HYDROSTATIC HEAD-what does it really mean?

[dazdidge]

Sorry if this has been covered before.
I understand the physics/mechanics of it but what does it really mean in real terms?
I bought a really cheap tent a short time ago for a trip up at the local hill loch...........I got wet!!! (never buy a single skin tent)
So I bought a slightly more expensive one, bear in mind I don't plan on taking it up the hill in winter, so slighlty more expensive really means not so cheap. The hydrostatic head is 1500mm, but what does it really mean? Will I still get wet if it pees down. If anyone has prior experience of it, it is the HIGHLANDER-GLEN Lyon 1, see link below
http://www.highlander-outdoor.com/partnumber.asp?cid=29799&pnid=302145
?25 to me is pretty good for a tent, obviously if I was going out in all weather I would take appropriate kit (borrowed from my uncle) But will this be ok for summer/early autumn use?

cheers
daz

[Fishtales]

Have a read at this.

http://www.outdoorgear.co.uk/infopoint/definitions/hydrostatic.htm

It has all to do with water pressure. The greater the pressure, wind and rain, the more chance of water getting forced trough the fabric if its hydrostatic head is low. At 1500 it is in the recommended area so if it is letting in water it isn't working right so isn't fit for purpose, take it back. Also if you are leaning on your elbow or kneeling this can cause higher pressure at these points on the ground sheet and this forces water through it from saturated ground.

Are you sure it is water penetration and not condensation? Condensation on the ground sheet under your body is normal so get a sleeping mat and put it either under the tent, as I do to protect the ground sheet from stone or twig damage, or inside the tent under the sleeping bag. You don't need one of the self inflating mats, a closed cell foam one is fine.

[dazdidge]

thanks for the reply.
the first tent (single skin) was the one I had the problem with, the stitching was pants! I knew it would be trouble when I realised I could see pin pricks of light through the seams!
The new one however is the one I am concerned about. It looks ok from initial inspection but haven't tested it under the hose yet. I know there is no direct corelation between between HH and waterproofness as the material can be 100% waterproof, but if the seems are crap then it will still leak.
1500HH seems to be ok for all but absolutely chucking it down.
As far as mats go, I have a blow up with a built in pump which works well and takes up less space than my roll mat, but it can take a bit of effort to get all the air out. It's a bit heavier than a roll mat but for short hikes it's fine.
Does anyone have experience of the Highlander tents?

cheers
daz

[Black-Don]

I've never read such complete balderdash in my entire life. Everyone knows a hydrostatic head is what you get if you stand still in the rain with no jacket or umbrolly.  :roll:

[bibio1]

the hydrostatic head refers to the depth afterwhich the fabric of the tent should let in water if it is held under water. So in theory any fabric in a still environment with a hydrostatic head of 1mm should be waterproof. Taking into consideration wind etc 1500mm should be more than enough.

As fish tales says take it back its clearly dos not do what it says on the pack but I would not get into a fit for purpose argument. Bottomline it doesny work.

cheers

paul