Spelljammer Converting Spelljammer creatures

[Cleon]

Sure, I like that, and it's reasonable (both from the size in general and in-game using hexes).

Since two out of the three of us are agreed on that I'll update the Gammaroid Working Draft.

Oh dang, my previous post should be "13 hex diameter", not radius. I'd better correct it.

 

[Cleon]

I guess that puts the Ramming attack next on the list.

I have some ideas for that, but it'll have to wait a few hours since I've got things to do.

 

[freyar]

Very good, then, carry on.

 

[Cleon]

Very good, then, carry on.

Thank you my good sir.

The Gammaroid Original Stats have this for the Ramming:

When this deadly missile hits a ship, the target suffers an automatic “Ship shaken” critical hit; the whirling serrated edge of the gammaroid’s shell may (30% chance) cut in half or utterly destroy the ship. In atmosphere, atmospheric friction from its rapid rotation creates an enveloping fireball that causes an additional 12d6 damage. The gammaroid uses this whirling attack primarily against its favorite prey, the gossamer noble (q.v.).

Unfortunately, it doesn't list any actual damage apart from the additional fire damage, the original ramming does a critical effect plus a 30% chance of destroying the ship. I'd think it should do at least as much as its full attack damage.

Anyhow, here's a first draft based on the Chont's version of Ramming:

Ramming (Ex): As a standard action, a gammaroid that is using Spinning Flight (see below) can fly at up to triple speed (1,350 feet) and ram an airborne target such as a spelljamming ship or flying creature. To ram, the gammaroid must end its movement in the target's space. This attack deals ??? points of damage, plus an additional 12d6 fire if the gammaroid is employing its Flame Sheathe ability (see above). If the target is a creature, it can attempt either an attack of opportunity or a DC 92 Reflex save for half damage. The save DC is Strength-based.

If a gammaroid rams a ship, in addition to the above damage it also makes a Strength check to breach its hull. The break DC varies with the type of vessel rammed, with typical values as follows: rowboat DC 20, keelboat DC 23, sailing ship or longship DC 25, warship DC 27, or galley DC 30 (See Chapter 5 of the DMG for information about ships). Success normally holes the hull, causing the ship to founder in 1d10 minutes. Success by 15 [?] or more (e.g. a result of 40+ against a break DC 25 longship) immediately destroys the ship by shearing the hull in half or smashing it to splinters.

Regardless of the check result, every creature aboard a ship rammed by a gammaroid must attempt a DC 15 [?] Reflex saving throw. Success means the creature takes 1d6 points of damage from being thrown about by the impact; failure means the creature is hurled overboard.

 

[freyar]

This is generally fine. But I do wonder if a Large or smaller critter should perhaps get a Ref save to avoid being rammed since they're small enough just to duck a bit out of the way.

 

[Cleon]

This is generally fine. But I do wonder if a Large or smaller critter should perhaps get a Ref save to avoid being rammed since they're small enough just to duck a bit out of the way.

The thing's hundreds of feet wide. That'd make it a bit hard to sidestep out of its way.

I'm also thinking we should increase the "shaken damage" the crew takes, considering the high speed and enormous mass involved.

 

[Arnwyn]

Yeah, I would say a ship getting smashed by something so big would toss people around pretty good - more than 1d6...

 

[freyar]

The thing's hundreds of feet wide. That'd make it a bit hard to sidestep out of its way.

There are also likely lots of indentations in the shell, assuming it has to end its movement when it first enters your space.

Then again, maybe we should allow it to plow through objects smaller than a certain size, knocking them out of the way (and damaging them of course).

 

[Cleon]

Yeah, I would say a ship getting smashed by something so big would toss people around pretty good - more than 1d6...

I did some sums, and in real world terms the impact would be devastating.

It's speed of 1,350 feet in a round is 810,000 feet per hour, or roughly 153.4 miles per hour. That's 65.58 metres per second if you prefer SI units.

That speed's in the same ballpark as the launch velocity of a long-range bow or siege engine, so we're talking of an impact similar to being hit by a catapult stone that weighs four million tons and is on fire.

Kinetic energy is ½ × mass × velocity². With a weight of 4 million short tons that gives KE = ½ × 3,628,738,960 kg × 68.58² metres a second = 4.27 Terajoules.

4,270,000,000,000 joules is scary.

A normal longbow arrow is about 100 J, give or take.

An AP shell from a 16-inch Navy cannon has about 350 Megajoules when leaving the muzzle. You'd need about twelve thousand such shells to match the gammaroid's 8.53 TJ.

For another Naval comparison, a Nimitz-class aircraft carrier would have to be travelling at almost the speed of sound (about 633-648 mph or Mach 0.83-0.85) to have that much KE.

However, the gammaroid is so massive compared to most ships and creatures it wouldn't transfer much of that energy to them in an impact - a medium-sized creature would just splat up against it like a fly hitting a speeding sports car.

Its speed's the same as the impact velocity of a fall from approximately 787 feet under standard gravity (9.80665 m/s², or ~32.174 fps²), so relatively speaking it'd be similar to falling onto a mountaintop from that height. Unless it's using Flame Sheath, in which case it'd be like falling onto an erupting volcano.

[1,350 feet per round is 225 fps. Divide by g of 32.174 fps² and you get 6.99 s, so it's the distance fallen in about 7 seconds at that acceleration. Acceleration distance from a stationary point equals ½ × acceleration × time², or ½ × 32.174 × 6.99² = 786.7 feet]

 

[Cleon]

There are also likely lots of indentations in the shell, assuming it has to end its movement when it first enters your space.

Yes, the bit about stopping on impact was just a carry-over from the Chont special attack. The Gammaroid makes no mention of it stopping on impact, and something with that much momentum would need to hit something the size of a hill to stop it.

Then again, maybe we should allow it to plow through objects smaller than a certain size, knocking them out of the way (and damaging them of course).

I'm sure we had a variant on the Trample special attack that worked like that - moves through smaller opponents but stops on hitting a bigger opponent...

Hmm, I thought it was the Stargazer's "Rolling Trample", but that doesn't seem to be it. Oh well, I might find it later.