I once took my parents-in-law for a sail out of Christchurch and they bought their dog along. Despite a nice day it had changed to typical British mid-summer by the time that we ended up slogging back against a tide that was beginning to ebb (took longer than expected as usual).
It was, at first, pleasant surprise when my frozen toes suddenly started to warm and come back to life. I soon realised why when I looked down to see Bracken the dog's back end directly above my foot! Those deck shoes were never the same again.
Dogs and boats seem to go together quite naturally. You should see mine nip across boats and even jump from bathing platform to bathing platform. She scares me witless when she insists on standing on the bow to catch the spray. As regards their toiletries, take em walkies first then they will have no problem with 8-12 hours just as they have no problem overnight at home. If you can train them to nip up the bow and 'do it' so much the better. I never could all mine seemed to prefer to wait.
We ussed to take our Dog out all the time and he (it or ox actually) refused to do his ablutions on teh boat. Instead he would stand on deck and look longingly at the shore until I gave up and rowed him ashore.
I hade to be careful though because when I got within spitting distance of the shore he would launch himself off the tender, clear the 50 yard gap in one lead and immediatly squat down 9Witha huge grin on his face)
I'm sure that eventually he would do it on the boat if we left him long enough but he would do it expecting to be beaten afterwards. After all, that's what would happen in that other home that did not move with the waves.
He did not like rough weather though and would end up spendingthe wole time ina semi crouched position, tring to use his little legs and suspension.
We put our Golden Retriever on board at 8 weeks and let her wander around. Started sailing with her at 6 months. Initially one of us gave her plenty of attention and these days if we have visitors on board we warn them to sit down fast as the dog always finds the best spot. She is not very happy under power and is very happy under sail. She flattens herself to the word WASH!!! and if she spots power boats comming too close flattens herself anyway. She is quite happy to go for 16 hours without a nature break so Lyme Bay presents no problems!!!! Just let your dog get used to the baot in their own time and when it gets a bit rough give them some attention until they get used to it. If you are in the Solent and see a battered old avon with a battered old helm and a loopy golden retriever....welcome to the early morning run ashore...