Steve Jackson Games - Site Navigation
Home General Info Follow Us Search Illuminator Store Forums What's New Other Games Ogre GURPS Munchkin Our Games: Home

Go Back   Steve Jackson Games Forums > Roleplaying > GURPS

Reply
 
Thread Tools Display Modes
Old 11-18-2015, 10:15 AM   #1
Icelander
 
Icelander's Avatar
 
Join Date: Mar 2006
Location: Iceland*
Default Low-Tech Weapons and Tools Underwater

After one of the PCs in my fantasy captain encountered Baron Ak'Zuma, the local lord of the fearsome sahuagin, also known as sea devils or shark-men, he wanted to know what TL2 to TL4+1 materials would make for the best tools and weapons to trade to a race who lives underwater, in salt water.

Coral spearheads or knives may be sharp, but they are more or less single use. Bone spearheads, weapons or tools are sub-par. Magical enchantment can easily produce waterproof tools and weapons that are equal or even superior in durability and strength as steel, but is very expensive.

What non-magical methods are available to surface dwellers to produce tools and weapons that are worth trading to undersea races?

Metals will rust or corrode over time. Granted, even if a metal spearhead corrodes or rusts into uselessless within a year of hard use, that's still a an improvement over a coral spearhead that breaks the first time you hit bone while killing a whale or sea serpent.

What metals provide the optimum balance between corroding or rusting slowly underwater and having desirable properties compared to bone or coral?

Is there a meaningful difference between the durability of copper, brass or armour- (or weapon-) grade bronze under water? Does steel last longer than bronze or does rust ruin items faster than corrosion? Is steel better or worse than wrought iron?

Are there non-magical alloys possible with TL4 technology that would be worth the extra trouble of making them, in terms of durability and quality?

What about TL4+1 metallurgy, provided with a dormant volcano enchanted with a system for trapping magical fire, melting metals, mixing them and purifying? Research might yield TL4+2 metallurgy from that magic.

How hard is it to make stainless steel if you have the Measurement spell, high skill at Metallurgy/TL4+1 and a way to melt iron down to liquid form?

Assume that sahuagin live at depths of 100' to 1,500' in a subtropical salt ocean, generally fairly close to shore. It might be possible to store tools and weapons between uses under slightly difference conditions, if it is worth it, but the lifestyle of sahuagin is generally very mobile, with males hunting, raiding or patrolling almost constantly while they are awake.
__________________
Za uspiekh nashevo beznadiozhnovo diela!
Icelander is offline   Reply With Quote
Old 11-18-2015, 10:19 AM   #2
Anthony
 
Join Date: Feb 2005
Location: Berkeley, CA
Default Re: Low-Tech Weapons and Tools Underwater

The most obvious option is bronze; tin bronzes are reasonably corrosion resistant.
__________________
My GURPS site and Blog.
Anthony is online now   Reply With Quote
Old 11-18-2015, 10:45 AM   #3
Icelander
 
Icelander's Avatar
 
Join Date: Mar 2006
Location: Iceland*
Default Re: Low-Tech Weapons and Tools Underwater

Quote:
Originally Posted by Anthony View Post
The most obvious option is bronze; tin bronzes are reasonably corrosion resistant.
Including most typical TL1 tool, weapon and armour tin bronze alloys?
__________________
Za uspiekh nashevo beznadiozhnovo diela!
Icelander is offline   Reply With Quote
Old 11-18-2015, 10:54 AM   #4
Anthony
 
Join Date: Feb 2005
Location: Berkeley, CA
Default Re: Low-Tech Weapons and Tools Underwater

Quote:
Originally Posted by Icelander View Post
Including most typical TL1 tool, weapon and armour tin bronze alloys?
Tin bronze is pretty resistant to seawater, yes, unless you had something that produced a galvanic effect. Some early bronzes would be arsenic bronzes which are less resistant.
__________________
My GURPS site and Blog.
Anthony is online now   Reply With Quote
Old 11-18-2015, 12:25 PM   #5
johndallman
Night Watchman
 
Join Date: Oct 2010
Location: Cambridge, UK
Default Re: Low-Tech Weapons and Tools Underwater

Quote:
Originally Posted by Icelander View Post
Including most typical TL1 tool, weapon and armour tin bronze alloys?
The Antikythera mechanism is still recognisable after 2000 years in the sea.

More recently, copper sheathing for ships was proposed at late TL4 and implemented in early TL5, which I suspect was when thin copper sheet could be made cheaply enough. Copper does not corrode in sea water, although it very slowly dissolves: ship sheathing had to be replaced after a decade or so as it wore thin at places where water moved at high velocity over a hull. Copper will also slowly leach from some alloys, such as Muntz metal, a high-zinc brass that was cheaper than copper.

Tin bronzes should last long enough to be useful.
johndallman is offline   Reply With Quote
Old 11-18-2015, 12:39 PM   #6
(E)
 
Join Date: Jul 2014
Location: New Zealand.
Default Re: Low-Tech Weapons and Tools Underwater

Aluminium might squeeze in to TL4 + 1.

Resins and fibre products could be valuable.
__________________
Waiting for inspiration to strike......
And spending too much time thinking about farming for RPGs
Contributor to Citadel at Nordvörn
(E) is offline   Reply With Quote
Old 11-18-2015, 01:04 PM   #7
weby
 
weby's Avatar
 
Join Date: Oct 2008
Default Re: Low-Tech Weapons and Tools Underwater

Quote:
Originally Posted by Icelander View Post
What non-magical methods are available to surface dwellers to produce tools and weapons that are worth trading to undersea races?
Metals will rust or corrode over time. Granted, even if a metal spearhead corrodes or rusts into uselessless within a year of hard use, that's still a an improvement over a coral spearhead that breaks the first time you hit bone while killing a whale or sea serpent.

What metals provide the optimum balance between corroding or rusting slowly underwater and having desirable properties compared to bone or coral?
It really depends on the actual knowledge level and the willingness to experiment and such. A lot of things that have to do with corrosion resistance first appeared in 1800s, but some of it came into widespread use only much later. As examples cathodic protection system in test use from early 1800s (tl5) and chromium steels first noted to be better at resisting things in early 1800s(tl5), but first almost stainless steels from late 1800s(tl6) in their first appearances, but making the things to be actual products will require experimentation. Both ideas took more than 100 years from the first tests to wider use in real life.

Note that in terms of saltwater resistance of steels at least corrosion tends to be the bigger problem and rust a lesser(but significant).

Quote:
Is there a meaningful difference between the durability of copper, brass or armour- (or weapon-) grade bronze under water? Does steel last longer than bronze or does rust ruin items faster than corrosion? Is steel better or worse than wrought iron?
Different alloys make a lot of difference, so a bit depending on your technology, but most metals actually tend to survive a while in water.

I do not know about bronze, but the copper sheathing proved fairly long lasting in ships (though as the corrosion process was not understood, the iron bolts had significant corrosion issues on the early experiments). Copper has a self protecting feature from corrosion where a less reactive surface forms protecting from corrosion. Iron does not form such (at least to a significant degree).

And if you have a sacrificial anode to corrode away the corrosion is reduced to a small fraction.
"You need to buy these magic iron talismans to fasten to your copper spear so it lasts longer"
"You need to buy these magic zinc talismans to fasten to your steel spear so it lasts longer"
All without any magic...

Quote:
Are there non-magical alloys possible with TL4 technology that would be worth the extra trouble of making them, in terms of durability and quality?
Not really.

Quote:
What about TL4+1 metallurgy, provided with a dormant volcano enchanted with a system for trapping magical fire, melting metals, mixing them and purifying? Research might yield TL4+2 metallurgy from that magic.
A lot of it depends on what your +1 means in terms of divergence.

If you have the ability to create very low carbon steel and have chrome available you may be able to create an alloy with enough chrome to be a proper stainless steel. Historically it was not until the aluminothermic(spelling?) reduction process for producing carbon-free chromium appeared just before 1900 that it could be done.

Quote:
How hard is it to make stainless steel if you have the Measurement spell, high skill at Metallurgy/TL4+1 and a way to melt iron down to liquid form?
It really is a question of knowing how to make chromium alloys of iron. The hard part getting the carbon content low enough (and of course to know that you need to do that).

A lot of the things finally making "proper" stainless steel reality came from other TL6 developments and like most other science was a collaborative effort where one scientist discovers one thing and some other something else based on that.

So depending on the cinematic level of you campaign(Ie. how close to quick gadgeter do you want to go), you should judge the probability of a single person coming up with all the needed parts.
__________________
--
GURPS spaceship unofficial errata and thoughts: https://gsuc.roto.nu/
weby is offline   Reply With Quote
Old 11-18-2015, 01:06 PM   #8
lwcamp
 
lwcamp's Avatar
 
Join Date: Nov 2004
Location: The plutonium rich regions of Washington State
Default Re: Low-Tech Weapons and Tools Underwater

In addition to corrosion, there's also biofouling. You would need to clean the blade regularly to avoid a buildup of barnacles, corals, polyps, mussels, calcerous tube-worms, and other clingy sea-life, while shipworms would eat away at any wooden hafts. Copper is known to resist biofouling - it is somewhat toxic, particularly to invertebrates, and living things don't like to grow on it. I don't know how copper alloys (bronzes) compare.

Luke
lwcamp is offline   Reply With Quote
Old 11-18-2015, 01:43 PM   #9
evileeyore
Banned
 
evileeyore's Avatar
 
Join Date: Jul 2006
Location: 100 hurricane swamp
Default Re: Low-Tech Weapons and Tools Underwater

If you're looking for other good trade goods, there is glass containers.

Glass blades may not be perfectly durable, but for 'kitchen' tool use they'd be great for under sea dwellers.

Volcanic rock might already be known to the shark-people, or maybe not. For that matter fire treated flint would be a vast improvement to corral weapon tips.
evileeyore is offline   Reply With Quote
Old 11-18-2015, 03:49 PM   #10
Vargant
 
Vargant's Avatar
 
Join Date: Oct 2014
Location: Germany
Default Re: Low-Tech Weapons and Tools Underwater

Just as evileyore already stated:
Obsidian might be interesting. It was good enough for the meso-american civilisations. If they can get near underwater-volcanoes, your shark men might be able to collect obsidian shards and make them into useful tools and weapons.

Well thats at least the way I handle tools for fishmen in my setting. Obsidian, sharkteeth/shells, rocks and corals. Oh and maybe ceramic blades.
Vargant is offline   Reply With Quote
Reply

Tags
forgotten realms, low-tech, metallurgy, underwater

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Fnords are Off
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 12:12 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.