Batlling sea monsters

[BzAli]

I'm GM'ing a party of 4 players, level 8. They have a pretty well equipped ship, with a broadside of 10 ballistas and a gunnery crew lead by a cohort with all necessary siege weaponry feats to make them work.

I'm thinking of throwing some sea monsters at them. I think I can improvise some rules treating the monster as an enemy ship and thus allowing some sort of ship vs. monster combat. But what kind of CR am I looking at? How do the ship and it's weaponry factor into the strength of the party? Would a CR 9 or CR 10 monster be to tough on them?

My players are pretty experienced, and have built dangerous characters. So I shouldn't have to pull punches. :)

[Herbatnik]

Try to use smart monster ( or beast leading by smart character , ex huge whale commanded by druid sahuagin), which will attack PC ship underwater, without fear of ballistas and catapults. This will force players to go underwater, since damaging hull for 30-40 damage sink their ship in few minutes.
Also, dragon turtle is nice one- being partial underwater give +4 ac and dragon breath underwater generate steam which obstacle visibility to artillery. And last but not least- ability to capsize the ship. Hard to obtain, but can be fun and generate interesting challenge- reverse ship to normal position.

[vikingson]

Seamonsters use the ocean as a 3D battlefield. Surges from below (int the ships hull) should usually come as a surprise - unless the players have some sort of sonar - limiting the actions to be takn. Also attacks shoul not usually ome happily stupid from the sides of the ship (so a broadside can be fired), but quie posibly from the ship's wake, as the monster trails the ship.

Shoing theough your capatains cabin : not advised. Hurling stones though your own rigging : inadvisable as well. Catapults mostly if ever workrd well on galleys. And indirt fire-weapons like Mortars were mounted on specialized ships without a foremast which might get in the way...

Also take into account the reason for the monster attacking : snatch, and grabbing some on-the-swim food ( picked up from the quarterdeck), fending off the Intruder to their haunts (say ships and dragon turtles) which might lead to prolonged battles until one or the other is destroyed/crippled etc. Have seaserpents and other predators with breath weapons stay submerged until these are ready, then blast the ships (the heroes might survive, the guncrews... unlikely ). Do they tcually want the treasure aboard (easier to snath underwater anyway) or a sort of come as-you-are buffet ?

If they are smart, they might snatch at (and bite through) the rigging, then dive again. Enough bites = crippled ship. Or pick off the steering crew which is likely to be exposed on the quarterdeck...

besides : monsters charging a ship might well do so just under the surface (looking at Pacific Rim and Gozilla for imagery), gaining nice cover from the waves running over them and enever forget - a ship reaches well down into the water, to a depth of 15'-to 20' trying to stove in or overturn the vessel ? Congratulations - you now have a door sized leak in the side of your vessel... flooding ! Makes you wonder whether the crew will stay at their weapons or make for the lifeboats. Or stay in the shaking and slowly leaning masttops

Kraken etc might attack to grab from below an are smart enough to hang to only one side of the vessel and dive quickly (capsizing it). Once the ballast drops (at an angle of more than 80° - yes, the ballast is fairly loose, for trimming purposes ) , there will hardly ever be a good chance to right the vessel ever again, especially since now water is rushing in through the gunwhales, scuppers and open hatches

And as even a lot of fish are smart enough to simply bite off the fins of an enemy fish....why not have them bite/rip off parts of the ruder, making the vessel unmanoueverable ? Or chop through the anchoring hawser and wait until the clueless/crewless vessel finds itself as easy picking on a reef/sandbank

Perhaps also start out smaller with monsters attacking the lifeboats, then upgrade from there ?

Enough nasty ideas ?

[BzAli]

Excellent. Thanks.

[vikingson]

reminder to self... never type anything lengthy on your pad^^

Last thought though : have the battle commence at night !

Any ship in tropical waters will be nicely outlined by phosporecent foam in and of the wake, while the monster at best will be a dark shadow somewhere out there. Not sure whether Darkvision breaks through the surfac of the ocean (it does not for us), so spotting and boradising stuff, in the darkness... will take som planning (such as an illuminated barbed harpoon ). even then Monsters will benefit from concealment and potentially cover (under the surface).

Darkness is the enemy - or in the words from a friends campaign

Lookout : "breakers breakers I am spotting breakers"
XO (panicky) "Where ?"
Lookout : "underneath the bow !!!"

if it works for reefs, it sould work for sea serpents as well^^

[FrankManic]

Territoriality is another good factor for justifying monster attacks. Unintelligent monsters could view the ship as an intruder in their territory.

I've come up with the idea that in a world where sea monsters are very real every ship has a couple of water breathing crew who can provide some kind of early warning, at the very least. Even if it's just one half-sea-elf or a barbarian who is really good at holding his breath they'd need someone who can take a look under the water to make sure they don't have a pack of Tojindas swimming silently in their wake forty feet down.

Eitherway - I did a giant squid attack on the Wormwood as a way of demonstrating how dangerous Harrigan is. I ran it as a bunch of tentacles, each treated as an individual creature, flailing around trying to grab people off the deck to eat them. The body of the creature was directly under the ship while the tentacles came up on both sides to create the classic image of the Kraken dragging down the stricken ship. The PCs fought off a few tentacles until Harrigan went underwater and just gutted the thing.

I'd suggest watching 20,000 Leagues Under The Sea for a great depiction of a "sea monster" attacking a tall ship. The Nautilus attacks ships by getting up to speed and ripping through the target ship's keel using a large ram prow. A monstrous dire shark could do something similar - Have horny growths or bone ridges on it's back that it uses to rip out the bottom of a ship.

Intelligent critters could also attack the rudder to disable the ship. Something smart like a Kraken could get something sharp and actually drill through the bottom of the ship, or use magic to shatter the hull from a safe distance.

And for a twist you could have sea monsters that aren't actually hostile, but are simply approaching the ship out of curiosity. Of course curious large predators tend to explore new things with their teeth...

[Fitzwalrus]

FrankManic wrote:

I did a giant squid attack on the Wormwood as a way of demonstrating how dangerous Harrigan is. I ran it as a bunch of tentacles, each treated as an individual creature, flailing around trying to grab people off the deck to eat them. The body of the creature was directly under the ship while the tentacles came up on both sides to create the classic image of the Kraken dragging down the stricken ship. The PCs fought off a few tentacles until Harrigan went underwater and just gutted the thing.

Oh, I reallylike that idea.... a classic sea encounter and a chance to ram home "don't mess with Harrigan".

Yoinked, and thanks!