Hull shape matters part 2

[InterdimensionalPancake]

Part 1: https://steamcommunity.com/app/573090/discussions/0/2281582783355976166/

For my next experiment, I determined if the shape (not just the width) of the bow matters. To do this, I made two identical (same weight, power, and width) boats. One had a blunt, flat bow (another floating brick) and the other had a more wedge-shaped bow.

The one with the wedge-shaped bow had a top speed of around 15m/s.

The brick-shaped one had a top speed that was... greatly varied (due to the boat going up and down like a dolphin, which was most likely caused by the blunt bow shape), but its top speed was approximately 14.25m/s. This was likely caused by the aforementioned "jumping dolphin" motion.

In short, wedge-shaped bows typically make for a more stable, and therefore faster ride, but blunt bows probably wouldn't make much of a difference on larger craft, due to their inherent stability.

Part 3: https://steamcommunity.com/app/573090/discussions/0/2281582783360584834/

[RlyShadow]

I was pretty sure depth had a pretty big impact on speed and not so much shape. I remember seeing somewhere someone did a test where the boat was only a few blocks deep vs one several blocks deep and it was a huge impact. Not so much as water drag but almost like the water seemed...denser i think..Perhaps some testing on depth?

[Siegfried67]

Originally posted by RlyShadow:

I was pretty sure depth had a pretty big impact on speed and not so much shape. I remember seeing somewhere someone did a test where the boat was only a few blocks deep vs one several blocks deep and it was a huge impact. Not so much as water drag but almost like the water seemed...denser i think..Perhaps some testing on depth?

It's the drag caused by the water. Using a sub, i go as fast at 10m deep and 70 m deep. The water doesn't get more dense.
If your hull is lower in water, more blocks create drag, and slow you down. Lifting the hull out of water, even partially, gets you more speed, thus the use of hydrofoils for fast boats.

The long wedges and pyramids (2 or 4 blocks long) behave unexpectedly bad still, creating huge amount of drag. Avoid them as much as possible if you want high speeds.

[InterdimensionalPancake]

Hm. I did not consider that. Nonetheless, it still reduced the top speed.

[GrumpyOldMan]

Originally posted by Siegfried67:

The long wedges and pyramids (2 or 4 blocks long) behave unexpectedly bad still, creating huge amount of drag. Avoid them as much as possible if you want high speeds.

How did you test this?

[InterdimensionalPancake]

Originally posted by GrumpyOldMan:

Originally posted by Siegfried67:

The long wedges and pyramids (2 or 4 blocks long) behave unexpectedly bad still, creating huge amount of drag. Avoid them as much as possible if you want high speeds.

How did you test this?

Guess it's time for me to make a third test!

[Siegfried67]

Originally posted by GrumpyOldMan:

Originally posted by Siegfried67:

The long wedges and pyramids (2 or 4 blocks long) behave unexpectedly bad still, creating huge amount of drag. Avoid them as much as possible if you want high speeds.

How did you test this?

Well, after the new blocks came out, i spent hours modifying some of my boats. Same shape, but smoothed the hull. Lost 1/3 of the speed. Should have gained speed instead, less blocks being used and the hull being more aero/aquadynamic.

[SpannerMonkey]

I'd dispute the alleged excessive drag caused by the longer wedges and pyramids, having re engineered the bows of most of my fleet using them, a fleet which has a joining threshold of 30 knots ( any slower and it simply takes too long to get anywhere), and all my stupidly fast craft (no hydrofoils here ( over 120knots )) now use the long wedges, admittedly there's not actually a lot of craft in the water at very high speed so fluid drag isn't an issue but it would be when getting to speed and I've not noticed any slow down there.

The other side to these long wedges is weight, and the fact that on average they are lighter over a quantity of blocks than most others, redoing the bows on the fleet changed how they all behaved usually moving the centre of mass back and down, which is quite handy, and inevitably because the hulls are in some cases,considerably and most noticeably lighter now, they sit higher the water, so have less drag, meaning i can tweak the ratios a bit and go a bit faster again.

SO it's a balance, and ultimately all about weight and drag, and you have to make choices regarding what you want from the craft, because you can, if you really want to, get good speed from almost anything with a pointy bow, BUT if it sits very low in the water or is very heavy it's going to take an astronomical amount of fuel and be a complete pain to do and use. ( yup I've proof of this in the current fleet)