Flotation isn't necessarily the answer ...
For many of the older pocket cruisers, it just isn't practical to attempt to stuff flotation in the seemingly "unused" areas. It simply isn't feasible to make up the weight of a lead or steel ballasted keel. The spaces you may think of as "unused" are actually necessary for access to boat systems in most cases. I couldn't (or wouldn't) stuff foam in any area where I need to gain access. Under gunwales, I need access to stanchion fittings, underside of winches, runs that include electrical or controls for the engine panel, for instance. Under the cockpit, I need access to the fuel tank, the engine, exhaust, mufflers, the drive shaft, shaft log, steering components such as cable, wheels and all components associated with the rudder. Aft of the lazerette, I need access to the cockpit drains, water heater, water pump, fuel fill, etc. So that pretty much eliminates all of the seemingly "unused space" aft of the cabin.
Within the cabin, under the settees, I need space for water tanks and plumbing. Behind the seat cushions is the hull. Just under the deck, access for wiring & the stanchion fittings. Going forward, I need space for the toilet plumbing and the holding tank, and more fresh water for the toilet (if I want it). Forward of that is the anchor locker.
So where is this flotation supposed to go? It's easy to see how older pocket cruisers just don't have the space. Of course, they don't seem to make new pocket cruisers in the sizes from about 24' to 28' like they used to. The newer boats in that size seem to be oriented to much lighter displacement and daysailing or racing use (not cruising for sure) so it makes sense to add flotation where the space isn't monopolized by "systems". But I hardly see any call for legislating this requirement as you previously mentioned. Why should government stick their nose where it is not necessary. Why should there be legislation that forces all designs into a shoe box? I say let designers and markets dictate where the boat designs go.
From a safety standpoint, I think it unnecessary. The keel performs the self-righting function, not a foam filled mast. I want my halyards in the mast, not foam. Good seamanship dictates keeping your hatchboards locked in place and reefing or dropping sails when conditions go south, as precaution in the event of a knockdown. Thus self-righting should be assured without need for flotation. But I'll acknowledge that sad events can't always be avoided and I don't mean to point a finger at anybody who suffers losses.
In the case of the Cal 24 that sunk, I haven't heard the circumstances. But with all the talk about how shallow the bay is, it is hard to imagine that the boat turned turtle, unless they happened to be in a deep water area. It's not hard to imagine that the mast may have been driven into the mud, though, in which case, flotation may not have been any help.
For many of the older pocket cruisers, it just isn't practical to attempt to stuff flotation in the seemingly "unused" areas. It simply isn't feasible to make up the weight of a lead or steel ballasted keel. The spaces you may think of as "unused" are actually necessary for access to boat systems in most cases. I couldn't (or wouldn't) stuff foam in any area where I need to gain access. Under gunwales, I need access to stanchion fittings, underside of winches, runs that include electrical or controls for the engine panel, for instance. Under the cockpit, I need access to the fuel tank, the engine, exhaust, mufflers, the drive shaft, shaft log, steering components such as cable, wheels and all components associated with the rudder. Aft of the lazerette, I need access to the cockpit drains, water heater, water pump, fuel fill, etc. So that pretty much eliminates all of the seemingly "unused space" aft of the cabin.
Within the cabin, under the settees, I need space for water tanks and plumbing. Behind the seat cushions is the hull. Just under the deck, access for wiring & the stanchion fittings. Going forward, I need space for the toilet plumbing and the holding tank, and more fresh water for the toilet (if I want it). Forward of that is the anchor locker.
So where is this flotation supposed to go? It's easy to see how older pocket cruisers just don't have the space. Of course, they don't seem to make new pocket cruisers in the sizes from about 24' to 28' like they used to. The newer boats in that size seem to be oriented to much lighter displacement and daysailing or racing use (not cruising for sure) so it makes sense to add flotation where the space isn't monopolized by "systems". But I hardly see any call for legislating this requirement as you previously mentioned. Why should government stick their nose where it is not necessary. Why should there be legislation that forces all designs into a shoe box? I say let designers and markets dictate where the boat designs go.
From a safety standpoint, I think it unnecessary. The keel performs the self-righting function, not a foam filled mast. I want my halyards in the mast, not foam. Good seamanship dictates keeping your hatchboards locked in place and reefing or dropping sails when conditions go south, as precaution in the event of a knockdown. Thus self-righting should be assured without need for flotation. But I'll acknowledge that sad events can't always be avoided and I don't mean to point a finger at anybody who suffers losses.
In the case of the Cal 24 that sunk, I haven't heard the circumstances. But with all the talk about how shallow the bay is, it is hard to imagine that the boat turned turtle, unless they happened to be in a deep water area. It's not hard to imagine that the mast may have been driven into the mud, though, in which case, flotation may not have been any help.