Technical details

Business history

Origins in Semler & Mathiassen in 1888; marine installations from 1945 and an Esbjerg offshore unit from 1980.

Average group employment (2025)

2,123 employees across the group in 2025; not Danish-operator headcount.

SemSound IP: Amplifier frame limit

Up to 2,000 W; 2HE V2000SEM frame, up to ten modules; module maxima cannot be combined above frame limit

SemSound IP: Router I/O

48

SemSound IP: Frames

Up to 64

SemSound IP: Stored messages

Up to 64; Up to 40 minutes total

Adaptors and reducers: Metric thread range

M16–M75; SAX/SRX/SAVX catalogue; model-dependent

BC125 and BC150 beacons: Ingress protection

IP66/67

BC125 and BC150 beacons: Ambient at T6

−40 to +55 °C; Selected 125/150 Ex configurations; T5/T4 have different maxima

SD125 and SD150 sounders: Sound level

Up to 115 dB; At 1 m, tone/configuration-dependent

KAC call points and accessories: WCP3 ingress protection

IP67

KAC call points and accessories: WCP3 maximum supply

30 V DC

KAC call points and accessories: WCP3 switch rating

2 A

Offshore wind history

Offshore wind activity began in 2001; 1888 origins describe predecessor-business heritage, not the incorporation date of the current legal entity.

Emden heavy-lift facility

Gantry crane up to 450 t at the German group service base, with component overhaul/storage, quay access and 24/7 control room; not Danish workshop capacity.

Floating substation development

400 MW triangular three-column concept developed with ISC and Inocean; Aalborg basin testing was scheduled for Q4 2024. The development target does not establish a delivered commercial platform.

Structural analysis tools and methods

ANSYS and STAAD Pro with 3D CAD; static, dynamic, fatigue, buckling, modal, lifting and sea-motion analysis.

SemTETRA architecture (2016)

One- and two-carrier base-station configurations, SIP and packet-data interfaces; historical configuration scope, not a current cybersecurity guarantee.

TETRA air repeater installation

Tower and transition-piece radio outputs; optional SNMP monitoring and UPS in the described 2014/2015 design.

SemSound IP amplifier configuration

150 W or 500 W amplifier modules in 25 W steps; 19-inch 2HE V2000SEM frame holds up to ten modules subject to a combined 2,000 W frame limit.

SemSound IP call station configuration

1–50-button station configurations; configured system supports up to 64 stored messages and 40 minutes total message duration.

Private LTE/5G radio bands

Partner Ericsson equipment in the described 800 MHz–3.8 GHz range; coverage and data rate depend on spectrum, radio design and installation.

Inergen IG-541 composition

52% nitrogen, 40% argon and 8% carbon dioxide; Fire Eater technology integrated into project-specific suppression systems.

Compressed-air foam configuration

316 stainless-steel skid with up to three mixing chambers; ARC1 control and manual, electric or pneumatic release options. FM approval applies to the selected configuration.

Deck-integrated firefighting media

1% or 3% foam configurations; water-only application is for suitable passive fire-retardant aluminium helidecks. NFPA 418 and CAP 437 are design references for the installation.

DSPA aerosol design life

15-year service life for the described aerosol models; protected-space design and model approval determine suitability.

SemSafe commercial supply scope

Water-mist nozzles and spares supplied for offshore assets and jack-up rigs; other installation markets are excluded by the catalogue.

MINI and MAXI electrical test-panel supply

400/230 V at 50 Hz or 440/230 V at 60 Hz; distinct supply configurations for the installation.

Decom360 planning method

P&ID-based visual work packages support drain, flush, isolation, hazardous-material mapping and structural removal preparation; specialist handling is separate from a waste-disposal licence.

Marine drive partner scope

Danfoss Marine Service Partner from November 2025, servicing installed drives on ships and rigs worldwide.

SCR technology and integration roles

Under the 27 August 2026 cooperation, H+H owns the SCR technology; Semco is the preferred integration and aftersales partner.

Naval programme role

Platform integration through Danske Flådeskibe K/S with Terma, OMT and PensionDanmark; minority investment in Stormborn supports its X-WAVE unmanned-vessel technology, which is not Semco-owned technology.

Balance-of-plant performance examples

8–10% cost savings and 99% availability are examples in the performance-based service proposition, not unconditional results or guarantees for every asset.

Fengmiao 1 offshore substation: engagement scope

Electrical EPCI for Copenhagen Offshore Partners’ 495 MW Taiwan project with PTSC, scheduled October 2023 to February 2027. Local engineering and novated equipment packages form part of the delivery split.

TenneT balance-of-plant maintenance: engagement scope

Preventive and corrective work on Dutch and German HVAC/HVDC offshore infrastructure under the agreement running to 2027.

Global Tech I turbine service: engagement scope

German group business Wind Multiplikator, renamed Semco Maritime Offshore Wind Service GmbH in July 2026, undertook service of 80 AREVA M5000 turbines from January 2026 under a ten-year agreement with a five-year option.

Rødsand 2 medium-voltage work: engagement scope

Transformer, switchgear, cable, relay, breaker and connector work for RWE with KK Wind Solutions, described as ongoing from 2023.

Scylla vessel mobilisation: engagement scope

For Seajacks UK in Esbjerg, October 2020 to February 2021 work included 700 tonnes of sea fastening, reinforcement, ballast-water work, thruster seals and hull coating.

Wind Orca and Wind Osprey crane upgrades: engagement scope

Crane-upgrade support for Cadeler in Rotterdam, October 2023 to March 2024, included boom rests, pedestals, electrical work and mooring-equipment recertification.

Offshore wind decommissioning study: engagement scope

Completed a 2025 study for a confidential German customer comparing decommissioning, life-extension and repowering scenarios.

Offshore eCharger FEED: engagement scope

Prepared a 2025 FEED study for a confidential North Sea customer covering HV/MV/LV equipment, 3D layout, SCADA, risk and capital cost.

Open and closed offshore substation concepts: engagement scope

Compared platform layouts and capital/operating implications for a confidential European customer in 2024.

Mediterranean floating-substation pre-FEED: engagement scope

Developed 66/220 kV floating-substation scenarios and EPCI cost estimates for a confidential Mediterranean project in 2023.

Harbour Energy shore-power pre-FEED: engagement scope

Prepared a 2023 pre-FEED study for Harbour Energy Partners in the UK for approximately 200 MW HVDC shore power, covering topsides, jacket, cable and onshore interfaces.

Finnish offshore wind grid study: engagement scope

Assessed two offshore wind farms and their 400 kV Fingrid connection for a confidential Finnish customer in 2023.

Tyra satellite maintenance campaign: engagement scope

Worked with Muehlhan on Total’s Danish COPSAT programme, 2020–2022, covering maturation, risk/SIMOPS planning, permits, isolations and mechanical/electrical work on unmanned satellites.

DanTysk DT64 cable repair: engagement scope

Carried out 33 kV repair work for Vattenfall/Energinet in 2021, including cable diagnostics, post-termination testing, switching and offshore logistics.

Total Danish SECE maintenance: engagement scope

Supported safety and environmental critical equipment on Danish assets from 2007; the November 2020 case describes annual campaigns and assigned teams.

PBS UK general maintenance and operations: engagement scope

Contributed to the Ponticelli/Bilfinger/Semco consortium’s Total UK maintenance and operations programme, initially 2020–2025. The 2025 annual report confirms an extension.

Balder maintenance support: engagement scope

Supported Vår Energi’s Norwegian Balder asset from 2014, including compressor, thruster, generator, welding, hull and turret work described in the 2019 case.

Culzean EIT hookup: engagement scope

Delivered electrical, instrumentation and telecom hookup support for Maersk Oil’s UK Culzean development during 2017–2019 from the Aberdeen organisation.

Hornsea 1 telecommunications: engagement scope

Telecom EPCI, testing, supervision and commissioning for Bladt/Ørsted across three substations and a reactive-compensation station during 2016–2018. The dedicated case gives 2016–2018, while the parent telecom page gives 2016–2019.

Kriegers Flak fibre communications: engagement scope

Delivered a fibre interlink between two platforms for Vattenfall in 2017–2018, including twelve cabinets within a five-month package.

Horns Rev 3 water-mist protection: engagement scope

Supplied compact nitrogen-driven low-pressure water-mist systems for two diesel-generator rooms for HSM/Energinet in 2015–2016, designed in Australia and produced in Denmark.

Nordsee One electrical EPCI: engagement scope

Delivered electrical EPCI for Bladt/Innogy’s 332 MW offshore wind substation in 2015–2016; the case describes a 1,890-tonne topside.

Dominion turbine sea fastening: engagement scope

Fabricated and installed approximately 1,600 tonnes of sea fastening for 14.7 MW turbine transport in Bergen during 2024–2025.

Tyra shutdown and idle mode: engagement scope

Supported Total’s Danish Tyra shutdown in 2019–2020 with temporary generators/tanks, radio links, well isolation, SCADA/ESD and walk-to-work interfaces.

Greensand pilot CO2 handling: engagement scope

Engineered the liquid-CO2 pumping and container-locking package for the Greensand pilot in 2022, with Esbjerg fabrication planned in the project announcement.

Topsoe Herning factory package: engagement scope

Awarded electrical and mechanical work for Topsoe’s Herning plant in October 2023, with a planned 12–14-month delivery period.

UK offshore PLC support: engagement scope

Provided PLC support to a confidential UK operator from 2010, described as ongoing in May 2025 with a thirty-minute response and four-hour office attendance under that contract.

UK power-management migration: engagement scope

Migrated a confidential UK customer’s Siemens PLC/HMI power-management system during 2022–2024 using reverse engineering, simulation and factory testing.

West Elara SCR package: engagement scope

Developed SCR work for Seadrill’s Norwegian West Elara from 2024, covering four CAT C280 engines rated 3,463 kW each with H+H/Danfoss MES interfaces.

Linus SCR installation: engagement scope

Supported Odfjell’s Norwegian Linus SCR project from February 2024 for four CAT C280-12 engines rated 3,460 kW each.

West Phoenix SCR engineering: engagement scope

Prepared 2023 FEED and a 2024 DNV submission package for Seadrill’s West Phoenix, covering six Wärtsilä 12V32 engines rated 6,285 kW each.

Valaris DS15 and DS17 reactivation: engagement scope

Supported SCR reactivation testing and commissioning for two Valaris drillships during the second and third quarters of 2023 in Las Palmas and Brazil.

Valaris JU291 SCR concept: engagement scope

Developed a 2023 SCR concept for Valaris JU291’s four Wärtsilä 8L26 engines in the UK.

Valaris JU123 SCR retrofit: engagement scope

Integrated SCR for six CAT 3516 engines with CAT Zeppelin during 2021–2022 in the UK/Netherlands. The case records an 89–95% NOx reduction.

Dogger Bank A private mobile network: engagement scope

Delivered a 2022–2023 offshore mobile network for SSE/Equinor’s project, using Ericsson radio access, Athonet Release 16 core and four SOV customer-premises units.

Ørsted UK telecom service framework: engagement scope

Provided telecom maintenance and support under the historical 2020–2024 UK framework, including cybersecurity patches and licences.

Northwester II telecom EPCI: engagement scope

Delivered offshore-substation and onshore telecom EPCI for Bladt/Parkwind during 2018–2020.

Karish FPSO telecommunications: engagement scope

Supplied twenty telecom systems for TechnipFMC/Energean in Singapore during 2018–2019.

Tyra telecom package: engagement scope

Delivered thirteen telecom systems across six platforms and bridges for McDermott/Total during 2018–2019.

Siri and Nini microwave links: engagement scope

Delivered a 2019 INEOS communications upgrade with two Ericsson MINI-LINK 6363 links, Cisco SIP/SCADA interfaces, FAT and Ex enclosures.

Floatel Endurance yard award: engagement scope

Awarded a Hanøytangen yard stay in December 2025 for planned first-quarter 2026 work on thrusters, hull, accommodation and SCR/DOC systems.

MOSS molten-salt demonstrator: engagement scope

Hosted the Hyme-led MOSS demonstrator inaugurated in Esbjerg in April 2024. Controls work during 2023–2024 included PLC/HMI, drives and high-voltage supervision from the Aberdeen team.

Data Insight dashboard development: engagement scope

Developed a browser-based view of asset measurements, alarms and anomalies, presented in 2022.

AI-assisted corrosion inspection: engagement scope

Worked with Zevit, Aalborg University, MMSurvey and Energy Cluster Denmark on image-based corrosion assessment, presented in 2022.

XR remote-assistance development: engagement scope

Developed offshore remote-assistance approaches using HoloLens/XR with Virsabi, presented in 2022.

Arctic-vessel FEED: engagement scope

Executed the FEED 1.2 contract through Danske Flådeskibe for five Arctic naval vessels in 2025; this was design work for the future fleet.

Kalundborg CO2 Hub FEED: engagement scope

Performed front-end engineering and design for Ørsted’s Kalundborg CO2 Hub during the 2025 programme; the engineering engagement does not establish a completed capture facility.

UK integrated control and safety support: engagement scope

Awarded a three-year contract from February 2026 to support more than twelve industrial control systems across eight UK offshore/onshore assets. Aberdeen teams maintain, modify and rationalise control and safety systems, with two optional one-year extensions.

INEOS Danish North Sea service framework: engagement scope

Agreed onshore and offshore services for June 2026 to May 2031, with two optional one-year extensions. Work includes technical personnel, rope access, planned maintenance, NORM assignments, rental equipment and vessel technicians.

BC125/BC150 Ex ambient limits

IP66/67; −40 to +55 °C for T6, −40 to +60 °C for T5 or −40 to +70 °C for T4, under the selected Ex configuration.

BC125/BC150 construction

BC125: 316L stainless steel, 4.5 kg; BC150: GRP, 3.8 kg; borosilicate glass 3.3 lens.

BC125/BC150 electrical configurations

12–48 V DC, 12–48 V AC 50/60 Hz or 100–240 V AC 50/60 Hz, selected by model; LED 5/10 W, Xenon 5/10/15 J and a disputed 20/21 J ordering variant.

BC125/BC150 light output

Clear-lens true intensity: Xenon 5 J 109 cd, 10 J 293 cd, 15 J 395 cd; LED 5 W 128 cd or 10 W 312 cd. Colour factors are red 0.15, amber 0.51, blue 0.12, green 0.49 and clear 1.

BC125/BC150 light-source life

Xenon emission falls to 70% after eight million flashes; LED catalogue life exceeds 50,000 h without reduced luminosity. These are source/model figures, not a system warranty.

BC125/BC150 cable connections

Four M20 entries; M25, 1/2-inch NPT and 3/4-inch NPT are options. Terminals 0.5–2.5 mm² (22–14 AWG); glands and blind plugs excluded.

BC125/BC150 product approvals

Nemko 13 ATEX 1561X and IECEx NEM 13.0030X; gas zones 1/2 and dust zones 21/22 under the selected temperature class. Product approval does not certify Semco operations.

SD125/SD150 sound configuration

59 selectable tones; up to 115 dB at 1 m depending on tone/configuration; adjustable 5–25 W sounder consumption with 20 W factory setting.

SD125/SD150 Ex and environmental scope

IP66/67; T6 −40 to +55 °C, T5 −40 to +60 °C, T4 −40 to +70 °C. Nemko 13 ATEX 1562X and IECEx NEM 13.0032X, gas zones 1/2 and dust zones 21/22.

SD125/SD150 construction

SD125: 316L enclosure/bracket, 6.2 kg; SD150: GRP enclosure and 316L bracket, 5.4 kg.

SD125/SD150 supply and terminals

12–48 V DC, 12–48 V AC 50/60 Hz or 100–240 V AC 50/60 Hz by configuration; two M20 entries with alternatives optional; 0.5–2.5 mm² terminals.

BA-56EExeN(T) speaker

6 W; Nemko 10ATEX1050, Ex de IIB+H2 T6 Gb. Certified/specification-matched entries and 2–3 Nm lid torque are conditions of installation.

CAREEX catalogue naming conflict

Heading CAREEX-36(T) differs from the CAREEX-6T 6 W 100 V ordering line. Nemko 10ATEX1058X / IECEx NEM 11.0031X are printed for the heading; identity must remain variant-specific.

DSP-15EExmN(T) configuration

15 W, 100 V line, group IIC, IP67, stainless bracket and two M20 glands in the listed configuration; 2 Nm lid torque and matched glands/plugs preserve the stated protection.

DSP-25EExmN(T) gas-group conflict

Catalogue heading and ordering line specify group IIB; the adjacent Ex code includes IIB+H2/IIC T5 Gb, Nemko 10ATEX1053. Do not treat all DSP25 variants as group IIC.

HP15(T) transformer taps

Combined 70/100 V transformer; selectable nominal taps 15, 7.5, 4 or 2 W.

H66 horn-speaker rating

Aluminium, IP67; 25 W rated / 30 W maximum, 109 dB at 1 W/1 m, 300–7,000 Hz effective range, diameter 217 × 245 mm; 8 or 20 ohm variants.

SL125/SL150 status-light configurations

Up to five beacons on a 316L frame; SL125 stainless housings, SL150 GRP housings. One beacon can be replaced by a push button or junction box on request.

SL125/SL150 protection

IP66/67; T6 −40 to +55 °C, T5 −40 to +60 °C or T4 −40 to +70 °C; Nemko 13 ATEX 1566X / IECEx NEM 13.0036X for the selected assembly.

SL125/SL150 configured weights

SL125 A/B/C/D: 10.2/15/20/24.50 kg; SL150 A/B/C/D: 10.2/15/20.2/23.90 kg, respectively.

SB125/SB150 Ex combination units

316L or GRP housing with 316L bracket/frame; 59 tones, up to 115 dB at 1 m, 5–25 W adjustable sounder. LED/Xenon beacon and supply voltage are selected separately.

SB125/SB150 Ex protection

IP66/67; T6 −40 to +55 °C, T5 −40 to +60 °C or T4 −40 to +70 °C; Nemko 13 ATEX 1566X / IECEx NEM 13.0036X, gas zones 1/2 and dust zones 21/22.

SB combination-unit mass

SB125-1 and SB150-1: 8.0 kg each. SB125-2/3/4/5: 11.90/16.70/20.00/25.10 kg. The SB150-series table repeats SB125 identifiers, so those larger-assembly weights are not assigned to SB150.

NSF100 conventional alarm

9–32 V DC, nominal 24 V; 32 tones, tone-dependent 70–114 dB(A), 0.5–15 cd beacon, 10–45 mA depending on tone/flash selection, terminals 0.28–2.5 mm².

NSF100 addressable alarm

17–40 V DC loop; eight tones, tone-dependent 70–100 dB(A), 5–15 mA depending on tone/flash selection; beacon 0.5–7 cd with a 15 cd option at higher current.

NSF100 enclosure and alarm stages

V0 ABS body and V0 polycarbonate lens; IP54 or IP65 according to base/configuration, two-stage alarm and up to 15 dB volume attenuation.

CP/PB125/135/150 interfaces

CP break-glass and PB push-button variants; one or two changeover contacts and optional 4–20 mA PLC/ESD/DCS interface, line detection and LED indication. PB supports self-reset or key-release options.

CP/PB125/135/150 environmental ratings

IP66/67; T6 −40 to +55 °C, T5 −40 to +60 °C or T4 −40 to +70 °C; gas zones 1/2 and dust zones 21/22 under model-specific approval.

CP/PB125/135/150 resistive-load contact ratings

11 A at 125/250 V AC 50/60 Hz; 6 A at 30 V DC, 0.3 A at 125 V DC and 0.6 A at 250 V DC as printed. Minimum 5 V DC / 10 mA; 10 A gG short-circuit protection. The unusual DC ordering is retained as a source-specific specification.

CP/PB construction and cable entries

125 series: 316L; 135/150: GRP. Four M20 entries on 125/150 and two on 135, with other threads optional; terminals 0.5–2.5 mm².

CP/PB configured weights

CP125 4.9 kg, CP135 4.9 kg, CP150 4.2 kg; PB125 4.9 kg, PB135 2 kg, PB150 4.2 kg, per catalogue tables.

KAC WCP3 environmental and mechanical scope

Operating/storage temperature −25 to +70 °C; IP67, PC/ABS body, 350 g. Cable termination 0.5–2.5 mm²; WCP3A offers normally open/closed contacts, with two terminal blocks for changeover.

EXDE adaptor/reducer material scope

Brass CZ121, stainless steel 316, aluminium 6082 or mild steel EN1A in the brochure; stocked order-code material choices are brass, 316 and aluminium, with other materials on application.

SAX/SRX/SAVX thread configuration

Male and female choices M16–M75, NPT 1/2–2 1/2 inch and PG7–PG48; SAX adaptor, SRX reducer or SAVX 90-degree adaptor. Matching combinations depend on the ordered design.

EXDE adaptor/reducer protection

−50 to +100 °C, IP66/IP67/IP68 to 2 m in the described sealed configuration; SIRA 00ATEX1094X / IECEx SIR 12.0016X. Sealing and installation conditions apply.

Dome-head stopping plugs

Ex d/e; M16–M75 metric table, 16 mm thread length and 21.5 mm total length; captive O-ring, IP66/IP68 to 2 m and −50 to +100 °C for the specified materials/seals.

PH-E hex-head stopping plugs

Ex e, IP64, no O-ring; M16–M75 table with 10 mm thread length and size-dependent 14.5–16 mm total length, −50 to +100 °C.

Type A/B stopping plugs

Ex d, IP64, no O-ring; metric M16–M75 table has 17 mm total length; selected PG Type B entries have 16 mm total length. Type A tightens externally and Type B internally.

DP-E metallic breather-drain temperature

Metal body −60 to +200 °C without O-ring; HDPE filter −50 to +85 °C. Final permissible range is limited by the selected body, filter and interface seal together.

DP-E/DP-E4 interface seal limits

Nitrile −30 to +80 °C; EPDM −50 to +100 °C; neoprene −40 to +80 °C; Viton −20 to +180 °C; silicone −60 to +180 °C; fluorosilicone −60 to +130 °C. These seal-only ranges do not override the body/filter limits.

DP-E4 nylon breather-drain temperature

Glass-filled nylon body −30 to +90 °C; HDPE filter −50 to +85 °C; standard nitrile seal −30 to +80 °C. The installed assembly must satisfy all three limits.

DP-E/DP-E4 installation protection

IP66 when fitted according to manufacturer instructions; ITS16ATEX101338X / IECEx ITS 16.0014X for Ex e and dust-tight configurations.

DP-E metallic dimensions

M20/M25/M32: minimum overall length 23 mm and thread length 10 mm; across flats 28.60/34.90/41.30 mm respectively. NPT 1/2, 3/4 and 1 inch: minimum overall 28 mm and thread 15 mm, with the same respective across-flat sizes.

DP-E4 nylon dimensions

M20/M25: minimum overall 34 mm and thread 17 mm, across flats 28.60/34.90 mm respectively. NPT 1/2 inch: overall minimum 32 mm, thread 15 mm, across flats 34.90 mm. Metric coding example instead says 15 mm thread; this discrepancy remains unresolved.

CMP 781D/781E operating limits

Metal variants −60 to +130 °C; nylon 781E −20 to +60 °C. 781D IP66 requires CMP sealing accessories; 781E IP66 uses the interface O-ring and locknut.

CMP 781D enclosure limit

Up to 30 litres for group IIB or 2.5 litres for group IIC; 781E has no enclosure-volume restriction in this catalogue.

CMP 781 thread dimensions

M20×1.5 and M25×1.5: minimum 15.0 mm thread; 1/2-inch NPT 19.9 mm and 3/4-inch NPT 20.2 mm minimum thread. Protrusion 12.7 mm for these configurations.

CMP 781 component certification

CML 18ATEX1330U / IECEx CML 18.0187U / CML 21UKEX1241U are component certificates; they do not by themselves approve an assembled enclosure.