[Low-Tech] Landing Craft at TL2 to TL4
 

In a world very different from our own, with supernatural powers, widespread magic, supers on every side in warfare and so on, warfare follows a very different path. Hence, warfare in Dungeon Fantasy or, indeed, any Fantasy world with reliable and reproducable supernatural phenomena useful in warfare never develops along lines familiar to our non-magical Earth.

One thing that is prominent is the heavy emphasis on special operations*, with espionage, covert operations and surgical behind-enemy-lines strikes against the sources of their magical powers often deciding the outcome of battles.

In my TL 1+2, TL1+3, TL 2+1, TL 2+2, TL 3+1, TL 3+2, and TL4 campaign, the PCs are prosecuting a war where control of the oceans and the immense logistical advantage conferred by maritime resupply is key to the strategy of both sides. Accordingly, they want to move past merely raiding the enemy ports to destroy shipping and actually capture the ports that the other side is using to supply their three great field armies that are moving against the last bastions of the side that the PCs are supporting. Thus, hopefully, stranding tens of thousands of enemy soldiers in a hostile land without adequate resupply.

At real world TL 4-5, ships' boats were quite sufficient for amphibious operations. The PCs have the equivalent of TL 4 ships, with a few early TL 5 ships, so they have longboats, cutters and captains' gigs aplenty, manned with doughty Jack Tars and marines armed with smokepowder weapons.

They've had some two months to construct more boats to aid in their amphibious operations, however, and it would probably be effective to construct boats longer and heavier than those routinely carried on sailing ships. They only need to sail a distance of 25 miles, after all, and can be dragged behind sailing ships or galleys if needed.

I was wondering what might be reasonable designs for landing crafts for the proposed amphibious attacks on the two port cities. I considered some designs more efficient** than ships' cutters or longboats, such as chalanas, barges, chasse-marées, feluccas, war canoes or catamarans.

Various local people are partial to galleys, feluccas and catamarans.***

What would be a reasonable design for the PCs to order for their amphibious assaults? What would be the GURPS stats for something that was bigger than a ships' boat, but smaller than an average Age of Sail ship, which could be used as a landing craft in TL4 warfare?

*I. e. stuff PCs do in Mass Combat situations.
**In terms of both man-hours needed to construct it and crew needed to work it, compared to the amount of men and materiel that it could land in a given period of time.
***Local pirates who build extremely fast sailing and rowing boats of that design, with whom the PCs recently allied.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

Unless you need to roll vehicles off the ship, any boat capable of landing will do the job. Unless you need greater speed and/or stealth, barges are the easiest.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

Most ships, certainly most purpose built warships were capable of being beached. Perhaps not a giant roman bread vessel, or one of those monster warships of the Macedonian Succession Wars that they were so ridiculously fascinated with and did little good to anyone but Archeologists. But a typical Venetian galley or Norse longship, or a Macdonald Berlinn(Scotch galley) could do so and would routinely on various missions. No Ancient or Medieval power needed specialized landing craft as such very much.

What was needed was something that could carry the horses and heavy impedimenta of a first class army. But back country polities like the Norse and the Macdonalds wouldn't have such amenities, and powers like Venice that were chiefly maritime would place lower priority on them.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

I seem to recall several accounts of crusaders using ships fitted with ramps via which horsemen could ride directly onto the shore - probably the medieval version of an LST.

In the C19, I also seem to recall accounts of shallow draft, square bowed boats being used to land troops - probably modified lighters and mainly used to land horses, guns and/or stores as troops can be landed in regular boats.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

Here's an interesting horse transport from the Gallipoli operation, might be inspirational: http://en.wikipedia.org/wiki/File:V_..._Gallipoli.jpg

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

They had such things on the Med and plenty of experience transporting horses but neither were as common in the Atlantic. David Howarth believed that if Harold Godwinsson had returned Williams army would have been immobilized by seasick horses. Seasick men too but that is another story.

Unless there was a prolonged inland campaign in mind most amphibious operations had no cavalry involved. A simple island-snatch would have been an infantry op. Even the Great Heathen Army stole most of it's horses from the Saxons on arrival rather then bringing them along.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

Here is the key to your answer...
Build as many of whatever type the construction crews are already familiar with and have timbers seasoning for. Don't try changing the design with a 60 day build window.
If it is only towed barges then so be it, but if you try to get fancy and introduce the 'newest greatest thing' as a last ditch defense against an invader who has got you on the ropes you are taking unnecessary risks, not least of which is construction delays while they figure out that bit that doesn't QUITE work.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

This is true. On the other hand, the PCs need the capability to quickly land more troops than will fit into their existing ships' boats. Hence, the need for building more. And as these are being built for a single purpose, i.e. amphibious landing, it makes sense to adopt a design optimised for that role and not, for example, a design that needs to be small and light enough for it to be hauled in by larger ships.

Both speed and stealth are extremely desirable, as the PCs must figure on the possibility that deception and covert strikes by supernatural special forces will not be enough to prevent the opposition from defending their fortified docks with priests, mages, archers, slingers and mechanical artillery launching magical projectiles.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

OK, things are becoming a bit clearer now, but there's an open question. Are these craft specialised for landing troops in a port, or on a beach? Or do they need to be able to do both? The latter makes it harder.

For landing on a beach, you want something like a Thames sailing barge. At 25x6 metres, they should be able to carry at least 200 men for several hours, and they're reasonably easy to beach and refloat, providedyou know how the tide behaves off the enemy coast. The TL4 version may not have the leeboard (retractable keel) which will limit their ability to sail fast, and against the wind. If this seems too advanced, something based on a Norfolk wherry will certainly be possible - they existed at the historical TL4.

Note that while these craft will do fine for narrow seas - the English Chanel and North Sea were their habitats - sailing them across large oceans in bad weather is not a good idea. I presume this is happening in summer, before the summer storm season? When dealing with sailing ships, weather is always the primary unpredictable factor. Do the PCs have weather magic? If so, they need to be planning around that.

If you want to sail into a port and capture it, the requirements on the ship are less severe, provided you know how deep the port is and what the tides are doing. You can use larger ships with proper keels, which are much safer in bad weather. You need to provide some defence for the troops on deck, and you need to be able to land them rapidly, and you can combine these requirements by mounting timber movable bridges along the sides of your ships, using them for the troops to hide behind on the way in, and then swinging them out to the shore or wharf for the troops to run down. Of course, you need to know what wharfs are where and how high they are: there are reasons why professional navies collect this kind of information.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

The PCs are from another realm, far to the west over the local analogue of the Mediterranean, and arrived with a flotilla of ships. They have complete command of the ocean between their homeland and the realm being invaded. They also have significant mercantile contacts in some five or six large cities along the sailing route from their homeland to where the war is.

The invaders no longer have the country for which the PCs are fighting on the ropes, really. They still control 80% of the land area of the country they are trying to take over, but their logistics are falling to pieces, their fleets have gone down in sea battle after sea battle and one of their three field armies just suffered a catastrophic and shattering defeat after the dragonic vassals of a neighbouring power entered the war on the side of the PCs.*

If the PCs manage to take the two cities they propose to seize by seaborne assault, then the majority of the invading troops will be trapped without any way of resupply from the mother country except by a torturous overland route. Which effectively means that they will be unable to hold any part of the country north of those ports they still control. And they'll probably lose thousands, if not tens of thousands, during the retreat.

If the PCs fail to take these cities, it means that the war stalls for both sides. Unless the invaders can win some sea battles in the near future, however, they are not likely to make any more advances and are, in fact, likely to lose some of the territory they now hold, even if the amphibious landings fail.

The sixty day window is because the PCs are impatient to deliver a knock-out blow to the northern armies of the invaders. They want to claim credit for victories even more glittering than that recently achieved by the Wyrm Princess Shudu-Ab, Breath of the Red Ravager, High Priestess of Tiamat, and her dragonic allies.

The PCs could have bought boats abroad and transported them to the theatre of war, but for security reasons, they prefer to have local tribes prone to pirantical ventures construct them on an island where pirates congregate. They'll be used to building small, swift galleys used to raid coastal settlements and the local pirate specialty, a catamaran raiding galley design.

An ideal vessel would be capable of moving something like 50-70 men fairly swiftly, using perhaps 30 rowers, for a total capacity of 80-100 men. Move 3 would be very desirable, with higher Move even better.

*Well, their own side, really, but at the moment, they and the PCs have a joint interest in defeating the invaders before they come to blows over power in whatever post-war polity succeeds the ineffectual and anarchic patchwork of resistance figures.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

They are meant to take ports, but will assume that the enemy will make it extremely hard to land troops on the wharves themselves.

The plan calls for landing troops on a nearby beach, bombarding the barracks from the air by magical means, dispatching summoned aquatic monsters and swimming polymorphed commandos to clear port defences and finally sending in several 'forlorn hopes' of boat-borne assault troops to seize the various floating docks, wharfs and natural landings along the river that runs through the port city.

Lightly equipped volunteers led by PC superheroes and magically-aided commandos will storm the walls of the city from the inside, after landing on the docks. Then they propose to seize a gatehouse and let the troops that landed outside the city in.

Both look very nice for their purposes. They'd need faster assault craft to complement them, for the first wave of attackers, but these would do very nicely for landing the main force on a beach and along the river.

It's spring, in seas fairly equivalent to the Meditarreanean around Alexandria, Egypt.

Both sides have weather magic. There are reasons to assume that the seas will be fairly rough, but there won't actually be a storm.

The PCs already have some forty warlike sailing ships and around a dozen galleys that could enter a port which they have already seized. Add to that some twenty cargo ships for logistical purposes.

But until the most powerful mechanical artillery pieces are seized or destroyed, it is extremely risky to sail such ships into the narrow confines of a port. Not to mention that aquatic monsters or swimming magic-users could sink them easily.

So the most valuable ships will not enter the harbour until volunteer assault troops in less valuable landing craft have cleared the way and stopped artillery from sinking them.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

The PCs are using frigates, brigs and 'war caravels' that are TL3+1 or TL4+1 sailing ships. Their allies have TL2+1 galleys and liburnians, as well as TL2+2 catamaran raiding galleys.

The PCs have two large horse transports that are converted medievalish galleys and two more should be ready when the attack is launched.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

Four older war galleys that were captured by men under the PCs have already been converted to hippogogi/taridae, i.e. horse transports that can carry some 25-30 horses each, along with riders and war harness.

They'll be used in the assault againt the larger city, landing a cavalry force of around 100 men on a beach outside the city, meant to screen the advance of the army that lands outside.

They'll probably be packed with men as well, as many as can fit on them, as they'll only be sailing a distance of 25 miles to make the landing.

Yes, but what are reasonable GURPS stats for such larger versions of ships' boats like longboats and cutters?

I'm principally interested in what kind of Move one can expect, with maybe 12 rowers for the smaller versions, up to 30 for the largests.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

Some of the best landing craft look to be captured galleys and the light coastal raiding vessels of local pirates, largely because they are already purpose-designed for landing warriors to loot and pillage.

However, the PCs most likely do not have enough of those to land all the thousands of troops that they need.

Assuming that you can get several carpenters and an infinite supply of semi-skilled labour to work on each craft, what is a reasonable vessel to build in 60 days?

How long does it take to build a TL2 galley like the bireme or any other type that's fairly simple to build (i. e. not the huge polyremes)?

What about the earlier heroic Greek penteconters, which are essentially just long open-decked boats?

Or a typical Age of Sail ship's boat, like the cutter or longboat?

And how much does it change stats to make the galley or boat wider, enough so it could hold maybe as many passengers as rowers?

That would obviously slow them enough to make them useless in ship to ship combat, but these are landing craft, not fighting ships.

How many passengers could one transport with 30 rowers while still attaining Move 3? What kind of vessel would you use?

If I want to transport ca 5,000 soldiers and not need more than 2,000 rowers and sailors*, but I want Move 3+ for at least a thousand of them and at least decent pace of landing for the rest, what size of boats, open-decked galleys or barges do I want?

*For the actual landings. The rest of some 10,000 sailors and about a hundred ships will be busy with the logistics that allow the landing and keeping enemy ships away by controlling the seas.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

There doesn't seem to be much written up on shipbuilding for 4e. The nearest thing I can find is this sidebar in High-Tech for 3e:
Under 4e, Shipbuilding is replaced by Engineer (Ships), and Blacksmith with Smith (Iron).

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

You might be able to use Ghostdancer's Sailing the Open Skies article (Pyramid #3/64) here. Briefly, a vessel can have up to 3 oar systems, with one giving it Move 1/3 and each additional increasing maximum speed by +1. An SM +5 (30 ton) ship needs 4 rowers per system, SM+6 (100 ton) needs 12 per system, and SM+7 (300 ton, the largest that can use oars) needs 40 per system. The article suggests, in a cinematic campaign, allowing strong characters to count as more than one rower - each doubling of BL from 20 counts as an additional rower (EDIT: If you want to allow characters to have a fractional effect, log base 2 of BL/10 will give you your multiplier. An ST 12 character thus counts as 1.5 rowers. Note this will mean characters with ST 7 or lower can't contribute).

In a highly cinematic setting, or one where humans can be superhuman thanks to magic, it might be appropriate to allow very strong rowers to function as though the ship had more systems than it does. That is, if you have a 30 ton ship with 4 ST 20 rowers, each of those rowers is functionally equal to 3 normal rowers (they double BL 20 twice), so the ship has Move 1/5 as though it had three systems. If the above ship did have three systems, and each of the 12 rowers had ST 20, they'd count as 36 rowers. That's 9 systems, for something like Move 1/11.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

I hadn't noticed that an article about airships had Oars as a system for the Spaceship design system. Neat.

I can't help but notice how excessively favourable it seems, compared to real life, though.

First of all, why would there be 144+ rowers on historical rowing ships, going up to 420 rowers or so for the biggest galleys that can't be explained as hyperbole in ancient sources, if 120 rowers could attain the maximum speed for a ship up to 300 tons in weight?

And why would the sole historical war galley design to demonstratably attain Move 5 use significantly more than 120 rowers (170) and weigh less than a third of 300 tons (less than 80 tons fully loaded)?

Also, what prevents a SM +8 ships from having oars, given that GURPS already gives the vast majority of historical galleys SM +8? Except the SM +9 'turtle ship', of course.

Realistically, attention needs to be paid to matching rowing power on both sides, but there is nothing inherently unrealistic or cinematic about scaling the motive power generated by each rower by his strength (or indeed, by some combination of strength and skill).

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

Hmmm... thanks for that.

This would seem to allow the building of penteconters or even more advanced models of war galleys in quite a short time.

Good for the PCs now, as it means that their allies in Messemprar will have been able to make use of the months while their control of the sea ensured plentiful shipping to Messemprar to import as much wood as they require and basically build as much of a navy as they can afford.

Pretty bad for them later since it means that the empire they are facing will require about one third of the time I had estimated to put out a new fleet to replace ships they have sunk or captured. Spending a few dozens of GURPS $ millions on new galleys won't even cause them to blink, their annual naval budget is already some $60,000,000 and that was while they were winning the war and used naval ships just to defend their grain ships from pirates.

Of course, being able to build them quickly won't help the enemy man their ships, as they already suffer from not having had much of a native tradition of seamanship, ocean voyaging, seaborne trade or sea warfare* before this war.

Most of their foreign trade for the past century or two has been transported in foreign hulls and their navy has always been low-prestige and neglected compared to their army. The fact that several nautical disasters and some defeats at sea killed off some 80% of their experienced navy men a few years before the start of this war didn't help.

*At least within the past few centuries.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

I suspect there's a limit to the number of men you can use on a given size of ship. Also, there's the question of the availability of seasoned timber. That doesn't matter much for ships that are expected to be expended in a current conflict, but it is important in peacetime shipbuilding, because seasoning takes months to years, depending on the kind of wood.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

Most certainly. But that limit will not be less than ten for even the smallest war galley, which means that working in shifts, it seems that most war galleys would take less than a month.

Of course, it is highly plausible that triremes or other very fast galleys are actually higher quality than simple cargo ships of comparable tonnage, requiring more hours of work and a higher proportion of skilled man-hours to unskilled.

This is indeed a significant limit for both sides.

For the PCs' allies, it merely means that good warships (as opposed to rafts or scaled-up boats from green wood) require fairly expensive imports of seasoned wood, which imposes the above limit of 'as much of a fleet they can afford'. Being able to trade with all the Inner Sea means not having to cut and season your own lumber, especially as you control rich mines, irrigated plains, coastal land, river valley, huge lake, hills and mountains, but no significant forests.*

The Empire on the other side, however, has already been using all the sources of seasoned timber that they can tap for the last five years. Huge building projects, exponential growth in naval tonnage, truly frightening amounts of ox carts, massive demand for bows, spears, arrows, scorpion bolts, etc.

Any more wood they import would need to be transported through quite a lot of sea lanes controlled by the enemy or alternatively, transported overland for a thousand miles or more.

I've already estimated that a lot of their emergency naval building will use green wood and they've also been scavenging wood from less vital sources to turn out sorely needed hulls to replace losses.

Of course, imperfect raw materials means heavy, slow and clumsy galleys, which leads to further losses at sea.

*The land has been settled for almost 4,000 years, they've all been utilised already.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

If you'd prefer, you could probably use that as a guideline. As a warship, chances are good the number of rowers is more than what are actually required, in order to allow it to more readily soak up casualties. Let's say the ship might be able to lose up to 20 men and still function normally - that puts it at 150, for 50 men per system. The weight of the ship (which is what SS cares about) is appropriate for an SM+6 vessel, so for the sort of performance seen in the article some more appropriate numbers might be 15 (SM+5), 50 (SM+6), and 150 (SM+7). Unfortunately, following this progression we find the penteconter (SM+4 by weight) should need only 10 rowers for its Move 1/4, when in reality it has 50. Maintaining the same percent extras, the penteconter might be able to lose 6 men without losing performance, implying 22 men per system. That implies something like +1 SSR (rather than the above +3 SSR) per +1 SM, for a progression of 30 (SM+5), 50 (SM+6), 70 (SM+7). If we assume a decent number of the slaves on that 420+ men galley (at least, I'm assuming that's a slave galley) have ST less than 10, this progression might work decently well.

Personally, I'd be more inclined to just total up everyone's BL and divide by 20 to determine the effective number of rowers, rather than doing the above log business, but I don't know what gives more realistic values.

Re: [Low-Tech] Landing Craft at TL2 to TL4
 

Realistically, of course, rowers can propel a given craft at Move 2-3 fairly easily, but going faster than that requires extremely specific design goals that include as much length as you can practically attain, radical streamlining in water and as little weight as possible.

Going from Move 2 to Move 3 and from Move 3 to even higher Move scores involves non-trivial diminishing returns in terms of efficiency. Getting the maximum possible rowing speed of Move 5 or so has always been an extremely expensive proposition that requires you to sacrifice most every other consideration for your vessel.

I doubt very much that it's realistic to allow adding just +50% to your number of rowers and the expence of a single additional system to go from a fairly typical galley speed of Move 4 to the highest we have evidence of, for Move 5.

It seems to have been a ground-up redesign that sacrificed nearly everything else for speed and required almost as many rowers as it was theoretically possible to cram in there.