Sea Ships relative speeds

[IckyATLAS]

In my quest to the perfect convoy here is another approach to the problem.

 

To have a convoy keep its structure and this means distances between ships (remember in WWII Atlantic convoys this was around 700 meters spacing), either you build a very complicated logic to steer each boat and change the speeds to keep the distances for each waypoint segment, (believe me it is a very very complex and heavy logic which increases by multiples for each additional boat and again for each additional waypoint, but it can be done for sake of the beauty of the thing) or you choose a more simple approach based at ordering the boat speeds and composition so that on certain amount of time compatible with your mission the convoy will hold. In any case you have to know that if a convoy where each ship has its own waypoints and if the ships are one behind the other, and if one ship gets damaged and stops (not sinked) the one coming behind will collide and both will be destroyed. So you may space laterally in a variable Z pattern your ships so that they will not bump in each other and the one behind will just pass and overtake the one in front.

 

The main problem is that in this game if you give a target speed of 15 kph to a cargo ship and a 15 kph target speed to a torpedoboat, they will not go at the same speed. That's a pity as this game is very precise, and it would make sense that 15 kph is the same for everybody give and take +/- 0.5 kph.

 

So the test here happens on 1500 mt long stretch from start and all ships have a 15 kph target speed. Time is beautiful, no wind, blue sky, sea state is zero.

The Destroyer crossed the line first at 336 seconds from start. This is an average of 16 kph.

 

Here is the relative classification with timings and speeds:

 

Destroyer at :                 336 seconds, average speed 16.00 kph

Torpedoboat 38 at :      360 seconds, average speed 15.00 kph

Torpedoboat G5 at:      361 seconds, average speed  14.96 kph

Fastboat 1124 at :        368 seconds, average speed  14.67 kph

Subsh10 at :                   373 seconds, average speed  14.47 kph

Sub2b at :                       378 seconds, average speed  14.28 kph

Large Cargo Ship at:     381 seconds, average speed  14.17 kph

Landing boat at :           384 seconds, average speed  14.06 kph

Large Tanker Ship at:   385 seconds, average speed  14.02 kph

 

Finally between the fastest and the slowest boat there are 2 kph difference. This means that in one hour the distance will have stretched by 2000 mt. 

 

Next to come when Sea State is 6 check what happens. I have also set the windspeed at 20 mt/sec full front or at 270 degrees (ships go at 90 degree direction). The worst conditions.

Waves in this game are not dependent to the wind direction and are moving in the 180 degrees direction it seems. So they hit laterally the boats and not frontally.

There are some differences in ranking:

 

Destroyer first

Torpedoboat 38 at :   24 sec

Torpedoboat G5 at :  25 sec

 

Fastboat 1124 and Subsh10 at :   42 seconds

We see that Fastboat has really slowed a bit and has been catched by Subsh10 that slowed too but less.

 

Sub2b and Cargo are at : 49 seconds

Both have slowed but not by the same amount and have catch each other

 

Tanker stands at : 53 seconds

It has also slowed

 

and finally the last is the Landboat which stands at 111 seconds. He is the most affected by sea and wind conditions.

 

Conclusion the speed differential between the Destroyer and the Landboat is of   4 kph. This is the double than the differential in perfect calm conditions.

This is perfectly normal. The destroyer has a profile that allows to penetrate the waves much better and has more power against wind. So it is logical that the Landboat gets the most affected.

In reality the difference should be much much bigger.  And what happens when waves are oriented against the ships?

 

With the same conditions but this time wind and waves are in the same direction, there is no difference at least for the destroyer which will still have the same average speed as with calm conditions.

But this time the Landboat cuts the line together with the tankers. It went somewhat much faster on this run. I don't think the waves make a difference but maybe there is some randomness on ship speeds like the Landboat to simulate the load. It does not seem to be the case with Cargos and Tankers which perform in a predictable way.

 

With all this data in your hands, it is time now for you to play with a build superb convoys in the Black sea and in rough seas. In the Black Sea there can be terrible storms.

 

 

 

 

 

 

 

 

Edited December 31, 2020 by IckyATLAS

[DN308]

Outstanding job.

thanks for that

[No_85_Gramps]

Thanks for this info Icky! Trying to work out some convoy plans with your convoy groups and this is great info! Thank you for taking the time to work this out, and also for the convoy groups.

[IckyATLAS]

I would just add a small comment to my calculations above. After some updates and the major update where there has been a change of format I cannot guarantee that there has been no impact. In theory there should be no impact but who knows. However there may be an impact after BON is released because I see that multiple different ships are being designed and it may be that the way ships behave in the sea could be improved and as a consequence have a new reviewed ship motion simulation. At the moment the turning of ships is really not well simulated and turns with waypoints are not well simulated and it has to do with trajectory interpolation.  Modeling a large convoy with many columns and doing turns is a nightmare to program with the tools we have in the ME.

 

There is also a problem with vehicles (they do not skid ion the ground like in water) that make 90 degree turns again very badly simulated and nearly impossible to do properly. This is why having a column of vehicles moving in a city with narrow streets and with 90 degree turns does not work well and often vehicles collide with the buildings. There is a strategy of collision avoidance between vehicles when one is incapacitated and the one following makes a turn to avoid it. There is no such strategy with ships and ships will collide straight on. If in a ship column one ship stops because he is damaged the one coming behind will collide into it.

 

Hope these things will be improved in the future. After all the title of this game is now "Great Battles" which means not only planes have to be very well simulated but the rest of the battle scene too. ? 

 

[No_85_Gramps]

4 minutes ago, IckyATLAS said:

 

Hope these things will be improved in the future. After all the title of this game is now "Great Battles" which means not only planes have to be very well simulated but the rest of the battle scene too. ? 

 

I agree with that. Some time back I noticed the problem with vehicles in the cities, quite funny to watch though.