Only get ~10 speed with 4 diesel engines and a small propeller?

[Lymark]

I've been building a diesel powered submarine and running into this issue, where I'm stuck at around 7~10 speed max no matter what. I've tried all gearbox settings and bigger propellers.

I thought maybe my sub is too heavy, so I built a bare bone boat that was barely enough to fit 4 diesels(200k ones), a small prop and a 3:1 gearbox, same result. The boat gets to 11 speed, 4 Engine 4RPS, ~40 Prop RPS and 65 torque. (Before releasing the clutch, my engines have reached 55RPS, which seems to be the max even though RPS limiter is set to max.)

I'm no expert in engineering, could someone please enlighten me what the issue could possibly be? Thanks!

[Jackgunz]

reverse your gearbox so that the arrows point toward the engine, that you will get 3 rotations out of the prop for each one rotation of the engine. 4 large diesels can power one large prop easily in my opinion.
I have a smallish boat with 4 large diesels pushing 3 azimuth thrusters; with a backwards gearbox, it averages 17.5m/s to 18m/s at full power. (although the engines are only cranking at 8.7rps, the props turn 3 times faster than the engine) if i put the gearbox in a "normal" orientation, it barely makes 8m/s at full power, and the props trun 3 times slower than the engines.

[[deleted]]

https://steamcommunity.com/sharedfiles/filedetails/?id=1526611553
The current meta is adding more screws or limiting rps of engine for a single screw. Check my boat it uses 1 small engine per small prop ang reaches 18 m/s on 24.67 trq.

Screw have its own rps and it doesn't want to go beyond apprx. 20. Adding more screws adds at best several m/s, its non linear proportion. Thanks to Teamkiller for science.

[Huh. That's suck.]

I have a big ship with 4 diesel engine and giant propeller, Its too slow! I tried add more engine and propeller (1 giant propeller per 1 diesel engine), It doesnt make more fast, but make the ship more heavy. anyone can help? I can give my prototype ferry ship if you want too.

[ghettodexter]

Ive noticed many items have a max RPS but depend on other items with different MAX rps... this causes confusion in builds. There needs to be more technical information given in the discription of parts.

[Lymark]

Originally posted by JackGunz:

reverse your gearbox so that the arrows point toward the engine, that you will get 3 rotations out of the prop for each one rotation of the engine. 4 large diesels can power one large prop easily in my opinion.

Sorry, I should have stated that clearly, but yes, my gearboxes are pointing toward the engine with a 1:3 setting.

Here's two screenshoots with my barebore boat. Either a small or large prop, It's still roughly the same top speed. It's a 1:3 ratio setup too.
https://imgur.com/a/yHVqgLM

Originally posted by konakona:

Check my boat it uses 1 small engine per small prop ang reaches 18 m/s on 24.67 trq.
Screw have its own rps and it doesn't want to go beyond apprx. 20. Adding more screws adds at best several m/s, its non linear proportion. Thanks to Teamkiller for science.

After adding 4 props to each engine individually , my boat now goes flying with a 30m/s speed! So, It does seem like a single prop is bottlenecking my power output.

Btw, tried downloading your boat, but it doesn't show up in my game.

Originally posted by Papa Stalin:

I have a big ship with 4 diesel engine and giant propeller, Its too slow! I tried add more engine and propeller (1 giant propeller per 1 diesel engine), It doesnt make more fast, but make the ship more heavy. anyone can help? I can give my prototype ferry ship if you want too.

Try powering your props individually instead of 'shared powering'. So, if you get 4 diesels, then add 4 propellers that feed off from a single engine each.

[Lymark]

Edit: I just jumped back to my sub, and I'm still stuck at ~10 speed with 4 props that are powered by 4 diesels. I guess It's just too huge and heavy to be powered by only 4 props? My sub has the length of the entire limit in build mode.

[Lymark]

Originally posted by konakona:

Check gearboxes on the sub. Btw gearboxes past 0.4.3x and before are different and works a bit different, you might need to replace 'em.

3:1 is the best(only 15RPS tho), adding a 2nd gearbox also gains me another 0.5 m/s somehow.

I've also just tried doing a 6x diesels+ x6 props setup, same speed. Actually, I just made it worse because now some of my props are having different RPS. Think I'm just gonna suck that 10m/s up and call it a day.

Edit: After further testing and a proper 6 engs/props set up, I'm able to gain another 2m/s(Total of 12m/s). So, It seems to me that my sub is just way too heavy.

[Nocturnalist]

Its been that way for while now, they either nerfed the props output or the engines but either way 14 to 21 will be around your max. I have starter boat I created with 6 engines and 6 props and at 100 throttle / Clutch I get 21 knots.

So I haven't touched the game since, the Devs claim engines are running right, well yea were not discussing thier operational status, we are questioning either the props output or the motors, its like having a weedeater engine on your boat.

Mattar fact I have a 14ft. boat (in real life) and I have a tiny 10hp 4stroke on it and it goes about 15knots, So I don't know where they get this logic.

(unless we are dealing with 10hp motors)

[Nocturnalist]

Originally posted by konakona:

Default measure in game is m/s. 1 knot = 0.514 m/s.

Thats cool and all but has no bearing on what we are talking about, the point is 8 engines and 8 props will push u about 21knots, thats stupid. Specially on a starter boat that doesn't even weigh that much.

People will argue its gearbox blah blah blah, thats why u can go on the work shop and you won't find one speed boat that goes over 21 to 30 knots that isn't using logic or some way to jerry rig it. Yeah that make great logic must be us.

[Nocturnalist]

Originally posted by konakona:

Originally posted by Nocturnalist:

Thats cool and all but has no bearing on what we are talking about, the point is 8 engines and 8 props will push u about 21knots, thats stupid. Specially on a starter boat that doesn't even weigh that much.

Then add 3:1 inverted gearbox. I just though you miscalculated actuall speeds. 19m/s is definitely possible on weakest setup, that's about 40 knots.

Ok my bad, no one ever in marine industry will ever refer to m/s, so I figured the speed was in knots. so I can get boat to 19 to 30 m/s and everyone thinks thats exceptable?

And on top that I just explained I have 14ft that does 10mph ( maybe didn't make that clear) and so I can't make my boat in game go as fast as a 14ft with 10hp motor in real life.

Let me add this cause people will get stuck in details, I know theres a difference between m/s and mph, but its not that great, boats should be able to go faster.

[Huh. That's suck.]

Originally posted by Lymark:

Try powering your props individually instead of 'shared powering'. So, if you get 4 diesels, then add 4 propellers that feed off from a single engine each.

so, 1 engine 4 giant propeller? and how about the gearbox setting? Sorry, I dont understand about gearbox

[Nocturnalist]

Originally posted by Papa Stalin:

Originally posted by Lymark:

Try powering your props individually instead of 'shared powering'. So, if you get 4 diesels, then add 4 propellers that feed off from a single engine each.

so, 1 engine 4 giant propeller? and how about the gearbox setting? Sorry, I dont understand about gearbox

No he telling you, if you use 4 motors have them all have thier own drive shaft (pipe) that goes to 4 props individually, don't forget gearbox (set to 1:3) and clutch, but, it won't matter your be stuck at real slow speed.

[VlamBallas]

Use a Jet Engine!
These can can comfortably do 150+ RPS (with no load attached) = LOTS OF POWER!
No need for fancy PID + logic circuits.
(I would recommend a more advanced clutch-throttle control system though!)

Engine:
* Intake -> Compressor -> Combustion -> Turbine

Pipes:
* Turbine Output
** Clutch
*** Gearbox for Reverse
**** OPTIONAL Gearbox
***** 2 or more Small Propellers
More Small Props = More Speed

Logic:
* Engine ON/OFF -> Toggle Button
** Engine Throttle -> Helm W+S
** Clutch Pressure -> Helm W+S

* Clamp the throttle value to something like 0.1 if the engine keeps stalling out at idle.
** The OPTIONAL 2/3:1 Gearbox does not increase top speed, but it does lower
the egine RPS, reducing fuel drain significantly.

I get speeds of about 35 ~ 40, on a medium-ish speedboat using this setup...

Cons:
* A jet engine is noisy AF.
** Engine startup is a pain in the ass, as you have to wait for the engine to spool up,
Fuel combustion only kicks in once the RPS is high enough.
Hit the gas once you hear the BOOM!
*** Keeping the Engines Intake dry can be challenging in rough seas

[Aiglefins]

Use thermal engines to generate electricity and electric motors for propellers if you can.

[HoboCop]

Originally posted by VlamBallas:

** Engine startup is a pain in the ass, as you have to wait for the engine to spool up,
Fuel combustion only kicks in once the RPS is high enough.
Hit the gas once you hear the BOOM!

Na, I've made a turbine powered helicopter that starts instantly! How? Easy - I used 2 small motors to turn the turbine instead of the "starter", I then have logic that turns those motors off and disengages the "starter clutch" as soon as the RPS is over a given value. That combined with logic to keep a given RPS, they are dead simple to use.

I'm also on with building a hybrid rescue boat too (RNLI style) which contains 2 "aircraft" engines and a single small electric motor and it'll do 28/29 knots (NOT m/s) and the battery also remains charged using several small generators per motor and 2 clutches (one to disengage the hybrid electric drive at low rpm or it will stall the engines). Both clucthes are automatic.