Not sure if you have the split windows to the cabin? The side windows on later Bavaria's are in two pieces. (as ours) There is a joint between the perspex (plastic glass) which is about an inch wide and is filled with Sikaflex as part of the window bonding to the hull.
This joint has a 3 way bond (two edges and the cabin top). The perspex is held in position by a screw during production (making a hole)
When the screw is removed the joint is filled but the hole is not filled. There is no bond breaker between the cabin top and the Sikaflex at this point .
No mastic, sealant, or similar bonding agent can take being pulled in 3 directions when the boat and windows expand and contract as the temperature goes up and down. The dark windows also expand at a different rate to the white fibreglass deck sides.
This is a well documented known issue in the Facade and glazing industry where a non stick bond breaker is placed to allow the sealant to slide over the 3rd surface (ie the cabin top) but remain bonded to the window edges.
When the joint breaks, which it will at some point, water gets behind the sealant and through the hole Bavaria made and failed to fill in production.
We have had to take remedial action on Impavidus when she was just over a year old, and have seen at least 4 other boats with the same detail that fails.
Sika and Bavaria know about the issue. Sika's data sheet/technical bulletin makes a mention about it somewhere...
Water comes through the holeand runs down behind the inner detailing into the bilge at almost exactly this spot.
The splitting in the mastic/Sika is almost impossible to spot from the outside. But careful inspection sees the mastic de-bonded from the window edge.
This may be the cause of your hidden leak, it's worth a check...
Hope this helps.
Ant.
