On certain missions you will come across gunboats. These, like any Axis vehicle, can be destroyed as long as you know it’s weak points.
The issue you have is that they can be fast moving, so you need to lead your shot a little. However, if you are patient they will generally stop at some point, leaving an easier shot.
Gunboats are heavily armoured and have a top mounted heavy machine gun which will rake your position with withering fire. You also cannot get a shot off at the shooter as he is heavily protected by armour.
How to destroy a gunboat in Sniper Elite 5
To destroy the gunboat you need to hit the fuel tanks at the rear. You can pick them off with your scope but there are also better weapons to use that will cause more damage. Once in your sights the weak points will glow red, highlighting that that is definitely the part of the gunboat you want to aim at.
If you get too close to the waterline the boat will return heavy fire on your position so try and shoot from cover.
There is a plu point to this however, in that if you do manage to draw fire from the crew, the boat will always stop in order to try and hit back at your location. This will provide the perfect opportunity to unload a few heavy weapons at the craft and hopefully send it to Davy Jones’ Locker.