In Poland, there are two institutions dedicated to marine accidents investigation - State Marine Accidents Investigation Commission (SMAIC) and Maritime Chambers.
They mainly examine marine accidents and casualties which happen in Polish territorial waters, (accidents of Polish-flagged vessels, boats and yachts are examined regardless of where they took place).
SMAIC is a governmental agency composed of experienced officers and master mariners. It focuses mainly on technical and navigational factors which led to the accident and does not rule on anybody's personal liability.
SMAIC reports usually contain extensive photographic documentation, maps, AIS charts - and, if necessary, any other findings regarding the accident which may be necessary. Interested parties rarely have the opportunity to submit comments, therefore SMAIC reports are generally based on findings of their inspectors. For this reason, SMAIC reports must not be used as evidence of anybody's liability in further civil and criminal proceedings as well as in the proceedings before the Maritime Chambers.
In my opinion, however, there are no obstacles to use these reports in the above mentioned proceedings as statements of facts of objective nature (for instance such as speed, position of vessel, weather conditions, technical condition of the vessel prior and after the accident, documentation of damages etc.) - especially in view of the fact that SMAIC is impartial and the Polish law generally provides for a presumption that the statements of the official document (including but not limited document issued by public authorities) are true.
SMAIC runs its own website where all its reports are published in Polish and English and are available to anybody who is interested - pkbwm.gov.pl
Maritime Chambers (one in Gdynia and one in Szczecin plus Appellate Maritime Chamber in Gdynia) are quasi-judicial institutions associated with the Regional Court in Gdansk and Regional Court in Szczecin. They examine accident cases in the hearings (very similar to court hearings) presided by a judge of the respective regional court (with two assessors who are usually experienced masters or senior officers / chief engineers). The Maritime Chamber has its own procedure (with supplementary application of the Polish Code of Criminal Procedure) which means that many actions of the Chamber are taken ex officio.
The preparatory proceedings before the Maritime Chamber are conducted either by the investigative inspector of the Chamber or by maritime administration bodies. In the event that an incident takes place on a ship that is to leave Poland in a short time, it is important to secure all evidence such as hearing of witnesses, photographic documentation or records from the ship's recorders. Otherwise, it may not be possible to recover this evidence later.
All parties involved in the proceedings have a status of "interested parties" - there are no defendants or accused parties and no prosecutor (there are investigation inspectors and the delegate of the Ministry of Infrastructure but they do not have the power to accuse anybody). The interested parties may submit evidence of any type and remarks to other parties' evidence, ask the questions to the witnesses and other interested parties.
Unlike the SMAIC the Maritime Chambers may determine the liability for the accident and take disciplinary steps towards Polish officers and seafarers involved in the accident (it is rather impossible to take disciplinary measures against non-Polish officers and seafarers). Maritime Chambers do not have competence of civil and criminal courts and do not solve any financial disputes between the parties. If it is not entirely possible or completely impossible for the Maritime Chamber to determine the reasons of the maritime accident this information is explicitly stated in the decision.
The decision of the Maritime Chamber is not a judgement and does not bind Polish courts. It, however, in court proceedings, the official findings of the Maritime Chamber will will be serious evidence.
Other functions of the Maritime Chambers is registration of Polish vessels (and mortgages) and accepting of the sea protests but this is completely different story.