There is a lot of advice here and it is very confusing at this point and I'm certain the OP is scratching his head
to determine whether to use a staysail or not.
There are so many variables in rigs and they are set up to the designer's purpose on any given boat. To say lowers are not necessary will not apply to every boat design. So I suggest the OP find out if he has a sloop
etc. and start there. I have a high aspect ratio cutter
rigged sloop for instance. It has two shrouds in line with the mast port and starboard. One goes to the top of the mast, and the second goes to the upper spreader attachment point on the mast. I have a forward lower and an aft lowers that attach to the mast at the lower spreaders. All of these hold the mast in column. The baby stay as I call it, others will call it the forestay, or staysail stay, is attached to the mast at the upper spreader and runs to the foredeck parallel to the jib stay. I have running backstays
lead from the upper spreaders to a turning block attached to a pad eye in the stern of the boat deck. These are controlled by the spinnaker winches. The weather
side running back is always tensioned when flying the stay sail. Even with my forward and aft lowers, the mast pumps without the running backstays
. Now to top all of that off, I have a hydraulic backstay used to improve jib stay tension. All of this was designed and built by Ted Hood
. The operative words in my rig are high aspect ratio
which Mr. Hood
explained to me is why it is considered a performance cruiser.
I went thru all that so that the forum needs to be more specific about the rig design they are comparing to when saying you don't need a baby stay, only a wire rope
luff sail, or you don't need running back stays, or just use your spinnaker halyard fore a baby stay. In optimal conditions, all that might work fine until less than optimal conditions come into play. A broken mast at sea is a dangerous thing to deal with when the wind
and seas are acting up.
If the C & C 30 is truly a cutter rig sloop, then I would use the staysail when close reaching and beating to the wind
. You will get more power and be able to carry less or reefed headsail in higher wind velocities. You can roll up the headsail and use the staysail in stormy conditions with a reefed main as I have done often. And finally, you are more likely to be hove to better with the staysail and reefed main.
I didn't discuss fractional rigs because if you tried a staysail on that design, it would be a real homemade system. I highly recommend working with the design intended by the manufacturer and get a good sail loft to help with the combinations you will need.