On 23 August 1705, head of the Swedish postal system, signed an instruction for Mattias Bruggeman, master of the post yacht Lotsman.
Bruggeman was ordered to set sail for Riga, but exercise great caution when approaching the coast. If no enemy was present he should proceed to the fortress Dünamünde. If the enemy remained in Courland he should not risk going up to Riga, but only take on board letters to the Royal army or to Prussia or Germany. He should then proceed directly to Königsberg and hand over the letters to the postmaster. After doing this Bruggeman should take letters to Riga. If they were not ready he should proceed to Pillau and wait for them there. Once everything was ready he should hasten to Riga and then to Memel or Pillau.
Bruggeman should be careful with other ships and not allow more than one to approch his vessel. His crew should always be ready to defend the ship. The Governor in Riga and the commander of the garrison at Dünamünde would assist him in every way.