With no experience of stoves on boats to back up any advice, but lived in many houses with coal/wood stoves,  however there are a few things you should check if the sooting is excessive.

Is the flue clean and clear this is vital for safety, poor combustion from a blocked/ partially blocked flue and poor ventilation will cause sooting as the fire does not get enough oxygen and burns at a too low a temp to combust all the gases etc these then cling to the glass and flue in the form of tarry deposits.

The fuel you are using is it the correct fuel for your stove ( there are numerous threads on the internet regarding mult-ifuel / wood burners and solid fuel stoves and the very best fuel to use for each)

Avoid softwood/Coniferous/pine ( pallets are made of this and are often seen as a cheap fuel source)  as a fuel these tend to have a high resin content and burn a lot dirtier with lots of smoke and creosote that coats the flue and maybe the glass, than hard woods (I read that ash is a nice clean wood to burn as it smokes less and burns nicely)

Agree with all the above.

On a Squirrel burning wood only,

Hardwood with less than 16% moisture
When burning wood only close the bottom air vent and open the top one about two complete turns

Burning solid fuel

Open the bottom air vent and control the temp that way. Top vent needs to be open about one turn to keep air going a across the glass.

Most stoves will smoke if you try to close them down too much. They are not designed to smolder overnight. They need a good fire to burn cleanly.

The best way to clean the glass is to use meths. Oh when the fire is out and the glass cold.

Hope that helps

GM

Good tip Paul.  Suede brush useful for removing soot.