The Two General's Problem

tlb wrote:I am not sure if that matters to a ship that in traveling in a single band (except for going to or coming from normal-space). But if a rogue wave is encountered that required a shift to another band for some time, on return (without a position check in N-space) the assumed position might be wildly off.

Another case we that could be significant would be a ship with streak drive trying to catch a ship with a head start, but a normal hyper-generator. Assuming the heading was known, when the chase ship drops down to intercept, the slower ship might be nowhere to be seen.

Clearly whatever effects there might be are long accounted for for normal impeller/sail powered ships in hyper -- their nav errors just aren't wildly off; they're generally tiny fractions of a percent error. (Compared to the distance they travel through hyper) And we know that ships sometimes do have to change hyper bands to either stick to economically favorable grav waves or to dive under turbulent areas -- and we've heard nothing about that any significant impact to navigation by doing so.

And for spider drives, the Sharks had no problems worth mentioning in getting to their planned insertion point a light-month from Manticore. Now we don't know how accurately they hit it (they did have a ton of margin if they needed it); but I'd think if the spider drive was significantly less accurate in hyper navigation it would have been mentioned as an issue. (Though we've been told so little about it that maybe it just hasn't come up)

Still, the way those drive normally work, each emitter seems to grab for a very short period of time. Just enough to impart a slight pull on the ship before it releases to grab the next anchor point. So if the anchor points moved relative to you that movement would have very little time to affect the ship. Such hypothetical anchor movement seems to me to only be an issue if you did a static hold for some long period.


As for a ship disappearing on your if you try to overfly it using a streak drive -- well that's kind of likely anyway. We don't know how much extra velocity gets bled off going into the Kappa band (though odds are it's around 44%) but the 'speed by hyper band' chart RFC provided shows that just cracking the Iota wall robs a ship of 48% of its velocity (and it'll lose that again coming back down). So while the velocity multiplier in the Iota bands is 20% higher than in the Theta ones the ship'll have to spend significant time working back up towards their previous velocity before that additional velocity multiplier helps enough to let them overtake the estimated position of their quarry. If the other ship was at all aware of the pursuit it would change course or just drop to some other hyper band as soon as the pursuer disappeared -- making it almost impossible to find by the time the pursuer returned.

(And due to the 48% velocity drop dropping back into the Theta bands it wouldn't have to alter course much for the, now slower, pursuer to be unable to pull of an intercept despite dropping out somewhat ahead of their targets estimated position) You can successfully play cat and mouse games to avoid a single pursuer for a long time even if they can access hyper bands that you can't. (All this assuming that you both have the same top speeds -- but if they could go faster than you then they'd likely have just run you down normally, not tried to get the jump by emerging along your projected path)

Jonathan_S wrote:Clearly whatever effects there might be are long accounted for for normal impeller/sail powered ships in hyper -- their nav errors just aren't wildly off; they're generally tiny fractions of a percent error. (Compared to the distance they travel through hyper) And we know that ships sometimes do have to change hyper bands to either stick to economically favorable grav waves or to dive under turbulent areas -- and we've heard nothing about that any significant impact to navigation by doing so.

And for spider drives, the Sharks had no problems worth mentioning in getting to their planned insertion point a light-month from Manticore. Now we don't know how accurately they hit it (they did have a ton of margin if they needed it); but I'd think if the spider drive was significantly less accurate in hyper navigation it would have been mentioned as an issue. (Though we've been told so little about it that maybe it just hasn't come up)

Still, the way those drive normally work, each emitter seems to grab for a very short period of time. Just enough to impart a slight pull on the ship before it releases to grab the next anchor point. So if the anchor points moved relative to you that movement would have very little time to affect the ship. Such hypothetical anchor movement seems to me to only be an issue if you did a static hold for some long period.

That seems to be an argument in vindication of this statement:

Theemile wrote:This has not been mentioned, and doesn't seem true - but....

Jonathan_S wrote:Anyway, circling back to the question of stopping.
The spider drive is described as grabbing ahold of the hyper wall. That at least raises the possibility that it could stop in some absolute sense - since presumably if you were able to grab points on all sides of the ship and pulled you'd be unable to move in any direction -- just hang suspected in your web of tension.

Though that possibility raises at least a couple of questions - neither of which we have the information to answer.

1) On an engineering level do any of the current spider drive systems have enough ability to alter their grab point to grab points immediately beside, or even angled behind their current position. If not, if they always have to grab points that are angled ahead of their current position then it would seem that the particular implementation of the drive would be unable to grab the hyper wall in such a way to know absolutely that the ship is stopped.

I don't think it matters. Grabbing the hyper wall and not letting go to grab a point on the wall further ahead should be sufficient. At some point no greater than the size of the ship the ship should come to a complete stop. It would be anchored to the wall.

Plus, the ship could face the wall and grab a hold of it while in the orientation of facing the wall. Akin to a human facing a wall and grabbing a hold of it instead of reaching out with our left hand to grab a hold of it.

Jonathan_S wrote:2) What relative movement might exist between the local hyper wall and the local star? (Or, if in hyper, between the next higher hyper wall an the n-space emergence point from there relative to the local star).

Intuitively there is an insignificant change of distance between the hyper wall and the star because of a phenomena called “frame dragging.” I touched on that in another thread. The sun is dragging everything in its local time frame with it as it orbits the milky way.

Do consider that when a spider drive latches onto the hyper wall, as far as I know, that in itself does not create acceleration; nor is the spider ship being dragged by the wall because the wall is moving. At least we haven't been told that information??? The ship must alternate grabbing and letting go to create the movement. Even though hyper walls are not walls as we usually think of walls, walls do not generally move. We also hear about ships “bouncing” off and or hitting up against the wall; which to me implies a wall that does not physically move. Although, it could also indicate that the wall does move because movement along with the direction of travel would be less dangerous for a ship. Akin to walking with a crowd of people in NY and bumping into the crowd while moving along with the crowd, as opposed to bumping into the crowd when moving against the crowd. I suggest a wall that is not moving.

But if “a” wall moved, then the highest band would contain a wall that is traveling much faster than the rest of the traffic. And hyper travel in a band that is against the flow of traffic (return trip) would be fatal if it hit up against movement that is much faster. Hitting up against a wall in a higher band traveling against the flow of traffic (against the grain) should be immediately fatal. Wouldn't that be like a head on collision?

Jonathan_S wrote:Being stopped relative to the local hyper wall doesn't seem especially helpful if the wall is, say, stationary relative to the center of the galaxy (and thus the local star is moving away from any fixed point on it by a couple hundred KPS -- the star's orbital velocity around the center of the Milky Way)

I don't think the wall is stationary relative to the center of the galaxy. Everything is part of the local frame of reference which is affected by and dragged by the local star at its orbital velocity. Again, see “frame dragging” in the wiki. As Earth revolves around the sun, the sun revolves around the Milky Way. The relationship between all players remain the same “within some constant,” IMO.

Jonathan_S wrote:Still, even the possibility of some way to ensure you were stopped dead relative to some spot in space (or hyper) is an interesting one.

Agreed. I have an idea about how it might be exploited. But first a little review about what we learned in school. We learned that the speed of light “C” is not just a measure of speed but also a measure of distance. C is the distance that light travels per unit of time. For instance, in a second.

If attacking Manticore, the MAN could travel by hyper at a constant speed in the higher band time after time again and measure the travel time to that waypoint. Let's say for the sake of argument the average ETA to the MBS is 3 hrs 20 minutes. Then, the coordinates of an anchored fleet should be 3 hrs 20 minutes from Darius. In case of drift, that drift should add / subtract the appropriate amount of time to the waypoint (“coordinates”). Therefore, a dispatch boat attempting to locate the fleet would travel at least 3 hrs 20 minutes. To cut the margin of error and the possibility of overflying the fleet the dispatch boat should slow down at about 3 hrs 15 minutes or so? Or at some time equal to the average drift at that distance traveled. I posit that the drift is constant, and a factor of distance traveled.

However, hyper lanes are wide enough that two fleets could pass each other and not know it. So how can a dispatch boat ensure that it will not fly by the anchored fleet? The solution comes from my college days on the few occasions where I had too much to drink. My freshman year I lived in a dorm that had twisting hallways at ninety degree angles. If I had too much to drink, how do I get back to my dorm room without missing it?

I placed my hand up against the wall and followed the twisting wall all the way back to my dorm room.

If a spider drive is attached to a hyper wall, then a dispatch boat can kill its drive minutes before the ETA and hug the wall all the way during the voyage. It will run into the anchored ship. Akin to traveling in the carpool lane all the way to your friend who has “broken down” in the carpool lane. Instead of several lanes over where he can be missed.

Note: If sails are only needed in grav waves??? Then can a spider ship raise sails in regular hyper anyway, to also serve as a beacon? IF a spider ship has sails which I do not think it has???

penny wrote:Note: If sails are only needed in grav waves??? Then can a spider ship raise sails in regular hyper anyway, to also serve as a beacon? IF a spider ship has sails which I do not think it has???

If the ship does not have sails, then it cannot use a wormhole. If a ship cannot move through a gravity wave, then it loses much (but not all) of the utility of hyper travel; for instance travel in a gravity wave provides all the energy a ship needs, totally free energy.

PS: I expect a ship could raise a sail as a beacon to where it is and help another ship could find it, if the incoming ship had not gone too far astray.

correcting misspelling

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penny wrote:

Jonathan_S wrote:Anyway, circling back to the question of stopping.
The spider drive is described as grabbing ahold of the hyper wall. That at least raises the possibility that it could stop in some absolute sense - since presumably if you were able to grab points on all sides of the ship and pulled you'd be unable to move in any direction -- just hang suspected in your web of tension.

Though that possibility raises at least a couple of questions - neither of which we have the information to answer.

1) On an engineering level do any of the current spider drive systems have enough ability to alter their grab point to grab points immediately beside, or even angled behind their current position. If not, if they always have to grab points that are angled ahead of their current position then it would seem that the particular implementation of the drive would be unable to grab the hyper wall in such a way to know absolutely that the ship is stopped.

I don't think it matters. Grabbing the hyper wall and not letting go to grab a point on the wall further ahead should be sufficient. At some point no greater than the size of the ship the ship should come to a complete stop. It would be anchored to the wall.

Plus, the ship could face the wall and grab a hold of it while in the orientation of facing the wall. Akin to a human facing a wall and grabbing a hold of it instead of reaching out with our left hand to grab a hold of it.

Except the wall isn't a physical object that exits within the current space/dimension; it's the barrier between two different spaces/dimensions. So there isn't any orientation that's 'towards' the wall -- the wall is everywhere and nowhere -- any direction a spider tractor shoots out from a ship it can grab the Alpha wall (assuming it was in normal space). And the ship body doesn't interact with the wall so I don't see how you could possibly hold yourself against it like a human holding themselves against a wall.

penny wrote:

Jonathan_S wrote:2) What relative movement might exist between the local hyper wall and the local star? (Or, if in hyper, between the next higher hyper wall an the n-space emergence point from there relative to the local star).

Intuitively there is an insignificant change of distance between the hyper wall and the star because of a phenomena called “frame dragging.” I touched on that in another thread. The sun is dragging everything in its local time frame with it as it orbits the milky way.

Do consider that when a spider drive latches onto the hyper wall, as far as I know, that in itself does not create acceleration; nor is the spider ship being dragged by the wall because the wall is moving. At least we haven't been told that information??? The ship must alternate grabbing and letting go to create the movement. Even though hyper walls are not walls as we usually think of walls, walls do not generally move. We also hear about ships “bouncing” off and or hitting up against the wall; which to me implies a wall that does not physically move. Although, it could also indicate that the wall does move because movement along with the direction of travel would be less dangerous for a ship. Akin to walking with a crowd of people in NY and bumping into the crowd while moving along with the crowd, as opposed to bumping into the crowd when moving against the crowd. I suggest a wall that is not moving.

Actually we hear about ships bouncing off the hyper limit. That's a different phenomenon.

Echoes of Honor wrote:A ship which attempted to translate out of hyper inside a star's hyper limit couldn't. As long as it made the attempt within the outer twenty percent of the hyper limit, all that happened was that it couldn't get into n-space. If it made the attempt any further in than that, however, Bad Things happened. Someone had once described the result as using a pulse cannon to fire soft-boiled eggs at a stone wall to see if they would bounce.

Hyper limits exist at specific distances from local gravitational bodies (the actual distance depending on the mass of the object). But the hyper wall exists everywhere, both inside and outside that limit -- that's how FTL comms, wedges, Warshaski sensors that can see wedges in near-realtime, and the Spider drive itself can all work inside the hyper limit as well as outside it. All require integration with the hyper wall.

So there's no particular reason to except frame dragging in this space/dimension to impact the hyper wall which is simply the barrier between spaces/dimensions. That said we also have zero evidence of whether the wall is fixed or not relative to the local star. It probably doesn't have significant velocity -- but a spider drive (which actually latches onto it) is the first thing we know of that might actually allow scientists to tell.
But if it's effectively stationary with respect to all local stars[1] then it must do something odd in the spaces between them because all stars aren't stationary with respect to each other.

But you're right that we haven't been told that simply latching onto the wall impart velocity. OTOH the spider drive is an overpowered tractor. It acts by pulling the ship towards the anchor point. So unless you specifically set things up so you have exactly opposing pulls (so the ship is held in tension between opposing sets of anchor points) it might be hard to disentangle motion imparted by the anchor moving (with respect to the local system) from motion imparted by the tractor pulling the ship towards the anchor.

That said, while we don't know and can't rule out the possibility that points on the hyper wall might move relative to a position in the spade/dimension 'below' them I do tend to think it unlikely.

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[1] or probably more accurately stationary with respect to the barycenter of local systems -- because, for example, it couldn't be stationary with respect to each star in a binary star system as they orbit each other.
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penny wrote:[snip]

Jonathan_S wrote:Still, even the possibility of some way to ensure you were stopped dead relative to some spot in space (or hyper) is an interesting one.

Agreed. I have an idea about how it might be exploited. But first a little review about what we learned in school. We learned that the speed of light “C” is not just a measure of speed but also a measure of distance. C is the distance that light travels per unit of time. For instance, in a second.

If attacking Manticore, the MAN could travel by hyper at a constant speed in the higher band time after time again and measure the travel time to that waypoint. Let's say for the sake of argument the average ETA to the MBS is 3 hrs 20 minutes. Then, the coordinates of an anchored fleet should be 3 hrs 20 minutes from Darius. In case of drift, that drift should add / subtract the appropriate amount of time to the waypoint (“coordinates”). Therefore, a dispatch boat attempting to locate the fleet would travel at least 3 hrs 20 minutes. To cut the margin of error and the possibility of overflying the fleet the dispatch boat should slow down at about 3 hrs 15 minutes or so? Or at some time equal to the average drift at that distance traveled. I posit that the drift is constant, and a factor of distance traveled.

More like 3 months than 3 hours. Even the Kappa band (as high as a streak drive can climb) tops out at a warship velocity of about 4,300 c. Just getting to Manticore from Sol through the Kappa bands would take you about 44 days.

And the hyperlog is more sophisticated than just dead reckoning by elapsed time. But your larger point is correct, if there is a known drift vector (velocity & direction) then by knowing how long the ships you're attempting to rendezvous with should have been waiting you can calculate where they should have drifted to and adjust your course to go there instead. (Or if unsure of the duration to to the original coordinates and then head down the drift vector until you've gone far enough they couldn't possibly have arrived early enough to drift past there). Your (or their) hyperlog might still have picked up enough positional error that you don't pass within sensor range[2] of them; but that issue doesn't change whether or not hyperspace has drift.
(Now if it has non-constant drift then that'd be a whole different problem

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[2] And as noted in previous posts one of the issues with an in-hyper rendezvous is that sensor range is so much lower; and much much lower still for ships using spider drives (which are invisible to the much longer ranged grav sensors). Though your point that they might be able to use sails (if they have them) as a "here I am" signal is a good one.

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penny wrote:However, hyper lanes are wide enough that two fleets could pass each other and not know it. So how can a dispatch boat ensure that it will not fly by the anchored fleet? The solution comes from my college days on the few occasions where I had too much to drink. My freshman year I lived in a dorm that had twisting hallways at ninety degree angles. If I had too much to drink, how do I get back to my dorm room without missing it?

I placed my hand up against the wall and followed the twisting wall all the way back to my dorm room.

If a spider drive is attached to a hyper wall, then a dispatch boat can kill its drive minutes before the ETA and hug the wall all the way during the voyage. It will run into the anchored ship. Akin to traveling in the carpool lane all the way to your friend who has “broken down” in the carpool lane. Instead of several lanes over where he can be missed.

Note: If sails are only needed in grav waves??? Then can a spider ship raise sails in regular hyper anyway, to also serve as a beacon? IF a spider ship has sails which I do not think it has???

Again, hyper walls are everywhere. The only divide one layer of hyperspace from another. They don't restrict a ship's 3 dimensional movement within the layer of hyperspace. So you can't put your hand against one and follow it home.

Also Honorverse hyperspace is just a more compressed (and high background EM noise) version of normal space. There's aren't hyper lanes. The only thing like that is the normal space transit lanes near a wormhole terminus (which seem to be around 40-50,000 km wide) or grav waves in hyper (which can be multiple lightyears wide). But you don't have to follow grav waves in hyper -- it's perfectly possibly to cut straight across the rifts between them (and probably 90+% of hyperspace is rifts, not waves). But, again, your point that it's quite possibly to sail past an entire other fleet without either being able to see the other is quite true. Hyperspace is vast, and sensor ranges are painfully short (compared to normal space)

But assuming a spider ship mounts sails (something RFC hasn't confirmed; despite very strongly implying they were capable of using wormholes) there's nothing stopping a ship from raising its sail wherever it wants. It won't provide propulsion unless its in a grav wave or one of the transit lanes around a wormhole terminus, but it'll still be a big visible grav signature. (And, in fact, if a ship is departing from a system that lies without a grav wave the ship must transition from wedge to sails before using its hyper generator to crack the Alpha wall and enter hyper. It'd just be coasting with sail up in the (likely brief) interval between raising sail and translating into hyper; but it needs the sails already up to stabilize it as it'll appear in hyper already in the middle of the grav wave that the system lies within.

In one of the books, dunno which one, it talked about an RMN ship -- that has removed the safety interlocks IINM -- that bounced off the next higher wall. I am sure about that. So, whether the wall is a physical construct or not, for all intents and purposes, it acts like one.

That also implies that the walls are not "all around" in hyper. In n-space the wall is everywhere, I agree. But the definition lists walls as the "area" between n-space and hyperspace; a physical boundary.

penny wrote:In one of the books, dunno which one, it talked about an RMN ship -- that has removed the safety interlocks IINM -- that bounced off the next higher wall. I am sure about that. So, whether the wall is a physical construct or not, for all intents and purposes, it acts like one.

That also implies that the walls are not "all around" in hyper. In n-space the wall is everywhere, I agree. But the definition lists walls as the "area" between n-space and hyperspace; a physical boundary.

You are probably thinking of The Honor of the Queen, when Commander Truman bounced off the Iota wall in her haste to get help for Honor fighting the bigger PRH ship.

But that does NOT mean that walls are NOT "all around" in hyper, the higher walls are the barriers between hyper-bands; which are everywhere, the same as the wall between normal space and the Alpha band. How could Truman bounce off the Iota wall, if it was not there?

tlb wrote:You are probably thinking of The Honor of the Queen, when Commander Truman bounced off the Iota wall in her haste to get help for Honor fighting the bigger PRH ship.

But that does NOT mean that walls are NOT "all around" in hyper, the higher walls are the barriers between hyper-bands; which are everywhere, the same as the wall between normal space and the Alpha band. How could Truman bounce off the Iota wall, if it was not there?

Yep, that's be the one

The Honor of the Queen wrote:“Charlie, this is the Captain. You people ready for translation?”
“Yes, Ma’am. About the only parts of this ship I can vouch for are her propulsive systems, Skip.”
“Good.” Truman never took her eyes from the departing dots of Honor’s other ships. “I’m glad to hear that, Charlie, because I want you to take the hyper generator safety interlocks off line.”
There was a moment of silence, then Hackmore cleared his throat.
“Are you sure about that, Captain?”
“Never surer.”
“Skipper, I know I said propulsion’s in good shape, but we took a lot of hits. I can’t guarantee there’s not damage I haven’t found yet.”
“I know, Charlie.”
“But if you take us that high and we lose it, or pick up a harmonic-”
“I know, Charlie,” Truman said even more firmly. “And I also know we’ve got all the squadron’s wounded with us. But if you kill the interlocks, we can cut twenty-five, thirty hours—maybe even a little more—off our time.”
“Figure all that out on your own, did you?”
“I used to be a pretty fair astrogator, and I can still crunch numbers when I have to. So open up your little toolbox and go to work.”
[snip]
“I noticed,” he chose his words with care, “that you made excellent time from Yeltsin’s Star, Commander.”
“Yes, Sir.” Truman’s voice was uninflected, and Alexander smiled.
“That wasn’t a trap, Commander. On the other hand, I know perfectly well you didn’t cut thirty hours off the old passage record without playing games with your hyper generator.”
Alice Truman looked at him for several silent seconds. Lord Alexander—no, he was the Earl of White Haven, since his father’s death—was known for a certain willingness to ignore The Book when it got in his way, and there was an almost conspiratorial gleam under the worry in his eyes.
“Well, yes, My Lord,” she admitted.
“How high did you take her, Commander?”
“Too high. We bounced off the iota wall a day out of Yeltsin.”
Despite himself, Alexander flinched. Dear God, she must have taken out all the interlocks. No ship had ever crossed into the iota bands and survived—no one even knew if a ship could survive there.

So very clearly the Iota wall (and by extention any hyper wall) is something you can only run into by using your hyper generator; meaning it's not something physically in your way as you move through 3-dimensional space.


And there is a reason it's call the Alpha bands (or the Theta bands) - there are subbands that we hardly ever talk about - as all we have is the singular speed number listed in the 'Speed by Hyper Band' table for each set of bands; which appears to be the mid-band velocity (or average velocity) possible in that set of bands.

For example, also in HotQ, we get

The Honor of the Queen wrote:At the moment, for example, Honor’s convoy was cruising along in the mid-delta bands, which translated their .5 C true velocity into an effective velocity of just over a thousand times light-speed. At that rate, the thirty-one light-year voyage to Yeltsin’s Star would require ten days—just under nine, by their shipboard clocks. Left to herself, Fearless could have made the same crossing in less than four.

And if we check the chart, it says a merchantman has an effective times c of 1089; which is pretty close the "just over a thousand".

Presumably, if you push into one of the higher sub-bands you get a bit more effective times c without actually cracking the next hyper wall -- and that appears to be what Alice and her chief engineer tried, pushing into the highest possible sub-band within the Theta bands to eke out any bit of time saving they could, while avoiding translating through the Iota wall. And with the safety interlocks off (that presumably limit how high a sub-band you can slip into) they pushed so high that they nearly did accidently transition through the Iota wall; something that would have been fatal had they not somehow aborted/canceled/avoided it.

As an aside, something seems hinky with the time savings RFC used, where Alice saved 30 hours off the old passage record.

Either he massively fumbled the numbers of else the old passage record was really slow.

Logically there's no way the highest sub-band of Theta gives you a higher 'apparent times c' than the one the chart lists have for the Iota bands[1]. And he says Fearless could have made the (31 LY) passage from Yeltsin's Star to Manticore in less than 4 days. The chart backs that up, if we discount accelerating time at the specified 3000c for the Theta bands the transit would take 3.77 days (90.52 hours).

Now Apollo could slightly out accelerate Fearless and Alice probably pushed the compensator safety margin as well to improve that. But that < 4 days number for Fearless just highlights that acceleration time couldn't have been that big a % of the transit time; discounting acceleration it'd take a warship 90.52 hours in the Theta bands, and 4 days is only 96 hours -- so there's only 5.52 hours margin to play with for any acceleration or other delays.

So she's definitely not shaving 30 hours off of the theoretical time Fearless could do the trip in -- even if she'd been able to enter the Iota bands.

A warship in the Iota bands would take 75.43 hours to cover 31 lightyears; just 15 hours less than the chart gives for one in the Theta bands. And since without entering the Iota bands she clearly couldn't get her effective times c up that high. So even using the mid-Iota bands & accelerating instantly (both impossible for Apollo) she couldn't have shaved 30 hours off of Fearless's theoretical transit time.

Leading me back to my point that either the previous transit record was substantially (like 25%) slower than what any RMN warship could theoretically do with normal safety margins or RFC fumbled the math.

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[1] Well technically it only lists the 'Velocity Multiplier' for the Iota bands. But the warship 'Effective Times C' is just 'Velocity Multiplier' * 0.6; and the Merchantman 'Effective Times C' is just 'Velocity Multiplier' * 0.5 (because a warship's particle shielding can take 0.6c within hyper while a merchantman's can only take 0.5c)
So we can trivially calculate that if it could access the Iota bands a warship's number would be 3600 and a merchantman's would be 3000