Trying to make a choice between the two for a charter. Have chartered in the BVI multiple times. I am not looking for information about which bays or islands to visit. I am looking for real information on sailing conditions and which location would be better for a novice crew and a child (other than captain and mate). Is there a calmer time to visit the Grenadines? Are people likely to get sick because of the swells. I have read that swells are regularly 6-8 and winds of 20-25. What is the experience level for captain? Are most anchorages rolly or require double anchors? I will go to the Grenadines, just maybe not this trip.

The Grenadines are more of an open sea sailing experience when comparing it to the protected waters of the BVI. I am not sure I would want to go with a novice crew. We sailed in the BVI several times, and have switched over to the Grenadines as our preferred sailing destination due to it's beauty, lack of tourism, and the remoteness/nature of the area. Some anchorages are rolly, depending on conditions. Each time we have gone, we do have people who get sea sick, especially the first day.

Agreed. The first time I went was with one sort of experienced couple (me and my ex) and one inexperienced crew (one trip in the summer to the BVI).

We went in December, and it was a lot different for the crew than the calm waters of June BVI. He was sick most of the first part of the week, and the first leg, from St. Vincent to either Mustique or Bequia is usually, I find, the roughest part of the trip.

Having said that, Jim and I sailed in June for two weeks with no major issues, great sailing, only one squall, higher than BVI summer winds and beautiful sunshine most days.

If it were new crew, I would start in the BVI's and work your way through the SVIs before heading to the Grenadines.

If you're determined, June seemed like a much calmer month for sailing than December.

I think your multiple charters in the BVI's qualifies you and mate to step up to SVG. Sailing distances are longer but not extreme. For example, the cruising guide indicates it's only 8 miles from Blue Lagoon to Admiralty Bay. Longest distance I see is 16 miles is from Bequi to Canaoun – not much further than going to Anegada from North Sound. I have chartered there in summer and in fall (November). I liked November because businesses were open and conditions were excellent with winds around 15 kts. I only recall one rolly anchorage and that was at Mustique. Never used more than 1 anchor anywhere. I actually experienced conditions you described in the BVI’s last May (i.e. 20-25 kts). Just make sure you know where you are and the island you’re heading for is the one where you want to go.
Although I think SVG is a logical progression for the crew, I have other thoughts about your guests. If they haven’t been sailing anywhere in the Caribbean, they will think the BVI’s are just wonderful - I think they are too. Also, if someone isn’t feeling well you can get them to land and wellness in fairly short order in the BVI’s. I would also consider the cost and hassle of just getting everyone to SVG vs. the BVI’s so I would do some research and comparison in this area.
Bottom line – I think it would be less stressful on the crew and newbie guests to go to the BVI’s – they are going to love it. I would save SVG for just the experienced crew.
Fred

June and July are good times and you might get a few free days.
That being said after sailing both locations extensively in my opinion you are doing the newbies a disfavor but not taking them to the BVI first. Go to the Grenadines when you are not responsible for the good time of others, have the time to lean the lay of the land and can enjoy the beauty for yourself. In the BVI everything is easy. Rarely true of everywhere else I have chartered.