With our daughter, who was a March baby, we took her out the first summer with no trouble. The only real hassle was getting her in to a PFD for the trip out to the mooring, but that wasn''t too bad as she seemed to tolerate it well, all things considered.
In our experience newborns are easier than toddlers; at least they stay where you put them and don''t try and climb around when you''re heeling.
We had a portable car seat that we brought along. This snugged in nicely down below in a space between the table and the port settee, and the handle could be kept up to provide lateral stability. The motion of the boat generally put her to sleep pretty quickly. For feeding my wife could go down below with her, or we could come up with a bottle.
I had always figured to
rig up comething with a car seat and a seat belt from a car, but never really found the need for anything that fancy. A simple removable car seat that could double as a carrier did the trick.
Sleeping wasn''t a big deal either, we stuck her in the quarter berth which was mostly enclosed and put some cushions up to keep her from escaping forwards. Once she could sit and try and stand that become more problematic as she kept conking her head on the top of the berth. It was generally more trouble getting big brother to leave her alone though...
The only time it was more difficult was when she started getting restless down below and/or big brother started fussing AND the boat needed tending too. It''s one of the reasons we decided to get a new boat; the newer one is more friendly sailing short handed so one parent can manage kids.
We tend to tether the kids in the cockpit in addition to PFD''s. Of course last year when they were older and our daughter walking and being more mobile, the two kids were fully capable of getting into things, falling over, and irritating each other so you need more care in amusing them. My daughter HATES it when her big brother pulls on her tether...
The one other thing about sailing with babies is that the Rule of Accumulated Junk You Have to Schlep With Kids still applies if you plan to get off the boat anywhere but where you started. In other words, don''t forget the darned stroller! The stroller is actually kind of handy on shore, and a very good place to tuck/hang the kid''s PFD''s once they get on land.