UKH

And that's all of them, completely round and why shouldn't they be you might ask?

I'm currently going through my kit for a trip to the alps so we're doing a dummy pack to decide what to take. I had a leaking bladder last time so I'm going with the plastic bottle,  a 1 ltr Nalgene. Everything packs fine except the water bottle, it creates space in a tight pack due to it being round and fat. Get a flat hip flask shaped one I said to myself, surely somebody will make a flat 1 ltr bottle with a slight curve that will slide nicely into the bag and not waste space....... Usually I say if I can think of it, it already exists, not this time.

Not exactly what you are after but check out hydrapak's range

I've got a square(ish) plastic bottle from the supermarket that used to have orange juice in it. I think it's 750 ml. I use a smaller one (600ml) for a normal days water ration.

Easier to clean, nicer to hold.

At least the Nalgenes have a wide enough opening than you can stuff your pants in them to travel and not waste a ltr of space. 

Not the 1 ltr size you would like, and no slight curve, but this is at least flat:

https://ultralightoutdoorgear.co.uk/boulder-flask-16-fl-oz

There you go: https://www.memobottle.uk/?utm_source=google&utm_medium=cpc&utm_cam...

Sistema do square bottles. Sure I've got a 1L one, though it may be 750ml.

Easier to clean,  no edges or corners. Also a circular plan is the most efficient shape in terms of internal volume : surface area. So it'll use less material to make a circular bottle of a given volume than a square one. 

Round (or more properly cylindrical 😉 ) is pretty much the optimum shape for a water bottle. Flattening it means reducing capacity, so a flat bottle holding 1 ltr will be very tall and wide, and use a lot more material for the same wall thickness, which will up the weight and cost.

Inov8 did hard 250ml flat curved bottles for running vests, but not sure if they're available separately.

British Army water bottle is (I think) 1l and flattened and curved to fit the webbing, but is heavy even when empty.

Beat me to it!

I've got a 1 litre green hydrapak, bought full price from Outside as I had heard so many good things about them. Biggest disappointment in outdoor gear in years! I think I've had it 3.5 years and it's just starting to lose its plastic taste, and that's probably only because of all the different things I've put in it trying to get rid of the taste. I had supposedly one of the first camelbacks in the UK mid 90s, so I've been using bladders and squashy/folding bottles for going on 30 years, along with a whole array of different rigid water bottles. The Hydrapak is the only one that made water taste that bad!
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Stronger for weight, due to circular x-section.

Most efficient enclosed volume for weight of container (circle is shortest perimeter for a given area).

Easiest profile to achieve consistent wall thickness for injection blow moulding.

Heritage... Coiled pots, then turned pots, then blown glass bottles, etc.

Military water bottles are often body-fitting (e.g. classic enamelled steel bottle). I had a cheap polythene bottle as a kid that had two flat sides; they were ribbed for reinforcement. Red stopper, green screwcap.

What about army canteens, they are mainly oval in profile.

Like this?

https://www.amazon.co.uk/Nalgene-Sustain-Tritan/dp/B0BS3SYRBY

So far as maximising the amount of volume in the bottle for a given amount of material to make it that's true, but the OP isn't about the efficiency of the bottle, it's about the efficiency of the pack as a whole with the bottle inside it.

Eg: if you wanted to pack lots of bottles together without wasting any space between them, the most efficient shape would be a hexagon.

There is another thing that I don't think anyone has mentioned yet though, which is related to that - water is not compressible, and pressure within a fluid acts in all directions, so a water bottle with a circular cross-section is one where the water itself will act to prevent the bottle from changing shape when you squeeze it. (If the bottle is full.)

I get that packing around a round bottle is annoying, but something that's much more annoying is if it breaks and leaks in transit.  Corners make that more likely to happen.

Trying to find one online, I think the trick might be to look for a 'canteen' instead of a 'bottle'.

Or any tesselating shape...

Corners are vulnerabilities, yes. In injection blow moulding, they tend to be thinner, as the preform has had to stretch further to reach the corner. But the sharp radius makes them stiffer, so, rather than yielding gently (elastically) like a circular bottle wall, they yield plasticly, and break.

I don't recall ever packing where i didn't have something soft that would squeeze to fill the gaps around a cylindrical water bottle.

If you get a 2l coke bottle and only fill it with 1l of water, you'll be able to squeeze and bend it into all sorts of shapes!

Having had various sizes of Nalgene (original or clones), I'll agree with you about them being a pain to pack, as they're wide and squat.

Couple of years ago, we got given a couple of the promo water bottles from the Euros, which were relatively tall and narrow for the volume and I've been converted. The shape means they're very easy to slide into the small rucksack I use for everyday mooching around without taking up loads of space.

Unfortunately, those ones turned out to be a bit on the fragile side and cracked at the bottom from being knocked on the floor, so I'm on the lookout for equivalent replacements.

So they roll down the hill more quickly.

this is what you need.  Quite an old design though.  Wetting the woollen cover on a hot day keeps the water cooler as the cover dries through evaporation

https://www.blightymilitaria.com/en-GB/ww2-other/original-1955-dated-britis...

you could get a matching map case too

The most efficient shape is specifically the hexagon:  https://en.wikipedia.org/wiki/Honeycomb_conjecture

Edit to add:
For the mathematically minded, here is actual proof!  https://arxiv.org/pdf/math/9906042.pdf

Yeah, very much agree, I like mine as its very practical for big days out which just about compensates for the awful taste. 

I have another 1l soft bottle which is much better but can't for the life of me remember the brand.

Edit: it's a platypus duo lock, allthough I found the clippy bit will rip out unless you reinforce it (in my case by poking holes through with a soldering iron and insering cable ties)

As others have said lots of good design reasons for why they should be cylindrical, but the other major flaw is that they roll. Annoying in many circumstances, but potentially disastrous in mountainous terrain.

My preferred bottle choice is a platypus. If not completely filled they mould beautifully to fit in the pack. Yes failure is a concern, but I've had solid bottles fail in the past, so if this is a real worry (hot days, big routes) spread your water into two containers to limit loss. Unlike solid bottles they don't bounce/slosh when almost empty and it's nice to find your rucksack getting smaller through the day.

I like the highland spring 0.5ltr bottles, nice size to stuff in places and they tend to survive being crushed up and carried empty for filling up later. 

Mother-in-law travels with an old, plastic Gordon's gin bottle with a rectangular cross section not dissimilar in proportions to a scaled up hip flask but without the curvature - pretty ideal, apart from when travelling through some conservative countries' security systems...

For small volumes/areas, different shapes are optimal. For a rectangular area, rectangles are more efficient; hexagons leave unused space.

"There is no visible date on the water bottle itself so it could be an earlier example and is certainly the correct pattern for WW2. The webbing sling is marked with the 1955 manufacture date as well as the makers name and the CN number."

1955? Pah, I once signed out a Browning hi-power, which was actually made in Belgium by FN, and had the Nazi German waffenamt stamp on it. That was around 1998.

Some poor lads probably been issued a water bottle of similar vintage for deployment to Afghanistan.

Hmmm...  

A Tetra would pack better: 

https://www.chasseur.com/achat-gourde-le-grand-tetras-concave-232582.html?g...

And there'd be more room in your wallet.

Maximum volume for a given length and given amount of plastic (a circle is the shape which has maximum area for a given perimeter).

The ideal shape is a sphere (maximum volume for given surface area - except it would roll away).

Just pack clothing around it.

Now I'm off to get pencil and paper to work out the ideal length of cylinder for a given volume (classic A Level maths problem...... ).

It's because water drops are round.  

T.

Also round bottles are much more likely to roll down a slop if knocked over or dropped.

Or take off like a rocket on a snowy slope and hurtle down a couloir almost killing your friends in the process. Or so I'd imagine.

Bear in mind that mathematicians start off with the assumption that all geometrical objects are n-spheres unless explicitly stated otherwise.

Oh, I know. And that they are trying to fill infinite areas or volumes...

I've had two of these in blue, used more or less daily for about 9 years in total. My favourite bottle (reading this back makes me realise how uncool I am). Definitely easier to pack than a cylindrical one.

First one met it's end when my brother threw it down several metres onto a spiky rock while half full.

On the second one the bit of plastic strap connecting the lid to the bottle broke, one of my partners took the lid off near the top of Washington Column (maybe 300m up?) and not realising it wasn't attached just dropped it, amazingly we found it at the bottom after abbing down. Ultimately it too was smashed by throwing/dropping. I've still got it in the cupboard as a bit of memorabilia.

Once I wasn't able to get water out of a constricted drip that someone with a cylindrical bottle could. Bits of the inside can be hard to reach to clean. I'd get another one if I hadn't been given other cylindrical ones, which I should really use up first.

Ancient WD bottle linked above, but for a 'squashed' round bottle try one of these - well tested...

https://www.silvermans.co.uk/products/58-pattern-water-bottle-only

Good price too...

This sort of thing?

https://www.cadetdirect.com/us-pilots-waterbottle-1-pint-olive-green/

Only a pint though. And probably a US oint at that.

Try one of these. Triangular! https://orso.biz/triangle-water-bottle.html

https://www.bergzeit.co.uk/p/nalgene-bottle-rectangular/5057081/#itemId=505... 

1958 pattern still in use into the next millennium. Tradition is important.

In reply to olddirtydoggy:

If the OP is near west Cumbria (or wants to pay P&P / donate £5 to MRT) he's welcome to a 1 litre flattened bottle, although it does weigh in at 225g empty...

Yep, all good points.👍

The Swiss Army seem to have a triangular bottle, too...

That was implied, I think, when I said above "Eg: if you wanted to pack lots of bottles together without wasting any space between them, the most efficient shape would be a hexagon."  Not an infinite number maybe, but lots! 

It was just a throwaway comment really, but I was really surprised to learn that the 'Honeycomb Conjecture' was only proved so recently when I looked it up.  (I also didn't know what it was called - had no idea it was just a 'conjecture' for the first couple of thousand years since it was first written about.)

I thought you were being a bit abstract and thinking of a large number of bottles too when you replied "Or any tesselating shape...".  Clearly you would have been incorrect if you were, and also incorrect in the specific case you mentioned later of a small bounded area such as a rectangle. 

This digression has made me feel pretty silly though, I have to admit! 
Can't believe I actually thought for a moment that you could win a trivial argument on UKC with something as flimsy as a link to a publicly accessible peer-reviewed mathematical proof.

Mine was also throwaway; pointing out that any tesselating shapes fit together without wasted space between them... It's what tesselating means, after all...

Then there's this...

https://www.theguardian.com/science/2023/apr/03/new-einstein-shape-aperiodi...

Ah, I see!  Yes, we agree on what "tessellating" means, but were at cross purposes on the word "efficient".

A circle is the 'most efficient' shape in the sense that it encloses the greatest possible area relative to its perimeter (circumference) - hence why most bottles are round.  But the 'most efficient' shape that will also tessellate is a regular hexagon.

Yes, I saw that article about the non-repeating tessellating tiles at the time - mind bending stuff!  I didn't notice at the time that the writer's name is Cantor.  Speaking of mind-bending maths, I wonder if he's related to Georg Cantor.

I remember looking at that sort of 'efficiency' when mucking about with foil pan supports, and working out the most efficient was with infinite 'sides', i.e. a circle.

For a foil pan support, there are other 'efficiencies', such as stability and packability. A conic frustum is pretty good...

That's easy for you to say.

Your round pan supports reminded me of sinusoidal 'wavy' walls - reckoned to be a more efficient use of bricks than straight ones, because they need regular buttresses for strength.

https://en.wikipedia.org/wiki/Crinkle_crankle_wall

I have observed the same with temporary fencing barriers; they ought to be zig-zagged. Strength in triangles. Like my SqueezeBox Stove...

Steel piling uses corrugation for the same effect. Then there's corrugated iron, and corrugated cardboard, of course...

Oh my goodness! Just logged back in to see if my request has had much response and I was expecting a couple of posts with maybe a link at best.

Thanks for all the replies, I'll be very busy tonight.

Nalgene also makes laboratory bottles in all sorts of shapes, square being one of them. Even very wide‑mouth ones for easier peeing – there their "leak‑proof" guarantee certainly comes in handy

Check your lab‑ware supplier...

For something cheaper, I used to buy VODA VODA mineral water for like a quid or so, their 1 litre PET bottle was square and tall, nice for fitting into the tight side pockets on a backpack.

Not sure the latter is available in the UK anymore, though. I got them abroad.

In reply to Harry Jarvis:

Sadly the size is too small, min of a liter but thanks for posting.

In reply to kestrelspl:

Same again but great looking product.

In reply to Thugitty Jugitty:

Now then! Could be a winner.

In reply to wercat:

Ultralight titanium? Maybe the old boys knew more about bottle design than they do now.

In reply to nniff:

Does that come with or without the dynamite inside it.

In reply to Kimberley:

Looks good for grains and musli, not sure I'd trust it in my bag on the alps. Right shape though.

PET bottles can be softened with heat; a hot air gun, oven, hot surface, hot oil, etc. Create your own custom shape... Keep the threaded part cool so it doesn't distort...

Of course, the other approach is a number of little bottles, e.g. 250ml bottles. They will fit into small gaps, and have other advantages, such as insurance against loss or breakage. But more likely to freeze... Buy them cheaply in your local pound store, filled with something like Vimto...

My mate Mick swears by the multi functional (?) Thors Hammer. 

Not entirely successful...

Started out as a 1.5l Pepsi Max bottle, rescued from the street. Filled with boiling water, it shrank down to 750ml...

That could be the answer.

250ml water

250ml water

250ml vimto

250ml spiced rum

1ltr of perfectly balanced rehydration!