I'm sure it would work to some degree but the sail area would be a long way forward and probably very high. A removable inner forestay or a cutter rig has the advantage that the storm jib is set closer to the mast and much closer to the deck.
It would also need to be flat enough to enable you to make some headway close hauled (eg off a lee shore). Most genoas would be cut too full and may not be made of heavy enough cloth in any case. The cost of cutting down a genoa properly is unlikely to be much less than obtaining a storm job from SeaTeach or a similar cut-price sail source.
1 Centre of effort will be too high with a heavily furled genoa. You need the storm jib quite low or the heeliing moment will hav you over on your ears.
2 You'll not be able to point at all. All of that furled said will stall the airflow. If you get stcuk and need to work to windward - you'll be knackered.
If you are planning to deal with heavy weather - get the right kit.
Two good points, though I would have thought that a tight, partially furled genoa (as it would be in strong winds) wouldn’t disrupt the airflow any more than one of these pseudo storm jibs that wrap around a foresail.
I envisaged the problem would be the extra strain on the furling gear, if it becomes unfurled you are well stuffed. And that the jib is set too far forward.
re "You need the storm jib quite low or the heeliing moment will hav you over on your ears."
I had always thought that a higher storm jib was better (and thats why it tends to have a strop) cos it then would'nt catch loads of water in rough seas and also help visibility
I have a storm jib, and frankly never have used it - preferring to use a yankee 85% on the roller reefer. I've been out in 50 knots and that was plenty large enough rolled down to about 1/2 the size of the storm jub.
My boat at the time was a Hallberg Rassy 42. I was on a broad reach before about 45kts. With the furled genoa, not more than a dish cloth out, I was all over the place and feeling quite insecure. As soon as I set the "hard wind sail" on the inner forestay, calmness and serenity reigned. It was a sail whose foot was at deck level and it was serene. Carried the rig for nearly two days.
The wind backed and she was now running and more sail was required to keep way on in a lumpy sea. So I stowed the storm jib and re set the furler.
Approaching land I concluded (far too late) I was in the wrong place and needed to make something to windward. There was no way that my reefed genoa and three reefs in the main were going to do that. She stalled, paid off became pressed and then repeated the whole shebang once we headed up.
Set the "hard wind sail" and we were off to the races.
I am getting more and more confused as I explore storm jibs. I have a cutter rig with furlers on both Genny and jib. I can't easily fit a secondary forestay - apart from the expense. What are people's views on the Saturn storm jib reviewed recently in Sailing Today? It is the shape of two sails joined at the luff and wraps around the furler. Review was good....