Per 
SCP-xxxx at the Ijmuiden seaport.
Item #: SCP-xxxx
Object class: Keter
Threat level: Green
Special containment procedures: Due to the nature of SCP-xxxx, containment is exceedingly difficult.
Upon the appearance of SCP-xxxx, it is to be tracked until it eventually vanishes. All activity from SCP-xxxx is to be recorded. All radio transmissions from SCP-xxxx are to be intercepted.
If an SCP-xxxx-1 instance is sighted by unauthorized personnel, embedded Foundation agents are to declare the object a common aircraft. Should SCP-xxxx-1 be recorded, the footage is to be intercepted and destroyed. Any unauthorised persons who've viewed such footage are to be either detained or amnestisiced.
Description: SCP-xxxx is a self-propelled barge ship, lacking any identifying markings and absent of any crew. The deck of SCP-xxxx is concealed with large segmented coverings, which can and have been opened for various purposes.
SCP-xxxx manifests by appearing at seaports, invariably in very foggy or overcast conditions and usually at night, wherein it will stay for multiple days. After some time, SCP-xxxx will then vanish via simply disappearing. Any attempts to contact SCP-xxxx have invariably lead to it vanishing. To date, SCP-xxxx has never been directly observed disappearing.
SCP-xxxx is usually very docile
SCP-xxxx-1 is the general designation for rocket-propelled1 vertical take-off and landing (VTOL) crafts of various models, none of which have been identified as belonging to any human organisation, which occasionally and anomalously appear at around 10 kilometers altitude above SCP-xxxx, and then attempt to land on SCP-xxxx.
SCP-xxxx-1 instances only appear in similar conditions to those which SCP-xxxx appears in, making observation of SCP-xxxx-1 instances rather difficult. Along with this, despite being powered by what appears to be rocket engines, they make no noise. While an SCP-xxxx-1 instance attempts to land on SCP-xxxx, it will open up multiple of its coverings, revealing a landing platform, which will then be extended above the height of the craft. Once an SCP-xxxx-1 instance successfully lands on SCP-xxxx's2 landing platform, it is retracted into SCP-xxxx again, and then covered again.
Addendum: SCP-xxxx will occasionally broadcast short-wave radio, which contain messages relating to the current situation of the vessel. Listed below are a few, as well as their contexts.
R-xxxx-013 19/06/1999,
