I have just a question: in some sites I have seen that there is a special naval ensign for belgium. Does it mean that vessels should carry this marine/naval ensign?
I have used the Belgian St. Andrews cross-style naval ensign on my boats (I downloaded it from Warflag). But I believe Warflag have posted that in their colonial section without checking the facts (and I downloaded it without checking them too!). The design on their website dates I believe from the 1950s and is the current ensign.
Belgium had a Royal Navy until the 1860s, when they got rid of it in a cost-cutting measure. They still didn't have one at the outbreak of the Great War. I think around 1917 they belatedly decided it might be a good idea to have one after all, and started afresh. So any gunboat in Africa in the colonial period is likely then to belong to the
Force Publique I would imagine, and so would perhaps fly the flag of that organisation (yellow star on blue field) instead of the Belgian tricolour. Not sure. Did the
Force Publique use the tricolour at all? I fancy I've seen illustrations of them doing so, but they might be erroneous.
But that fancy Naval Ensign would certainly be out. Up until the 50s the naval ensign was the same as the state flag (i.e. black-yellow-red tricolour).