Solar panels HATE shade and just a little has a dramatic effect.
On Waiata we have 5 X LG415Watt bifacial panels that are really good and especially good with lower sunshine levels.
BUT the other day I found, whilst cleaning connectors and monitoring each panel, that even my own arms shadow, in fact, just my hand, on a panel would reduce its output by nearly 80%.
The biggest source of shade on a moored boat is the Mast and boom. You can’t do much about the mast but you can do alot about the Boom.