Mastervolt has one: IVET-D 3.5 kVA/16A (toroidal) - Multi tap « Isolation Transformers | Mastervolt. The worlds leading brand in maritime, mobile and solar energy solutions.
Try Googling for marine power transformer 120 230
Marinco makes an adapter from 30A US to 16A Euro. It wasn't easy to find and I expect you'll have to order it. You might have best luck engaging MAYS ( firstname.lastname@example.org
) ahead of time - they may be able to have it for you when you arrive if you can't find it in the US. Perhaps there is a 50US - 16Euro or 50US - 30Euro adapter as well? Sorry - I'm not as familiar with that stuff as the 30s.
I used a garden variety tool transformer (the sort that MAYS sells) in the UK and Azores. It was rated at 10A continuous (20A on the 120V side). I adjusted my battery charger so it would not draw too much and switched off the water heater. Other AC loads are just incidental chargers for phones and such. My water heater is pretty well insulated so by switching off the battery charger for a few hours each day and turning on the water heater there was hot water for a day or so.
Have you read Jack Tyler's information on cruising Europe? I recommend it highly. Whoosh
In addition to electrics, spend some time thinking about water. I have ended up with a small bag of adapters and a pre-filter that have served me well. Read Jack's bit on water. I found some very useful adapters at Home Depot and Lowes that connect US-spec hoses to garden soaker hose that work well for Euro-dock hoses (which often have no termination on them at all). If you get a pre-filter (which I am pleased to have) I suggest a practice of disassembly to dry the cartridge after each use to avoid nasty growth. I soak mine in vinegar after use before drying for storage. YMMV.