Riverboat race

[Pds314]

The plan is simple.

Get from 45 degrees South, 47-48 degrees East.

To 39 degrees South.

That looks like this.

 

Rules

You must use a boat, and you must not use ANY thrust engines or aerodynamic surfaces (defined as parts with lifting or control surface modules). Also please no Kraken drives.

The race starts when you begin moving and ends when you are North of 39 degrees South.

 

Scoring:

There are two categories:

A. Speed: get there in the shortest period of time possible. Lower is better.

B. Freight economy: minimize time * vehicle cost / units of Ore carried. Do not clip the ore tanks. Lower is better.

 

 

Edited October 26, 2022 by Pds314

[Nazalassa]

2 hours ago, Pds314 said:

You must use a boat, and you must not use ANY thrust engines

No engines

2 hours ago, Pds314 said:

or aerodynamic surfaces.

So, no propellers? Prop. blades are aerodynamic surfaces.

2 hours ago, Pds314 said:

Also please no Kraken drives.

How will the boat move, then?

[chadgaskerman]

43 minutes ago, Nazalassa said:

No engines

So, no propellers? Prop. blades are aerodynamic surfaces.

How will the boat move, then?

hydrodynamic propellors

[sturmhauke]

Despite the ability to build boats, the game isn't actually Kerbal Boat Program. Water physics are an afterthought and not especially well implemented. Last I checked, Breaking Ground propellers don't work underwater at all, while airbreathing engines work normally. This is pretty much exactly backwards. Plus there are no stock water propellers. You pretty much have to use aero parts to build one, or use a mod. A few people have built rowboats with BG parts, but those are more experimental than practical.

[chadgaskerman]

12 minutes ago, sturmhauke said:

Despite the ability to build boats, the game isn't actually Kerbal Boat Program. Water physics are an afterthought and not especially well implemented. Last I checked, Breaking Ground propellers don't work underwater at all, while airbreathing engines work normally. This is pretty much exactly backwards. Plus there are no stock water propellers. You pretty much have to use aero parts to build one, or use a mod. A few people have built rowboats with BG parts, but those are more experimental than practical.

https://kerbalx.com/chadgaskerman/TEK-66-2-CGN
working propellor, Kerbal boat program argument is null and void, furthermore, skill issue

[sturmhauke]

Yeah, that dual prop is made of elevons, which are aero parts.

[chadgaskerman]

15 minutes ago, sturmhauke said:

Yeah, that dual prop is made of elevons, which are aero parts.

what else are you going  to make a propellor with exactly?

[Samwise Potato]

16 minutes ago, chadgaskerman said:

what else are you going  to make a propellor with exactly?

I believe that's the point they're making, though I think it's turned into an argument about semantics now, and you've both interpreted the rules differently.

Correct me if I'm wrong, but @sturmhauke has interpreted it as a ban on all aero parts regardless of how they're used on the boat, and @chadgaskerman has interpreted it as any underwater parts being by definition hydrodynamic parts, not aero.

Since it's a matter of clarifying ambiguously written rules, perhaps we could stop sniping at other people and wait for @Pds314 to clarify.

While we're on the topic, are hydrofoils legal?

[sturmhauke]

57 minutes ago, Samwise Potato said:

@sturmhauke has interpreted it as a ban on all aero parts regardless of how they're used on the boat

Yes, that's what I'm saying.

Quote

While we're on the topic, are hydrofoils legal?

I would also point out that hydrofoils are generally made of aero parts in this game. Perhaps the rule should be "craft may not leave the water and may only be powered by underwater propellers".

[Samwise Potato]

59 minutes ago, sturmhauke said:

I would also point out that hydrofoils are generally made of aero parts in this game. Perhaps the rule should be "craft may not leave the water and may only be powered by underwater propellers".

Indeed, but if Chad's interpretation of "no aero" is correct, then hydrofoils should be legal too, and I very much like to use them when possible.

[Pds314]

Ok. First attempt (and failure).

I got overconfident using differential steering in 3X timewarp and capsized the thing about 4 ingame minutes later. It is remarkably resistant to timewarp and can survive 4X but bends a little more than I would like in 4X

[Pds314]

Well.... that's just perfect.

I capsized it within 2 minutes of the finish line... If I didn't smash the differential controls all the way to try to avoid literally a second of cosine losses from drifting to one side, I would have gotten under 1:15:00 in the speed category. Still a 0 in the freight category though.

This was by no means an optimal run. I ended up spinning around due to misapplication of differential steering or slowing down unnecessarily multiple times. And the craft is not even close to optimized.

Regardless, I think this more than demonstrates that the challenge is possible. It might be harder if you didn't have breaking ground and had to use stock bearings but I think it is definitely possible regardless.

Cool scenery though:

7 hours ago, Samwise Potato said:

I believe that's the point they're making, though I think it's turned into an argument about semantics now, and you've both interpreted the rules differently.

Correct me if I'm wrong, but @sturmhauke has interpreted it as a ban on all aero parts regardless of how they're used on the boat, and @chadgaskerman has interpreted it as any underwater parts being by definition hydrodynamic parts, not aero.

Since it's a matter of clarifying ambiguously written rules, perhaps we could stop sniping at other people and wait for @Pds314 to clarify.

While we're on the topic, are hydrofoils legal?

Hydrofoils are legal if the parts used to not have the lifting or control surface modules.

Edited October 26, 2022 by Pds314

[Pds314]

Well, I added 3000 units of ore, some outboard stabilizers, and adjusted for the higher waterline. I also decided to disable the solar panels because they cause noticeable aerodynamic drag, and it has enough battery that it doesn't matter.
And because the ore stabilizes it, this made the boat faster.

I now have absolutely zero concern about capsizing and managed to do barely under 1 hour, all at warp 3.

Since the boat costs 169681 including ore, and took 3572 in-game seconds to complete the journey, we can do (3572*169681)/3000 = 

time score = 3572 (lower is better)
freight score = 202034 (lower is better)

Edited October 26, 2022 by Pds314

[Pds314]

Managed an even faster run: 47:30. This was mostly at warp 2 rather than warp 3 because the performance suffered substantially at warp 3. It was also a bit difficult to get up to speed. If you just press Z, it will happily lose traction with the water and stay at 10 m/s and a ludicrous 120 RPM. You need to gradually increase throttle and keep traction with the sea surface.


Time score: 2850.
Freight score: 161197

Drifting backwards because why not.

Edited October 26, 2022 by Pds314

[Pds314]

I would like to point out that there is actually an option, not a particularly great one, for completing the course with an unpowered vehicle.

The end of the course is in fact not in hydrostatic equilibrium with the beginning because Kerbin is both *exactly* spherical and rotating. Once it is stable in a direction and above the threshold for viscous water, my boat can maintain 2.7 m/s due north without power due to Kerbin's rotation. A larger design would be faster. It may in fact be possible to get through the course in a reasonable amount of time using nothing but the Coriolis/Eotvos effect.

 

After some testing, however, it appears that it is highly difficult to get a craft sleek enough to break 9 m/s in this manner to turn effectively without just throwing away all of its energy. Given that it took 25 minutes to accelerate to that speed, that's a problem.

Also my test craft weighs over 5000 tonnes.

Edited October 26, 2022 by Pds314

[Pds314]

Still. No denying it's bizarre to see a boat slowly accelerate to 9 m/s with no power (this isn't an entry and the jets are not even used, I just put them to break out of viscosity, but it was not necessary).

If you ever needed more proof that Kerbin is a perfect sphere and not oblate... well here's 5000 tonnes of ship headed straight for the equator faster than you can run with no power.

Edited October 26, 2022 by Pds314

[Pds314]

13 hours ago, chadgaskerman said:

what else are you going  to make a propellor with exactly?

non-aero parts can totally work as a propellor in water. And if not, paddle wheel. Driving a giant car on floaty tires at the surface can also work.

Edited October 26, 2022 by Pds314

[Pds314]

14 hours ago, sturmhauke said:

Despite the ability to build boats, the game isn't actually Kerbal Boat Program. Water physics are an afterthought and not especially well implemented. Last I checked, Breaking Ground propellers don't work underwater at all, while airbreathing engines work normally. This is pretty much exactly backwards. Plus there are no stock water propellers. You pretty much have to use aero parts to build one, or use a mod. A few people have built rowboats with BG parts, but those are more experimental than practical.

True. I do not expect rowboat entries to be particularly effective. Though I would be very impressed if someone could actually get one to work and maintain high enough speeds to be viable without using rotary motion.

That being said, the bouyancy to drag ratio of a boat can clearly exceed 500 in some cases (else the rotation of Kerbin couldn't move them). So I think it doesn't necessarily take much to keep them moving.

Edited October 26, 2022 by Pds314