IMTU - Docking Arms Revised (rough draft)

[phavoc]

So docking arms bugged me enough to write my own interpretation of them. Here's my first rough pass of it. It's not complete (I plan on adding in some personnel/cargo transfer vehicles as well to service starships that aren't docked, but are stooging around nearby and want to move people and things back and forth. I'll be incorporating automated and piloted versions).

I posted separately the question about how (or should) the tonnage for the concourses be added in or not. As it stands I did put in tonnage that would be added to the station for the separate types of docking arms. The one question is what to do about docking arms attached to concourses, if the concourse itself doesn't add it's tonnage to the station.

My questions are:
(1) Is this too detailed? I personally like good explanations that make sense.
(2) Does it seem reasonable? If you read this to your players would they get it?
(3) Do the numbers (size, cost, displacement) make sense compared to the functionality?
(4) What am I missing (aside from what I've already touched on)?

Feedback is appreciated.

So here it is: Docking Arms Revised

Type 1 – The purpose of the Type 1 docking arm is to allow for ships to take on fuel and life support gases without having to take up a full docking port or hangar. Ships that utilize a Type 1 docking arm are also able to draw upon the stations power grid if they need to shut down their own power plant for maintenance. If the ship does not have its own small craft to transfer personnel and/or cargo it can utilize the small shuttlecraft provided by the station to do so. The primary advantage of a Type 1 docking arm is its price – ¼ the standard cost. This appeal's to a number of traders on a budget. They are also used by ships that are just passing through and looking only to refuel. Each Type 1 docking arm requires 10 Dton’s internal displacement and can extend as much as 100 meters from the station. Due to the need to keep the space around a station relatively uncluttered and free, a station may install a Type 1 docking arm to its external hull for every 500 tons of displacement. Cost is MCr.5.

Type 2 – A Type 2 docking arm allows for the safe transfer of passengers and personnel between stations and ships. There are two variations, a (small, 3m wide x 3m tall) that are intended for ships 100 through 1,000 tons and a (large, 4.5m wide x 3m tall) that services ships greater than 1,000 tons. Each docking arm includes the same fuel/power/life support gases interface of a Type 1 docking arm. Segments come in 10m lengths and up to five sections may be joined together to make up a single segment. A rotation joint may be added to a 50m segment to allow an additional 50m to be added. The rotational joint allows the segment furthest from the station to rotate in a 180 degree arc. Each segment displaces 10 Dton’s and can be sealed in the event of an emergency or breach. The segment end that attaches to the ship includes an airlock. A small Type 2 docking arm requires 15 Dton’s space for external attachment points and machinery. A large docking arm requires 20 Dton’s. Cost is MCr 1.5 for the small and MCr 2.0 for a large.

Type 3 – Type 3 docking arms function exactly the same as Type 2 (including having two sizes), with the exception of purpose and size. Type 3 arms are meant primarily for cargo transfer, so they are more utilitarian than Type 2. There are motorized pulley tracks on the ceiling that can be used to grab and move pieces of cargo up or down the segment. In addition the floors have sets of rollers to roll on/roll off cargo. As in starships, ground crews may also adjust the gravity in individual segments. (Small) docking arms are 4.5m wide by 6m tall and (large) Type 3 docking arms are 9m wide x 6m tall. There are very few cargo ships that cannot be accommodated by a cargo docking arm. A small Type 3 docking arm requires 25 Dton’s space for external attachment points and machinery. A large docking arm requires 50 Dton’s. Cost is MCr 2.5 for the small and MCr 5.

Note – All types of docking arms may be installed at ground installations for use in vacuum, hazardous or undersea environments.

Note – As a general rule, docking arms and docking concourses are not armored and are not intended to be utilized while combat is ongoing. They are considered “hull” hits on the external hit table and are considered destroyed if hit. A hit on a docking concourse will destroy all attached docking arms and transfer vehicle docks for that specific concourse section. Referees may also consider randomly assigning hits to docking arms and/or docking concourses each time a hull hit occurs. This reflects their relatively unarmored and delicate status.

Docking Concourse – Some stations may require a large number of docking positions without actually needing to provide additional station tonnage, especially stations that support large numbers of itinerant craft, such as a mining station. A docking concourse allows a station to increase the number of docking points (they support both docking arms and transfer vehicle docks) without impacting the station’s internal tonnage by extending large corridors (like a modern day airport’s gate concourses) away from the station. Docking concourse are generally specialized – they either only support personnel or cargo. Some smaller stations or those that cater primarily to workers only mix the type of docking arms on a single corridor. Concourses are purchased in 100m lengths; they are 10.5m wide and 6m tall. Each segment can be individually sealed off from the station or additional segments if necessary. They cost 1MCr per concourse segment (plus the cost of each installed docking arm or transfer vehicle dock) and add 462 Dton’s to the tonnage of the station. However they should not be added to overall displacement of the station when making crew or other calculations based on final tonnage.

Docking arms and transfer vehicle points may be installed per the chart below.
<500 tons – 10 per 100 m (one vessel every 20m per side)
500 – 1,000 tons – 4 per 100m (one vessel every 50m per side)
1,000 – 5,000 tons – 2 per 100m

 

[simonh]

The attachment points for small bad large type 2 arms differ in tonnage, but it looks like 10m sections of both sizes are 10 dtons. I'd have expected the large size sections to be 15 dtons.

It might be clearer if small and large type 2 arms are split into being different types for clarity.

Simon Hibbs

 

[Infojunky]

I have to say this has got my brain working, just need to find a end to pull on....

 

[phavoc]

The attachment points for small bad large type 2 arms differ in tonnage, but it looks like 10m sections of both sizes are 10 dtons. I'd have expected the large size sections to be 15 dtons.

It might be clearer if small and large type 2 arms are split into being different types for clarity.

Simon Hibbs

I will consider that. It would keep things to scale better.

I was also thinking it might be better to just make the Type 2 the "small", and the Type 3, the "large", and drop the idea of separate passenger and cargo connections. I would think you'd have specialized versions of each (we do today). However from a gaming perspective it may be unnecessary noise, as players/ref's could care less about aesthetics, they just want something that works and they can blow up.

 

[phavoc]

I think I will be revising the descriptions and making 3 types, with Type 2 being the smaller, and type 3 being the larger. Price will be fixed, and I'll drop the lengths and such. Most players and ref's won't need or care for it, but for the people like like hyper details, I'll keep the description portion and drop in a table that allows that group to build them.

After thinking about it more I don't believe mucking up the station data sheet with 200m docking arms (small, passenger), 50 m docking arm, etc does anybody any good.

 

[Infojunky]

Ok this is a thought, you might want to consider your basic shapes. Generally when I think about Docking arms, Docking Rings and Airlocks it is terms of standard sizes. A through deck 1.5 meter floor hatch/valve based docking ring is a 2 meter docking ring as that is the size a round docking apparatus is for that size hatch. The basic visual from the outside is a square within a circle....

My reasoning about using simple regular polygons is that there is more rotational freedom at the docking point.

 

[sideranautae]

I think I will be revising the descriptions and making 3 types, with Type 2 being the smaller, and type 3 being the larger. Price will be fixed, and I'll drop the lengths and such. Most players and ref's won't need or care for it, but for the people like like hyper details, I'll keep the description portion and drop in a table that allows that group to build them.

After thinking about it more I don't believe mucking up the station data sheet with 200m docking arms (small, passenger), 50 m docking arm, etc does anybody any good.

Can't wait. This is neat system you came up with.

 

[Rikki Tikki Traveller]

I would suggest modifying the Type 1 a bit. Instead of needing a shuttle, allow the use of a flexible umbilicle line. No artificial Gravity, no armour protection, just a semi-transparent plastic tube... High Passengers will NOT use this method.

At Type 2, you get a REAL umbilicle with artificial gravity and a bit of protection (at least against small arms fire), but not much.

Looks good though

 

[phavoc]

First off, thanks to everyone for the feedback. I've gone back and revised and, I think, simplified the docking arm concept. It's not three distinctive types, and I kept the idea of docking concourses. I also added in armoring them if you wanted. Also based on comments I created an automated transfer vehicle, though I didn't properly flesh out the design because it's really just a glorified space taxi and I was in a hurry. . I'm sure there is something missing still...

Docking Arms Revised
Type 1 – The purpose of the Type 1 docking arm is to allow for ships to take on fuel, water, life support gases and dispose of any needed waste without having to take up a full docking port or hangar. Ships that utilize a Type 1 docking arm are also able to draw upon the stations power grid if they need to shut down their own power plant for maintenance. If the ship does not have its own small craft to transfer personnel and/or cargo it can utilize the small shuttlecraft provided by the station to do so. The primary advantage of a Type 1 docking arm is its price – ¼ the standard cost for docking at a station. This appeal's to a number of traders on a budget. They are also used by ships that are just passing through and looking only to refuel. Each Type 1 docking arm requires 10 Dton’s internal displacement and can extend as much as 100 meters from the station. Due to the need to keep the space around a station relatively uncluttered and free, a station may install a Type 1 docking arm to its external hull for every 500 tons of displacement. Cost is MCr.5.

Type 2 – A Type 2 docking arm allows for the safe transfer of passengers and cargo between stations and ships. These docking arms are intended to interface with ships of 2,000 Dtons or less. The interior is relatively roomy and is sufficiently sized to allow two-way passenger traffic as well as most containerized and oversized bulk cargos. Each docking arm includes the same umbilical connections as a Type 1 docking arm. A Type 2 docking arm is 10m long retracted and can extend up to 50m from a stations hull. They are 4.5m wide x 4m tall. The connection end is equipped with dual airlock doors for safety, approximately 1m in depth. A Type 2 docking arm requires 20 Dton’s internal displacement and costs MCr 2.0.

Type 3 – Type 3 docking arms are used primarily for allowing cargo transfers between stations and ships in excess of 2,000 Dtons. Unless it is dedicated for cargo (many, but not are), the interior is far more utilitarian than a Type 2 arm. In addition, while the Type 3 includes the same umbilical and air lock safety features as a Type 2, it also includes retractable cargo moving equipment in the floor as well as support for motorized container loading/unloading machinery. It is capable of loading/unloading 80 12 Dton containers/hr. As with starships, the deck plating’s gravity controls are adjustable. Type 2 docking arms are much larger (9m wide x 6m tall), can be retracted to a minimum length of 25m and can extend out to 100m. They require 100 Dton’s of internal displacement for machinery and cost 5MCr.

Docking Concourse – Some stations may require a large number of docking positions without actually needing to provide additional station tonnage, especially stations that support large numbers of itinerant craft, such as a mining station. A docking concourse allows a station to increase the number of docking points (they support both docking arms and transfer vehicle docks) without impacting the station’s internal tonnage by extending large corridors (like a modern day airport’s gate concourses) away from the station. Docking concourse are generally specialized – they either only support personnel or cargo. Some smaller stations or those that cater primarily to workers only mix the type of docking arms on a single corridor. Concourses are purchased in 100m lengths; they are 10.5m wide and 6m tall. Each segment can be individually sealed off from the station or additional segments if necessary. They cost 1MCr per concourse segment (plus the cost of each installed docking arm or transfer vehicle dock) and add 462 Dton’s to the tonnage of the station. However they should not be added to overall displacement of the station when making crew or other calculations based on final tonnage. Docking arms and transfer vehicle points may be installed per the chart below.

<500 tons – 10 per 100 m (one vessel every 20m per side)

500 – 1,000 tons – 4 per 100m (one vessel every 50m per side)

1,000 – 5,000 tons – 2 per 100m

>5,000 tons – 1 per 100m

Note – All types of docking arms may be installed at ground installations for use in vacuum, hazardous or undersea environments.

Note – As a general rule, docking arms and docking concourses are not armored and are not intended to be utilized while combat is ongoing. They (Type 1 cannot be armored) may be armored to the stations armor factor by multiplying their base price by 4x. They are considered “hull” hits on the external hit table and are considered destroyed if hit (armored docking arms will ignore 1 out of every three hull hits). A hit on a docking concourse will destroy all attached docking arms and transfer vehicle docks for that specific concourse section. Referees may also consider randomly assigning hits to docking arms and/or docking concourses each time a hull hit occurs. This reflects their relatively unarmored and delicate status.

Crew Transfer Vehicle (CTV)
A small 10 Dton automated vehicle that ships in parking orbit (up to 50km) may call from stations. The CTV will rendezvous with the requesting vehicle, automatically dock to their primary airlock and shipboard personnel can board and return to the station. For safety purposes and because of the short distances, a CTV is capable of only 1/4G acceleration, more than sufficient for it’s primary task. Internally the CTV consists (from front to rear) of a 1Dton airlock, rack space with safety netting for up to 1.5 Dton of hand-carried cargo, and seating for 24 (set in 2x2 with two rows in between). At the rear of the craft 1.5 Dtons is set aside for the powerplant, lifesupport and engines. The cost is Cr50 per one-way trip. A CTV dock may be installed on a station or docking concourse (by consuming one vehicle transfer point) for MCr 2.5

Note – Larger automated versions (some with options to be manned) are available, including dedicated cargo and passenger variants, up to 100Dtons displacement.

 

[Infojunky]

Looks good on the 1st read through....

 

[DivineWrath]

I think it looks good as well. It seems to read better than the first draft. I'll give it another read later. That said I'm having trouble with the Docking Concourse so you might want to recheck that.

 

[phavoc]

I think it looks good as well. It seems to read better than the first draft. I'll give it another read later. That said I'm having trouble with the Docking Concourse so you might want to recheck that.

What kind of trouble?

 

[DivineWrath]

I've had some time to think about it and reread the material a few times.

1. At first, I thought the chart had something to do with the station size, as in that the larger the station got, the fewer ships a Docking Concourse could handle. For instance, if the station was larger than 5000 tons, then it could only handle 1 ship per 100m of concourse

However, now that I've had some time to think about it, maybe it was something to do with the size of the ships intended to dock with the concourse. For instance, if you had a concourse rated for <500 tons, then you can dock 10 ships (< 500 tons) per 100m.

Perhaps you should clarify what the chart applies to.

2. Why 462 tons for a concourse? That is an odd number to work with. Could you explain how you got that number and justify why it is that big? When you get to the range of > 5000 tons, you are effectively spending 462 tons to get an advantage you could get if you increased the station hull size by 500 tons.

3. Does the 1 arm per 500 tons limit mentioned in the Type 1 arm apply to the other arms as well? For instance, if you had a 2000 ton station, then you could install 4 type 1s, 4 type 2s, or 2 type 1 and 2 types 2, some other combination of docking arms. You may have put too much details in the type 1 write up instead of docking arms in general.

Am I correct to assume that this limit doesn't apply to the concourse since it is already so large to install and exists primarily to increase the number of arms that a station might have.

4. I think the type 1 should also mention that it has other misc equipment in addition to air, fuel, and power. So long as it had nothing to do with transporting people and cargo to and from the station. I'm thinking misc stuff can cover things that don't need a write, so long as it might exist like a hardline data connection in case you don't want to transmit something over a radio frequency.

 

[phavoc]

I've had some time to think about it and reread the material a few times.

1. At first, I thought the chart had something to do with the station size, as in that the larger the station got, the fewer ships a Docking Concourse could handle. For instance, if the station was larger than 5000 tons, then it could only handle 1 ship per 100m of concourse

However, now that I've had some time to think about it, maybe it was something to do with the size of the ships intended to dock with the concourse. For instance, if you had a concourse rated for <500 tons, then you can dock 10 ships (< 500 tons) per 100m.

Perhaps you should clarify what the chart applies to.

Good point. The concourse is a fixed size (that will answer part of #2 below). The reason I broke it down that way is for two reasons. The first being safety. You'll need a certain amount of clearance for ships to be able to dock, since they come in all shapes and sizes. I didn't run this through a software package like Catia to verify clearances and distances and such. Just tried to keep it reasonable. The second reason was that as the size of the ship went up, it should require more space, hence the spacing has to increase. If you wanted to dock a lot of smaller ships, you can. But if you need the ability to dock bigger ones, you need to have more concourses sticking out to allow the bigger ships more room.

2. Why 462 tons for a concourse? That is an odd number to work with. Could you explain how you got that number and justify why it is that big? When you get to the range of > 5000 tons, you are effectively spending 462 tons to get an advantage you could get if you increased the station hull size by 500 tons.

462 tons turned out to be the tonnage. The corridor had to be wide enough to allow for entry/exit on both sides. And then there needed to be sufficient space between each side for traffic/cargo, etc. Finally there was the height. I could have rounded up, but because the width was 10.5 I came up with the odd number.

The difference in making the station hull 500 tons larger vs. having a docking concourse is the idea that you would be able to only effectively use X amount of space on the hull to dock ships. At least safely. Station hulls are going to have all kinds of protrusions, access points, windows, and even docking arms. You wouldn't cover a station so it would look like an urchin. Concourses allow you to specifically add in docking spaces in areas that are most convenient or conducive to the station and it's local traffic pattern. Plus it makes it easier for ships crews to know where to go coming or going on the station to get to their ship.

3. Does the 1 arm per 500 tons limit mentioned in the Type 1 arm apply to the other arms as well? For instance, if you had a 2000 ton station, then you could install 4 type 1s, 4 type 2s, or 2 type 1 and 2 types 2, some other combination of docking arms. You may have put too much details in the type 1 write up instead of docking arms in general.

That's a good point. And to answer your question, yes, it should apply to all types of docking arms that are attached to the surface of the station. The point of concourses is to eliminate that requirement because it's purpose built to do one thing and one thing only.

Am I correct to assume that this limit doesn't apply to the concourse since it is already so large to install and exists primarily to increase the number of arms that a station might have.

Correct, but I should explicitly state that so there isn't any confusion.

4. I think the type 1 should also mention that it has other misc equipment in addition to air, fuel, and power. So long as it had nothing to do with transporting people and cargo to and from the station. I'm thinking misc stuff can cover things that don't need a write, so long as it might exist like a hardline data connection in case you don't want to transmit something over a radio frequency.

Yes, that was the quandry of putting too much/too little in there. At first it was just fuel and air, then I thought, wait, a ship might want water, to dump waste, to be able to shut down their powerplant so we need electricity. I didn't think about communications, like using station wi-fi. I suppose I just assumed as long as power was going, the communication capability of the ship would work. But being able to hard connect into a stations' intranet would make it possible for ships to try and hack the system through a hardline, as you'd think wireless hacking would be kinda hard, if not impossible in the future. Good idea!

 

[DickTurpin]

I really like where you are going with this, but here are a couple of points to consider. The docking arms could be telescoping, so that when not in use they would occupy less space. 1/3rd less would work well for your current numbers. That way the arms could be installed at their minimum tonnage to save space. When extended, they would temporarily increase the station size, but that should not really matter.

I would also like to see cargo transfer rates for the cargo docking arms.

 

[phavoc]

I really like where you are going with this, but here are a couple of points to consider. The docking arms could be telescoping, so that when not in use they would occupy less space. 1/3rd less would work well for your current numbers. That way the arms could be installed at their minimum tonnage to save space. When extended, they would temporarily increase the station size, but that should not really matter.

They already do telescope out. I didn't want them to be retracted completely, as I thought that would be a bit too much. Also, since they can be used on a docking concourse, there needed to be some logical reason as to why they wouldn't take up internal space as well.

Aaannd... typing that made me realize I left a hole in my logic. A docking arm, on a docking concourse, took up no tonnage. But it still should take up some, even if the machinery and what not is on the outside. So I just fixed that part.

I would also like to see cargo transfer rates for the cargo docking arms.

Ah, I did put the unloading speed in v2 - It is capable of loading/unloading 80 12 Dton containers/hr.

 

[DivineWrath]

Well the point (I think) of explicitly saying air, fuel, and power is to point out that a docking arm, without a doubt, would have those features. Mentioning other misc gear is basically giving the GM the right to say that a docking arm has other stuff as well, and gives the players the right to ask if it has something they want. Basically establish why it is useful and enable others to find more uses for it.

As for the docking concourse, perhaps you could avoid problems by merely stating that it comes equipped with all the docking arms and stuff it needs. It could handle all docking arm types (1, 2 & 3 or maybe types 1 + 2 or 3). It could still serve different ship sizes, the chart would only show how ships can dock at any given time, not what the concourse must be configured for. This of course would mean that the price and size of the concourse would increase to accommodate additional gear. Something to think about.

 

[phavoc]

Well the point (I think) of explicitly saying air, fuel, and power is to point out that a docking arm, without a doubt, would have those features. Mentioning other misc gear is basically giving the GM the right to say that a docking arm has other stuff as well, and gives the players the right to ask if it has something they want. Basically establish why it is useful and enable others to find more uses for it.

As for the docking concourse, perhaps you could avoid problems by merely stating that it comes equipped with all the docking arms and stuff it needs. It could handle all docking arm types (1, 2 & 3 or maybe types 1 + 2 or 3). It could still serve different ship sizes, the chart would only show how ships can dock at any given time, not what the concourse must be configured for. This of course would mean that the price and size of the concourse would increase to accommodate additional gear. Something to think about.

Good ideas. Thanks!