All fine if you're moored near a laundrette, which I expect you are. However laundrettes are becoming scarcer as the demand for them continues to drop, many boaters won't have one within reasonable distance, and may not have transport (car or public) to easily get to one. In that case an onboard washer -- or washer/drier (no condensation!) if you can afford the power consumption -- makes a lot of sense, if you have space for one.

We have an automatic Candy washing machine on Kelpie and I find using the 30% setting it takes less than half an hour and like Mrs Cuthound, it does as good a job as our machine at home. We don't live aboard and I only do a washing on good drying days. I hang the clothes under the cratch on a thing which I think is supposed to be hung outside caravan windows.