We planned to insulate our wheelhouse roof more, the wheelhouse suffered from condensation leading to damp, which started mould growing.  The 24mm Vekaplan didn’t seem to be enough so we got a quote for a tarpaulin cover and then costed 50mm of insualtion to go under it. However the radar was mounted directly to the roof and the manual showed that this was not ideal because the vertical beam angle of the radar signal can then ‘bounce’ off the roof. The roof is plastic but does have aluminium rails. Lawrence designed (Google sketchup) and built a small radar mount out of Vekaplan, the same material as the roof, to raise the radar by 20cm. The problem is shown on the left with the mount design and the finished product to the right.

Even before putting insulation on the roof we suspected that mounting the radar directly to the roof was not ideal. Below left is a radar picture from our mooring before raising the radar and to the right is 2 hours later with the radar raised. More buoys and boats show up aft of Waterdog when the radar had been raised above the roof (right) than before. This was particularly the case for the buoys and posts that were close behind Waterdog’s stern. There shouldn’t be any difference looking forward as the radar is close to the front of the wheelhouse roof.

So now we still have to decide if we can have aluminium covered insulation or bare plastic panels, I think we’ll go with no aluminium.