Sub 100 ton tugs and man G when tugging!

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hiro

Sub 100 ton tugs and man G when tugging!

Postby hiro » Wed Aug 05, 2015 1:01 am

OK, I've looked thru HG2 trying to work this one out but to no avail, before I get my slide rule out and try fudging some house rules, is anyone aware of published rules or have you house ruled, for a sub 100 dton ship with drives from HG2's small drives table on page 58 when grappled to a ship that takes their sum displacement to more than 100dT? (the largest ship on the table). The rules for grapples on page 45/46 of HG don't shed any light on this.

Did I miss it somewhere?

ta
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Re: Sub 100 ton tugs and man G when tugging!

Postby GypsyComet » Wed Aug 05, 2015 2:00 am

You've tripped over one of the reasons why I prefer to have options to the letter drive paradigm. It breeds "special" rules around the edges...
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Re: Sub 100 ton tugs and man G when tugging!

Postby dragoner » Wed Aug 05, 2015 2:15 am

I'd figure the percentage of G's when adding the extra tonnage, then use that number as multiplier on the transit time if I wanted to be picky, otherwise just handwave it and say min 1G, and figure times on that.
hiro

Re: Sub 100 ton tugs and man G when tugging!

Postby hiro » Wed Aug 05, 2015 3:36 am

If only they'd thought about integrating the design sequences...

If only they'd thought

And no, I didn't start this thread to whine as I often have about the lack of "Big Picture" in MgT...
hiro

Re: Sub 100 ton tugs and man G when tugging!

Postby hiro » Wed Aug 05, 2015 4:39 am

Dragoner, thanks for the direction, I'll dust off the slide rule and have a go...

Gypsy Comet, do you have house rules you're using?
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Re: Sub 100 ton tugs and man G when tugging!

Postby dragoner » Wed Aug 05, 2015 5:36 am

hiro wrote:Dragoner, thanks for the direction, I'll dust off the slide rule and have a go...
I'd probably just do the actual numbers if you have them, but it is simple math. Say a 40 ton ship with 1G maneuver, pushing a 100 ton ship, adding them together is 140 tons; divide the original by the 140 (40/140=.29). 1*.29, means you now have .29G maneuver, using the continuous thrust times calculator, going a million km at 1G with turnover is 5 hours 36 minutes, at .29G it is 10 hours 25 minutes. It's your call how you want to do it.
hiro

Re: Sub 100 ton tugs and man G when tugging!

Postby hiro » Wed Aug 05, 2015 5:49 am

D, I was going to design a tug for the game we've discussed but I started off by looking for one in the published books I own. Found the 30 ton tug on page 94 of HG. It has a whopping man-14! Amusingly it doesn't appear to have a docking clamp as per page 45/46 of HG.

I'll work out the math when I'm not about to sleep!
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Re: Sub 100 ton tugs and man G when tugging!

Postby dragoner » Wed Aug 05, 2015 5:55 am

That is amusing in that you would want to be clamped and pushing rather than towing with a strap or cable, to avoid some Newtonian gymnastics. You might want to bump the difficulty on the pilot roll, maybe allowing a task chain DM from how it is rigged together. My Cr0.02.
hiro

Re: Sub 100 ton tugs and man G when tugging!

Postby hiro » Wed Aug 05, 2015 5:59 am

I won't use that ship, it's silly. The blurb with the ship makes mention of the ship docking in order to then tow/push it's "target" but its annoying to miss a rule the same book the design is published in introduces. With the size of the drive and power plant there's no space left for a docking clamp big enough to use all those 14G of manoeuvre.
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Re: Sub 100 ton tugs and man G when tugging!

Postby dragoner » Wed Aug 05, 2015 6:05 am

Probably just as good to use a ship's boat or shuttle rigged with a clamp, the more the dtons the better.
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Re: Sub 100 ton tugs and man G when tugging!

Postby GypsyComet » Wed Aug 05, 2015 6:15 am

hiro wrote:Gypsy Comet, do you have house rules you're using?
While I have not gone diving into the subcraft rules particularly, my first thought would be to compare the drive size in tonnage to the core book letter drives. If you meet those sizes, you get those performances.

That Tug has 16 dtons of M-Drive, the equivalent of an H MDrive. It should be able to push around a lot of ship.
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Re: Sub 100 ton tugs and man G when tugging!

Postby Condottiere » Wed Aug 05, 2015 9:52 am

If you're using alphabet drives, each staged smallcraft one represents twenty tonnes of thrust, so thrust over tug plus object, maximum sZ at four hundred eighty.

Space Station indicates one tenth grav thrust viable.
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Re: Sub 100 ton tugs and man G when tugging!

Postby AndrewW » Wed Aug 05, 2015 10:19 am

hiro wrote:If only they'd thought about integrating the design sequences...
Oh they have...
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Re: Sub 100 ton tugs and man G when tugging!

Postby Reynard » Wed Aug 05, 2015 11:18 am

I'm trying to get an idea what type of tug is desired but it sounds like a towboat rather than a docking tug. Cargo barges and towboat equivalents, because of the way Traveller design rules have always worked, would be a combination unit featuring the tug itself and the barge represented by pods with the sum of these units making the whole. To me, saying you want an underpowered small ship to drag much lager units is the same as expecting a recreational cabin cruiser to pull a cargo barge efficiently down a river. More so if that cruiser is trying to put the Queen Elizabeth to the dock.

Traveller actually does address towing a larger vessel in Merchant Prince. It's part of the rules for using an old fashion tow cable but should be usable for towing in general. Try page 114, Tow Cable. The percentage of towed vessel or unit size determines how much thrust is lost. At best, a small craft better have 6gs to be any use since it could haul unit up to 400% of it's size.
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Re: Sub 100 ton tugs and man G when tugging!

Postby Captain Jonah » Wed Aug 05, 2015 2:29 pm

As has been mentioned above, built something that is basically a huge Mdrive and power plant with a bridge attached.

50Dtons with H drive and H power, a cockpit and a few extra bits. A tow cable and you have something that can pull 1500Dtons at 1G, say the ship grade drive and gravity compensator are limited to 5G so it can't turn into a race car.

At 70Dtons it can have a clamp and act as a push / pull unit.

Even as a small craft a few of these can push some fairly heavy ships around, there will be much bigger ones but just two of these can move a 3,000Dton ship at 1G.

Above a certain point you can add jump tugs as well.
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hiro

Re: Sub 100 ton tugs and man G when tugging!

Postby hiro » Wed Aug 05, 2015 3:09 pm

I'm gonna raise an eyebrow on the tow line idea, there's momentum to deal with unless we're getting all Star Trek and using tractor beams, which I don't think is regular TU stuff.

I would assume that the towed ship is under instruction to power its man drive off or to "idle".

There needs to be a solid link between the two ships. Now maybe I'm not using my imagination on what a tow line is in this case, I'm sure it's not a piece of shock cord but...
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Re: Sub 100 ton tugs and man G when tugging!

Postby Reynard » Wed Aug 05, 2015 4:53 pm

It's not as if the tow ship and the towed unit are being buffeted around. Steady acceleration and a planned course means the lines remain taunt. For the halfway turnaround, the tow disengages the tow cable, flies behind, reattaches and applies thrust again. Still, I don't see the tow cable system a regular feature in tow and docking operations but can act as part of emergency service to distressed vessels for low economic worlds. Bubba's Tow and Bait Shop on Arctus.
hiro

Re: Sub 100 ton tugs and man G when tugging!

Postby hiro » Wed Aug 05, 2015 6:19 pm

AndrewW wrote:
hiro wrote:If only they'd thought about integrating the design sequences...
Oh they have...
Put up or...

:mrgreen:

When?

Vapourware?
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Re: Sub 100 ton tugs and man G when tugging!

Postby AndrewW » Wed Aug 05, 2015 7:27 pm

hiro wrote:When?
Oh been thought about for years.
hiro wrote:Vapourware?
Nope.
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Re: Sub 100 ton tugs and man G when tugging!

Postby Condottiere » Wed Aug 05, 2015 7:41 pm

Towing is an emergency measure; clamping is where it's at.

And if not, you might want to consider:

The scoop includes anti–gravity baffles to minimise the impact but using a scoop with a high relative velocity is not recommended.

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