New Equipment: Sonic Spear

[rust]

This one is from my Varuna water world setting, a standard hunting wea-
pon of aquafarmers and dolphineers.

The Sonic Spear is actually more like a short staff, thicker at the rear end
where the power cell is and at the blunt front end where the sound emit-
ter is, and with a grip and a sling for holding it in the middle.

The weapon is 1.50 m long, has a diameter of 6 cm in the middle and 10
cm at the ends and weighs 2.5 kg outside of the water (it has neutral buo-
yancy in the water). The power cell is sufficient for 10 shots, which do 2d6
damage under water, but are only rather irritating in the air. The range of
the weapon is about 10 meters.

Aquafarmers and dolphineers (and occasionally other colonists) use the
Sonic Spear for "spear fishing" single fish when using nets to catch more
than one fish would be unnecessary. It replaced the traditional spear gun,
which is only still used when it is important to have a line connecting the
dart and the spear gun to "haul in" the fish (for example species which be-
gin to sink rapidly once they stop swimming).

 

[asciitraveller]

If one assumes a speed of sound in water of 1500 m/s and a ultrasound frequency of 2 MHz, one wavelength of the infrasound would be 0,75 millimeters. Multiple emitters would fit on the head of the staff in the correct positions to achieve the desired beamforming by interference (the same principle which is used for multi beam sonar today).

So, yes, with good power cells, this weapon works in "sciency" campaigns. Great idea. One little mishap in design: as the wavenlength in air is different, it would only emmit 2 MHz noise in every direction when used in air (which couldn't be heard anyway).

 

[BFalcon]

Wouldn't 2MHz frequency sound still cause nausia when used in air though?

Good idea, rust - if you want more ideas on sonic weapons, check out Terror From the Deep (the second X-COM game) - they had several underwater weapon systems (the whole game, nearly, was based underwater).

Rather than a spear, maybe a Trident? Each prong could be the sonic beam emitter and if the prongs were arranged in a triangular shape (as seen from the tip), the focal point would be easy to gauge for precise use if need be, while having a very nautical look (a trident being a very traditional nautical symbol in Terran culture).

As for the science, I agree - the idea is very sound (pun intended) - you may want a shield around each prong's emitter to attempt to deaden the sound spreading in unwanted areas and upsetting their users (especially those of Dolphin descent), but those would probably be integral to the prongs themselves.

 

[rust]

Wouldn't 2MHz frequency sound still cause nausia when used in air though?

I imagine it similar to a slap, quite unpleasant and irritating, but below
the threshold were it would stun or damage enough for game mechanics
purposes.

Rather than a spear, maybe a Trident?

I thought about it, but it would not quite fit in with the colonists' "design
philosophy", their gear uses "smooth" design wherever possible, to pre-
vent the equipment from getting tangled with nets, lines and thelike.

 

[BFalcon]

Wouldn't 2MHz frequency sound still cause nausia when used in air though?

I imagine it similar to a slap, quite unpleasant and irritating, but below
the threshold were it would stun or damage enough for game mechanics
purposes.

Still worthy of a negative DM for a while though I suspect... since the inner ear is the part of the body related to balance, it might be enough to cause lasting nausia and vertigo if used right, even if it's only mild... including through EVA suits (they're not usually made to be soundproof since they don't need to be - indeed, helmet contact is a "known" sci-fi method of private or emergency communication between EVA-suited crew... of course, you may need to make contact with the helmet for the full effect...

Rather than a spear, maybe a Trident?

I thought about it, but it would not quite fit in with the colonists' "design
philosophy", their gear uses "smooth" design wherever possible, to pre-
vent the equipment from getting tangled with nets, lines and thelike.

Fair enough... although the Trident/net combination must have been used historically for a reason...? But I fully agree with your reasoning - it makes sense...

 

[barnest2]

As far as I remember, the trident was used mainly because the prongs could be used to trap an opponents weapon, which isn't as useful here.
Also, the net was obvious I hope...

 

[BFalcon]

As far as I remember, the trident was used mainly because the prongs could be used to trap an opponents weapon, which isn't as useful here.
Also, the net was obvious I hope...

Trident: Ah ok, wasn't sure if it was that, the reach (ie being able to reach an opponent before he could regain his feet, after sweeping the legs with the net) or the ability to reach through the net...

Net: Nah... care to elaborate?

 

[barnest2]

Well the reach is just as useful with a spear, so... yeah, its trapping and disarming.

The net would be used to grab and trap the opponent, his weapon arm, his legs, even his head. Its reasonably hard to get yourself out of a net once your in it, so its very good for trapping a person. And once they're tangled or on the floor... well, they pretty much have to give in.

The retiarii (those armed like this) were unusual, and more rare compared to myrmillonis and the like, and were only really matched against Secutores (who were armoured specifically to fight a man armed with a trident)

 

[BFalcon]

Erm.. I was actually being a little cheeky/sarcastic with regards the net, but thanks...

 

[barnest2]

Erm.. I was actually being a little cheeky/sarcastic with regards the net, but thanks...

Ah... sorry

 

[rust]

Completely unrelated, but I do not want to start a thread because of one
translation problem: Is there a specific English word for an inflatable life
boat (like the ones carried on aircraft) to distinguish it from a boat with
a rigid hull ?

Thank you.

 

[BFalcon]

As far as I know, just an Inflatable Life Raft, although I think the Zodiacs are inflatable and do lend their names to the boats sometimes, but they are usually rigid-bottomed (I think)...

Generally, a boat is pointed at the bow, a life-raft isn't (and may be another shape than square too) and the raft is the more commonly-carried for survival use (where endurance is more important).

Barnest: No worries... no apologies needed.

 

[Dave Chase]

Completely unrelated, but I do not want to start a thread because of one
translation problem: Is there a specific English word for an inflatable life
boat (like the ones carried on aircraft) to distinguish it from a boat with
a rigid hull ?

Thank you.

No, not really.

There are name brand ones that might work, but no generic Single word descriptions.

I might suggest call them IRaft for Inflatable Life Raft. Then it's all yours (name wise).

Dave Chase

 

[rust]

Thank you very much, BFalcon and Dave, this solved my problem.

In German the thing is called a "Rettungsinsel" (= "rescue island"), but it
was impossible to find any information on the Internet with a translation
of that, and little with "life boat" - "life raft" was the key, I now have all the
information I was looking for.

 

[BFalcon]

Ah wait - try "Inflatable Dinghy" too... just thought...

And you're welcome

 

[barnest2]

A RHIB works as well, its commonly used as a term in navies and maratime services...

 

[rust]

A RHIB works as well, its commonly used as a term in navies and maratime services...

Yes, indeed - a lot more Internet material under RHIB. :shock:

Thank you very much.