When a Crew Transfer Vessel (CTV) approaches an offshore wind turbine, it may look as if the vessel is deliberately pushing its bow against the structure instead of simply stopping nearby.
This is not a mistake. It is a common personnel transfer method known as Push-on Transfer.
The CTV uses continuous forward thrust to press its bow against the turbine’s Boat Landing, creating a controlled contact point so personnel can transfer onto the access ladder.

Why Not Just Stop Beside the Turbine?
Because a vessel at sea never stays perfectly still.
Wind, waves, and currents constantly move the CTV forward, backward, sideways, and vertically. If the vessel simply floated beside the ladder, the distance between the bow and the turbine could change quickly.
During Push-on Transfer, the vessel maintains forward thrust against the Boat Landing’s bumper bars. The bow is usually fitted with a suitable fendering system to manage the contact.
The purpose is not to make the vessel completely motionless, but to prevent it from drifting away from the transfer point.

The Vessel Still Moves—So How Do People Transfer?
Even while pushing against the structure, the CTV can still move up and down with the waves.
Personnel therefore transfer only when vessel motion and sea conditions are within safe limits. They step from the bow onto the turbine’s access ladder, connect to the required fall-protection system, and climb toward the working platform.
Traditional CTV transfers are particularly sensitive to sea state, which is why every vessel and wind farm has defined operational limits.

Why Does the CTV Not Damage the Turbine?
Push-on Transfer is not a high-speed collision.
The vessel approaches at controlled speed and then applies steady thrust. The Boat Landing is specifically designed to receive CTV contact loads, while the vessel’s bow fender helps manage impact and friction.
However, unexpected waves can still create rapid vessel movement, so transfer operations must stop when conditions exceed safe limits.

Push-on Transfer vs Walk-to-Work
Both methods move personnel onto offshore wind turbines, but they work differently.
 ▪ A CTV Push-on Transfer uses the vessel’s bow, Boat Landing, and access ladder.
 ▪ An SOV Walk-to-Work operation typically uses Dynamic Positioning and a Motion Compensated Gangway to create a direct walkway to the turbine platform.

So when a CTV appears to be “pushing” against a wind turbine, it is actually using controlled thrust and a purpose-built Boat Landing to maintain a safe transfer interface in a constantly moving sea.


References:
 • Guide to an offshore wind farm | An informative resource for offshore wind (Image source)
 • IMCA: Crew transfer vessel (CTV) personnel transfers
 • IMCA: Standardised boat landing research report