Battery power for cpap?

[lazydays]

I am going sailing in a few months and will be sleeping on the boat. I've become very attached to my cpap machine though and I don't want to go without it. I'm told I cannot be guaranteed a 110 outlet. There "may" be a cigarette outlet but again no guarantee. I'm wondering if I can just buy a battery pack? I'm googling but not seeing a commercial product yet. Any recommendations would be great.