Hi All - new to Forum but have already found it very useful.
Just did 1800 miles UK-Canaries on our new (to us) 42 DS 2007. When she's rolling there are a lot of loud creaking noises from the cockpit floor around the area of the aft bulkhead.
Upon inspection there is movement of the bulkhead at the bottom of the access hole behind the headboard where two parts of the bulkhead are joined - but this doesn't appear to account for all the noise. There is no visible movement of the bulkhead, but it does seem to be where the noise is coming from and this is where the rudder shaft is secured to, so is presumably taking the side-side pressure on the rudder shaft as she rolls.
I believe most boats at one time or another have these cracking noises mostly from around the bulkhead areas and is normally due to the boat flexing and causing the wooden structure to move, resulting in wooden joins grinding against one another. I have experienced it on cheap and also very expensive boats and it can be very loud and quite annoying. Sometimes it can be fixed by the simple task of wedging a piece of folded card between a join or the addition of flexible silicon filler. The most frustrating exercise is in hunting down the precise location of the offending noise. I would be surprised if it was your rudder, I would have thought that any wear in that region capable of making such a load noise would cause a leak, which would be obvious to locate.
Congratulations on owning such a great yacht. We have a 2008 SO42DS with a teak floor in the cockpit. I experience exactly the same creaking as you describe when rolling at anchor. It is quite loud and persistent and at first does create some anxiety leading to investigations regarding the source of the sound.
We have had the boat since 2012 and it has done quite a lot of miles. We have lived on her for over 6 months of each the last 3 years.
I think it is the teak flooring and have simply become accustomed to the creaking. It is a part of her personality and reminds me that maybe I should try to find a less rolly location😂.