After what seemed like months of work, well actually it was, the time had come to insulate. It was a slight rush as I had booked the team and there was still loads to do. The thing is with sprayed foam insulation is it goes everywhere. So whatever you don't want foamed you have to cover with tape and plastic. All the faces of the battens are covered in parcel tape leaving suitable tags for a gloved hand to pull it off. Plastic was used in the bilge areas, windows and such like.
It is only necessary to foam down to the waterline or a little below. The warmish waters of temperate climates will insulate the bottom. In more northern waters it will be preferable to insulate the entire hull. The only other time you may wish to insulate the bilge area is if your mooring dries out and there is no water around to insulate.
I used Websters and found the crew rather good. Get a firm to spray and cut back. There will always be an amount of cut back. Where the foam is over applied and is too thick. If the crew have to cut back then they will be more careful in the spraying. Ventilate the boat for a day or two to get rid of the chemicals coming out of that foam.
The foam is in two parts, mixed at the spray nozzle which needs to be about two feet from the surface. It is sometimes difficult to get "behind" things like angled steel returns. You can see in the above photo some uneven beads of foam next to the curved frames. I used the professional spray foam in cans to work into the shy places. I did this on all the frames and in a few other awkward to get at places. You can see there is no foam on the from edges of the battens. When the foam has been sprayed the tape is pulled off together with any overspray. Any foam above the level of the battens is cut back using a rip saw used on its side. Just like taking slice from and uncut loaf!