Foam spray attachment for Karcher

My boat was looking a bit grimy after the winter,purely from the dust in the air.
I bought a foam spray gun for the pressure washer,and 5ltrs of road grime detergent.
It covered the whole boat in about 5mins with thick foam.I left it for 10mins and blasted it off with the pressure washer.One of my neighbours thought I had bought a new boat
I got the road grime degreaser liquid,which also takes off polish and oil.
If I use it on the car,it will need to be wash and wax liquid after the wax has been blown off.
It was £10 for the gun,and £15 for the liquid.
The bottle on the gun has a 1ltre capacity,I only put 1/8" of liquid in the bottom of it,topped it up with water,and it did the boat and front downstairs house windows.
If anyone was thinking of getting one,I'd definately recommend it.

very interesting, I have a Karcher but have only ever used it with plain water.

Using on a vehicle needs care and the pressure turned down or it can remove the paint!