep­ak Patha­nia, Chief Design & Inno­va­tion Offi­cer, said: “The H5 employs a unique patent-pend­ing ‘Rotor Clus­ter Tilt’ sys­tem to enhance pas­sen­ger com­fort. One of the strug­gles for oth­er wing­less mul­ti-copters has been that the cab­in tilts for­ward at high­er speeds and tilts back when speeds reduce.

“Some craft have solved the prob­lem with vec­tor thrust sys­tems in each pro­peller, but this great­ly adds to weight and com­plex­i­ty.”

He con­tin­ued: “With our unique Rotor Clus­ter Tilt­ing sys­tem, the pas­sen­ger cab­in remains hor­i­zon­tal, while the entire frame with all the rotors tilts as one unit using only one set of actu­a­tor and one sin­gle piv­ot point.”

Oper­a­tional Flex­i­bil­i­ty 

The S5’s abil­i­ty to take off or land ver­ti­cal­ly from beach­es or sol­id ground at the sea’s edge elim­i­nates the need for infra­struc­ture at either end, such as ports, run­ways, jet­ties or charg­ing sta­tions.

This makes the S5 ide­al for remote and unchart­ed des­ti­na­tions. The only infra­struc­ture required is the abil­i­ty to fill petrol / ethanol after about three hours of fly­ing time. The refu­el­ing process takes about five min­utes.

The Sea­horse is capa­ble of long hauls (400km) and short hops (say 5km) with equal ease. This adds to its oper­a­tional flex­i­bil­i­ty. 

Green Fuel 

The S5’s avi­a­tion grade sys­tem is cer­ti­fied to  use petrol as well as ethanol (wher­ev­er it’s avail­able). Ethanol is a green, net-zero bio­fu­el option which is also far low­er in cost than petrol, and becom­ing more wide­ly avail­able in many major mar­kets where Sea­Horse intends to oper­ate.

A Sea of Use Cas­es

Sea­Horse intends to part­ner with reg­u­lar fer­ry oper­a­tors to pro­vide their pre­mi­um cus­tomers a six to eight faster alter­na­tive at prices no high­er than the upper end of fer­ry prices. The H5 will short­en the time tak­en for a 300km sea jour­ney to 2 hours, in con­trast to the 12–15 hours tak­en on a reg­u­lar pas­sen­ger fer­ry. This dif­fer­ence changes the game for mar­itime trav­el­ers.

For those sim­ply seek­ing a unique and thrilling expe­ri­ence, Sea­Horse also plans to offer short recre­ation­al low-fly­ing, slow-paced joy rides at resorts, such as those in the Mal­dives or Fiji.

This Sea­Horse one-of-a-kind expe­ri­ence will allow guests to ven­ture out a cou­ple of kilo­me­ters into the sea, view an exhil­a­rat­ing aer­i­al per­spec­tive and then land the water for a few min­utes, unlike any oth­er “ride” out there.

For mar­itime search and res­cue (SAR), the S5 will be equipped with advanced life sup­port sys­tems and the abil­i­ty to accom­mo­date a com­plete stretch­er. Its agili­ty, speed, abil­i­ty to gen­tly land and take off from water, when com­bined with its three hours of endurance, make it an invalu­able asset in emer­gency SAR sit­u­a­tions on sea, at islands and along coasts.

The Sea­Horse S5’s ver­sa­til­i­ty extends to car­go deliv­ery ser­vices. It can facil­i­tate quick trans­porta­tion of sup­plies to and from resorts, ships, remote islands and hard-to-reach coastal loca­tions.

The S5 can also serve as an acces­so­ry to larg­er ships. Designed to take off from and land on open decks, it can act as an aux­il­iary craft.

With its diverse range of use cas­es, Sea­Horse stands poised to rev­o­lu­tion­ize not only lux­u­ry mar­itime trav­el but also var­i­ous indus­tries and sec­tors that oper­ate in and around coastal regions by offer­ing flex­i­bil­i­ty, speed and ver­sa­til­i­ty. The poten­tial use cas­es for the future S5 remain as vast as the seas over which it will fly, and the imag­i­na­tions of its poten­tial users.

To learn more about Sea­Horse Air Lim­it­ed con­tact anurag.gupta@seahorseair.com