For captains / feedback kit / draft v0.1

Tell us where the boat is wrong.

This sheet is for working ATB captains and mates who have agreed to test BERTH. The handling was built from a physics model and tuned by scripted runs and by one director who is not a captain. No ATB captain has driven it yet. You are the first check.

Tested by (initials or nickname)

Date

Build played (see the game page footer)

1. What we want from you

Two things.

Does it feel like the job? When you do what you would do on the boat, does the unit do what the boat does? Where it does not, what is wrong: too fast, too slow, too strong, too weak, the wrong direction?
Does it reward the right technique? If something a real crew would never do works in the game, or something they always do fails, that is the finding we most need.

We are not asking whether it is fun or pretty. We are not asking you to find bugs in the menus. If you see one, note it, but the handling is the point.

How to run it. The game is a browser page. Press PLAY on the BERTH page, or double-click PLAY.cmd in the folder you were given, and it opens in Chrome. Nothing installs, nothing goes online, and your results are saved only in your browser. Keyboard is best; the mouse works for everything too. F1 shows the controls at any time.

2. Before you start: what is deliberately simplified

Some things are known departures from real behaviour. Please do not spend your time reporting these; we know, and some are deliberate. If one of them stops you doing a manoeuvre the right way, that we do want to hear.

Ignore this	Why it is that way
The unit is fictional. Barge 216 x 24 m, tug 40 x 15 m, 236 m overall, loaded 45,000 t. Bow thruster 150 kN.	It is a class, not a vessel. No real vessel, company or figure is used.
Momentum is compressed about 3x by default. The unit gains and loses way about three times faster than real. Turn rate and top speed are physical.	So a berth takes 4 to 8 minutes instead of 15 to 25. Press G in the menu to switch to Realistic momentum and judge the real timing; both are saved separately. Please do at least one berth each way.
Fenders catch you. Landing on the fenders under 0.25 m/s (Easy) or 0.15 m/s (other tiers) is clean. The dock is meant to be touched.	Design pillar: controlled contact is the goal.
Taking a line is instant. Press E when the prompt says READY and the line is on. No heaving line, no time for the crew.	The capture rules (reach 10 m, point speed 0.4 m/s, angle 30 degrees) stand in for the crew's judgement.
The line leads are fixed. Lines go to the nearest bitt (a breast lead); on Easy the forward line takes a spring lead 25 m aft. You cannot choose a bitt.	Simplification. Tell us if the lead you would choose is never offered.
Winch figures are game values. Brake 300 kN, constant tension 20 kN, heave limit 120 kN. The line never parts.	Not real ratings.
Once secured, the unit freezes. No wind or surge acts on a moored unit.	Simplification.
The moored ships are as hard as the quay and have no fenders of their own.	Simplification; touching them at any speed over 0.05 m/s is damage.
Shallows slow you and rub; they do not ground you.	There is no depth model.
No current, no ice, no shallow-water effect, no bank suction, no waves.	Not in the physics yet. Wind is the only environment.
No prop walk. The single-screw tug backs straight.	Not in the physics yet.
No reverse flow over the rudder. Going astern, the rudder does nothing on SIMPLE. On TWIN SCREW and VECTWIN the washed rudder of an ahead prop still works.	Known.
The tug and barge are rigid. No articulation, no pin movement.	Simplification.
Art and sound are placeholders in places. The console is a design, not a specific bridge.	Not what we are testing.

3. What to try, in order

Allow about an hour. The times are a guide.

3.1

Practice 10 minutes

Main menu, PRACTICE, pick a tug type, then the drills: open water, spin in place, walk sideways, stop from 3 kn, spring-line swing-in. Nothing is recorded here.

Try all three tug types on spin and walk. Tell us whether the differences between SIMPLE, TWIN SCREW and VECTWIN are the differences you know.
On stop from 3 kn, note how far the loaded unit runs with full astern. Then switch to Realistic momentum (G) and do it again.

3.2

Easy berth, your own way 10 minutes

Pick the tug you know best. EASY, the tight berth: a moored ship astern, a shallow corner ahead, no wind. Ignore the hints the first time. Dock it the way you would.

Did the game let you do it your way?
Did the E prompt offer the line you wanted, when you wanted it?

3.3

Easy berth, the taught way 5 minutes

Read the method card on the briefing screen (bow on the fenders, forward line on a spring lead, slow ahead with the rudder away from the dock, let the stern walk in, touch ahead at the end). Do it that way.

Is this a technique you use or have seen used?
The stern walks in on about 10 percent ahead. Is that about the power you would use, or too little, or too much?
The forward line will sit near the brake limit for part of the swing and may pay out a metre or two. Is that what the line does on the boat?

3.4

Medium: wind 10 minutes

MEDIUM is a steady 12 kn off the berth, and you call the lines (hold H to heave, L to let go the line fighting you).

Does the unit set off the berth the way a loaded unit does in 12 kn?
Does the crew do roughly what your deck crew would do on those orders?

3.5

Hard: gusts, your call on the lines 10 minutes

HARD is 20 kn gusting to 35 kn off the berth, full manual lines (pick a line with 1, 2 or 3, then L let go, K slack, H heave, B hold).

Where does it go wrong first? Approach, the first line, the swing, or the landing?
A known finding: on VECTWIN, if you centre the rudder before the stern is inside line reach, the stern blows back out. Did you see that, and is it right?

3.6

Realistic momentum 10 minutes

Press G in the menu to turn Realistic momentum ON. Repeat 3.3 and 3.4.

Which setting feels like the boat? We think Realistic is right and compressed is a convenience. Tell us if you disagree.
Easy with Realistic momentum will bottom a fender if you arrive with the bow still closing at 0.4 m/s and yawing in. Is that fair?

3.7

Mastery optional, 5 minutes

Empty barge, no bow thruster, 20 gusting 35 off the berth. The tier select says UNVERIFIED: no scripted driver has ever finished it. Try it once. If you finish it clean, we want the replay.

Is this a day you would sail on, or a day you would wait out?

3.8

Things to try that are not on the cards

Kick ahead while still making sternway. We suspect the model gives roughly twice the side force it should in that moment. Tell us if the stern jumps.
Back the unit onto the berth instead of coming in bow first.
Hold the thruster at full while at 3 to 4 kn. The thruster fades to nothing at 4 kn on an assumed curve. Say when it stops doing anything on the boat.
Come in too fast on purpose and see what the fender and damage messages say. Are the speeds where damage starts (0.15 m/s on fenders, 0.30 hard landing on Medium and above) in the right place?

4. Question sheet

Answer what you can. Numbers are welcome but a word is fine. Circle or tick an option, or use "right", "too much", "too little", "wrong way" if that is all it needs.

About you

Years on ATBs or tugs: Twin screw, single screw, Z-drive, other:
Tug type you tested most. SIMPLETWIN SCREWVECTWIN
Momentum setting you preferred. compressedRealistic

Engine and rudder

Engine answers the lever in about 1.3 s with no shaft lag. righttoo fasttoo slow
Rudder authority fades to nothing at zero way, and a centred rudder under way holds heading. rightwrong
Prop wash over the rudder at low speed, to kick the stern. enoughtoo muchtoo little
Kick ahead while making sternway (3.8): the stern response was righttoo strongtoo weak

Bow thruster

150 kN on a 236 m loaded unit. enoughtoo muchtoo little
Pitch travel full to full in 10 s. righttoo fasttoo slow
It fades out between 1 and 4 kn. rightfades too earlyshould work at higher speed

Lines and crew

The line you wanted was offered when you wanted it. alwaysusuallyrarely
The spring lead (Easy forward line) is a lead you would use. yesnodepends
The brake paying out at 300 kN and the line never parting. fine for a gamemisleading
Constant tension 20 kN as the default winch mode. rightyou would use slack-onlyother
The deck crew on Easy (automatic) and Medium (you call it, they pick the winch). about righttoo helpfultoo dumb
Taking the aft line first: did the game let you? Did it make sense?

Fenders, contact, damage

Clean landing under 0.15 m/s, hard landing at 0.30 m/s, damage above. righttoo stricttoo loose
Did any contact that should have counted go uncounted, or the reverse?
Touching the moored ship at 0.05 m/s counts as damage. fairunfair

Wind

12 kn steady on a loaded unit. felt righttoo much settoo little
20 gusting 35. Did the gusts come in a believable pattern? felt righttoo muchtoo little
Empty barge in wind (Mastery). believablenot

The whole

Is this how you would do it? If no, what is the first thing you would change? yesmostlyno
Did anything work in the game that you would never do on the boat?
Did anything you always do on the boat fail in the game?
What berth, condition or manoeuvre would you want next?
Would you let a new mate learn on this? yeswith caveatsno

5. How to send it back

Fill the sheet: a text file, a photo of paper, a voice note, anything.
If you get a result you think is wrong, open the pause menu and note the attempt time and tier, then tell us what you did. Each attempt records its inputs and gust seed, so we can replay it exactly. You can also export the replay from the REPLAYS screen and send the file.
If you finish Mastery clean, say so and we will come and get the replay.
Note the build id from the footer of the game page so we know which version you drove.
Nothing you say will be quoted with your name or your boat's name in any document or in the game.

BERTH / captain feedback kit v0.1 / Build a20925a / 2026-10-01 / files d0ea5e81