Jonathan_S wrote:And then normal ships their wedge massively shrinks the angles that hostile fire can hit you from -- the provided info lets us calculate that looking out the broadside of an SD a PDLC only has to worry about a 31.2 degree vertical slice of sky (+/- 15.6 degrees if it was mounted halfway up the broadside) at the extreme aft of the wedge, and a 106 degree vertical slice of sky at the extreme fore of the wedge. But most weapons fire would be coming in closer to perpendicular, rather than slanting in from just off the kilt or throat of the wedge to hit the broadside -- so the more likely angles are between a 64 and 75 degree vertical slice.
Anything above or below that is obscured by the outer lip of the wedge.
No ship handler worth his paycheck would angle the throat or kilt to the oncoming attack. They'd turn so the wedge faces the attack (GA ships) or the sidewalls do (everyone else). There's probably a sweet spot angle of how much sidewall and how much wedge to have that allows firing CMs and PDLCs, but also protects the most.
Missiles can't all be travelling on the same plane so there's even less danger than the numbers above would indicate: some of the missiles have to be above or below the lip of the wedge when they reach stand-off range. None of that applies to a wedgeless ship.
But a triple-skeg spider ship doesn't have that - a PDLC on one of its three broadsides has to worry about the entire 120 degree vertical slice of sky (less whatever small amount might be blocked by the skeg towering overhead at the edges of that). Plus of course no angle has the immunity to fire that the wedge gives from shots coming above or below it.
Right, there's one big advantage with the triple skeg: you have three broadsides instead of just two to mount point defence weapons on. If each one has 120° of coverage, then they together cover everything; if they have more than 120°, then there's redundancy. And if the ship angles itself so a skeg points to the oncoming attack, then two broadsides are at play.
The problem is this big advantage does not offset the big
disadvantage of having to cover 360° around the ship in the first place. It doesn't come even close!
Given that the triple broadside they 3 skegs require has pros and cons; the downside is you need to spend mass, volume, and industrial output to build and install weapons on all three, so basically wrapping all the way around the 'barrel' of the hull - where-as impeller powered ships can concentrate their weapons onto their two smaller broadsides and leave the dorsal and ventral surface free for boat bays, sensors, thermal radiators, etc. The spider ship has no equivalent free area and will need to intersperse those with the rest of the things competing for space in its broadside. On the pro side, given that it has no wedge to protect the top and bottom, it's a good thing that the triple broadsides let it have defenses pointing in all directions -- it'd be in real trouble if it had a non-wedge engine that still prevented you from sticking defenses on the top and bottom.
Another downside is that since and spot around the barrel of the hull is equally likely to be pointed towards the enemy and be hit the full thickness of hull armor needs to wrap around the entire hull -- again a wedge lets you economize on armor (cost, volume, tonnage) on the top and bottom -- with smaller ship dispensing with it entirely and trusting to luck not to have a shot graze over the hammerhead and glance into the unarmored dorsal or ventral hull; and wallers reducing the thickness of armor up/down there.
Another one is due to the tactic that those ships are likely to employ: stealth. Any hit, even if not anywhere close to crippling, would compromise the stealth of the ship. If the opponent hadn't locked on the ship before, they will now. So an LD cannot afford to take
any hits, unless it's suiciding or about to translate to hyper anyway. Even if it does withdraw, its follow-up missions may need to be scrapped because it can't insert into the target system and sneak up, until it gets sufficient repair.
All this points out that there just has to be something more about those ships, because they're too fragile.
Another pro is that without the wedge you don't get the more limited sensor readings looking up or down like regular warships do when looking through their wedge.
That's a very minor saving grace, given that everyone has recon drones.
Finally, I'm not sure if we're explicitly told that the Lenny Dets will also be triple-skeg designs. We know that 3 is the minimum number, but I guess on something that big they might go for a 4-skeg design; so they get a broadside facing each cardinal direction, (so only having to cover 90 degrees of 'vertical' firing arc, rather that 120)
I think they do. Wasn't Albrecht Detweiler looking at them while in construction when he mused about their atypical design? Or was he looking at the Sharks and Ghosts? Either way, given that the Sharks were the scale prototype for the LD, one would assume that both share the same form.
If I had the ability to go for more than 3, I'd go for an hexagonal cross-section instead. That gives you a higher surface-to-volume ratio. But that may not be possible because the skegs themselves need to protrude from the rest of the hull.
