Havsil: a short submarine cable linking Norway and Denmark
The Havsil submarine cable is a 120 km fiber-optic system connecting
Kristiansand in Norway to
Hanstholm in Denmark. Owned by Bulk Infrastructure, it is listed as in service and was recorded as ready for service (RFS) in 2022 according to GeoCables data. The cable’s short distance reflects its role as a direct link between these two landing points, bypassing longer routes through other submarine cables in the region.
What makes Havsil intriguing is the limited amount of publicly disclosed information about its technical specifications, such as design capacity, fiber pairs, and supplier details. This lack of transparency contrasts with the detailed documentation available for many other cables, leaving room for speculation about its underlying technology and operational characteristics.
Quick facts
| Cable name | Havsil |
| Length | 120 km |
| Ready for service | 2022 (GeoCables database) |
| Owners | Bulk Infrastructure |
| Status | In service |
| Design capacity | Not disclosed |
| Fiber pairs | Not disclosed |
| Supplier | Not disclosed |
| Technology | Not disclosed |
| Landing points | Kristiansand (Norway), Hanstholm (Denmark) |
Route
Havsil connects Kristiansand on Norway’s southern coast to Hanstholm on Denmark’s northwestern coast. This route spans the Skagerrak Strait, a critical maritime corridor that separates the two countries. Kristiansand serves as a hub for multiple submarine cables, including
Havfrue/AEC-2,
IOEMA,
IOEMA-1,
N0r5ke Viking 2,
Norfest, and
Skagerrak 4, making it a strategic landing site for regional and international connectivity. Hanstholm, while less prominent in the submarine cable network, provides a direct entry point into Denmark’s fiber infrastructure.
Why it was built and what it carries
Havsil was likely constructed to enhance connectivity between Norway and Denmark, providing a dedicated and low-latency link across the Skagerrak Strait. The cable’s relatively short length suggests it is optimized for regional traffic rather than long-haul intercontinental data transmission. It may serve as a supplementary route to existing cables in the area, offering redundancy and additional capacity for data exchange between the two countries.
History: what can be established
GeoCables data records Havsil as ready for service in 2022, and it is currently listed as operational. If industry sources or public records suggest a different RFS year, this discrepancy has not been surfaced in available documentation. Possible reasons for such conflicts in submarine cable timelines include delays in construction, differences in reporting standards, or updates to operational status that are not uniformly communicated.
Capacity and technology
Publicly available data does not disclose Havsil’s design capacity, the number of fiber pairs, or the supplier responsible for its construction. Without operator documentation, attributing specific technological features or performance metrics would be speculative. As a modern cable, it is reasonable to assume Havsil employs advanced fiber-optic technologies, but the specifics remain unknown.
Latency: the physics
The theoretical one-way latency for light propagation over Havsil’s 120 km length is approximately 0.6 milliseconds, with a round-trip time (RTT) floor of about 1.2 milliseconds. However, real-world latency measurements are significantly higher due to additional factors such as land-based network segments, terminal equipment processing, and routing.
GeoCables live measurements, which capture the full internet path rather than the cable itself, show Kristiansand-to-Hanstholm latency ranging from 12.6 ms to 13.3 ms (average), and Hanstholm-to-Kristiansand latency ranging from 21.3 ms to 36.9 ms (average). These figures highlight the impact of terrestrial infrastructure and network conditions on end-to-end latency.
Redundancy: what happens if it breaks
If Havsil were to experience a fault, several alternative cables at Kristiansand could provide redundancy, including Havfrue/AEC-2, IOEMA, IOEMA-1, N0r5ke Viking 2, Norfest, and Skagerrak 4. These systems span diverse routes and offer varying levels of capacity and connectivity. Standard industry practices for submarine cable repair, such as deploying specialized cable ships and conducting underwater inspections, would likely apply to Havsil in the event of a disruption.
Bottom line
- Havsil is a 120 km submarine cable connecting Kristiansand (Norway) to Hanstholm (Denmark).
- Owned by Bulk Infrastructure, it was recorded as ready for service in 2022.
- Technical specifications such as design capacity, fiber pairs, and supplier are not publicly disclosed.
- Theoretical latency is approximately 1.2 ms RTT over the wet segment, but real-world measurements are higher.
- Kristiansand hosts multiple alternative cables for redundancy.