Water jets are too slow

[motorhorn]

I've tried and tried to get water jets (propultion) to work but they are just so slow. I don't know if I just need a massive engine/water pump but they just seem to be not worth the effort. If anyone knows how to make them go fast, please tell me. Thanks

[D3S3RT]

Try to connect Waterpumps in serial. Fluid out from pump 1 goes to fluid in of fluid pump 2 and so on... Last fluid out goes to the Waterjet. 6 Large Pumps together with 1 small engine is enough for most small ships i built so far.

[Ra-Ra-Rasputin]

I have to disagree, based on this is 15% throttle:

https://i.imgur.com/22Xah8Z.png

and this is 40% throttle:

https://i.imgur.com/kxfFsAV.png

Those are in meters / second by the way.

https://i.imgur.com/Y3CvFUy.png

Powered by these

https://i.imgur.com/Wbp9el5.png


Timicro has been in the earlier iteration of this vessel, so he can definitely verify the claim.

This is the distance covered in one minute, including the startup sequence. https://i.imgur.com/59bR0td.png

[Ra-Ra-Rasputin]

To give an actual answer:

Basically, the way the waterjets work is that they need high speed to get high speed. Partial clutch engagement does wonders here, as does something that takes care of the lower speed (such as a standard propeller). The faster their input sucks up water, the faster they can go.

They also demand a pretty high RPS input, so you don't often want to fully engage clutch to get the highest speed out of them.

[motorhorn]

I tried some more and am still having trouble. Is there a good tutorial video?

[Ra-Ra-Rasputin]

I sadly have no idea about tutorial videos. Let me mock up a small boat quick-ish. Give me approx half an hour.

[Ra-Ra-Rasputin]

Here's a fun toy for you to play with
https://steamcommunity.com/sharedfiles/filedetails/?id=2069423838

Don't push the clutch on to full and you'll be fine. With a proper balance system tweaking that vertical trim it should zoom about at 80-100 m/s right now it gets very unstable at around 50 and it just gets worse from there.

[motorhorn]

ok thanks very much, I'll check it out

[motorhorn]

Originally posted by Ra-Ra-Rasputin:

Here's a fun toy for you to play with
https://steamcommunity.com/sharedfiles/filedetails/?id=2069423838

Don't push the clutch on to full and you'll be fine. With a proper balance system tweaking that vertical trim it should zoom about at 80-100 m/s right now it gets very unstable at around 50 and it just gets worse from there.

This was very useful, I am going to try to build a boat similar to this a bit later. Thank you so much.

P.S. Can I ask what all of the rudders are for since some of them don't seem to be connected to anything? thanks.

[Ra-Ra-Rasputin]

They're there for hydrodynamic balance. The rudders are very small, and they change the profile of the craft significally even when they're sitting there seemingly doing nothing.
They resist motion against the flat end strongly, and they become even more powerful when the speed increases.
Try making a flat rectangle for instance in the creator, and drop it flat-side down into the dock. Then slap rudder fins pointing sideways on every corner and do it again, you'll see a significant difference.

The small and medium control fins work better in most cases when you have high speeds like planes or need smaller adjustments, but the rudder fins are capable of producing very strong adjustments with less motion. The back pair of rudder fins are there solely to keep roll in check, and despite the PID not reacting to speed input in any way, since it is "lazy" at lower speeds it works fine at higher speeds due to that property.

[motorhorn]

https://steamcommunity.com/sharedfiles/filedetails/?id=2070035006

I tried and failed again: if the clutch is released too much the rps dies and it can't go faster than ~6.5 mps. I tried changing how high the jet is and it still doesn't work. Can you have a look and see if you can find what's wrong with it? Thanks.
btw I think I forgot to change the lables and clutch is just W and S

[Ra-Ra-Rasputin]

Sure i can, though a little bit later. Generally you want to be careful with how much the clutch engages for these, and it requires quite a bit of fiddling.