Colin Ibbotson Talks Tarps – Andy Howell - Andyhowell.info

Colin Ibbotson Talks Tarps
Colin Ibbotson is one the UK’s most high profile, ultra light,
backpackers.
In this article he talks about the use of tarps in the UK. Colin’s shares
with us his own personal tarp story, describes the gear he will be using
in 2009 and speculates how his use of tarp shelters might evolve in the
future.

Using Tarps in the UK
I think it’s fair to say I’m passionate about tarps. I now only use a tarp or
Tarptent and have done so for the last four years. I finally sold my one
remaining tent earlier this year, a Hilleberg Akto that had been gathering dust in
the loft. What amazes me is the amount of nonsense written in some magazines
and on the web about tarps. You will often hear people say that tarps are just
not suitable for use in the United Kingdom. They say you will get soaked with
rain or condensation, that tarps are not strong enough, that they are no lighter
than a tent and if the weather doesn’t get you then the midges certainly will. All
these statements do have a scrap of legitimacy but all can be quite easily
overcome if you are willing to adapt your routine ever so slightly.
For me the advantages of tarps far out way the minor inconveniences.
Advantages like a significantly reduced shelter weight and pack size, simplicity
and therefore quick pitching, freedom to change the style of pitch depending on
weather conditions and the most important advantage is less isolation from the
environment. I really enjoy lying fully protected in my sleeping bag, warm and
comfortable watching the night sky go by. I find this puts everyday life problems
into perspective so that they suddenly don’t seem so important anymore. I have
never had that feeling of total relaxation and freedom in any tent.
My objective with this tarp project was to build a tarp with the strength and
stability near that of my Akto but with a total weight of less than 600g. This
mythical tarp still eludes me and maybe it always will but each year I am making
some progress. Few tarps are commercially available that meet my needs.

Almost all are built for the US market and weather conditions. I’ve had to modify
or custom build all my tarps. The nearest commercial tarp I’ve found that is
close to my needs is the Mountain Laurel Grace range of tarps. My 2009 Tarp is
a significantly modified Grace Solo tarp and though still in the early days of
testing it appears to be a major improvement over the 2008 Cuban tarp it
replaces.
I hope in the article to describe my thinking about tarps, tarp designs and what
materials that are suitable for UK winter/TGO Challenge use. I will also describe
my slightly unusual tarp for the 2009 TGO Challenge. You may find it surprising
that I group winter and the TGO Challenge together after all May should be a
fairly warm and settled time of year. However after this years near perfect
conditions some (particularly if you are from overseas) may be unaware that
heavy snow was still falling up to a couple of days before the Challenge and that
strong winds, heavy rain and some snow is still quite likely at some point on any
Challenge.

A Tarp is a Tent!
Henry shires Contrail Tarptent on the 2007 TGO Challenge
(753g)
Think about that. Almost certainly your tent will be of double skin construction
comprising of a waterproof outer and a sealed, bug proofed, breathable and
water resistant inner. In that inner you are protected from the elements but that
same inner will nearly always totally isolate you from the outside environment.
Now examine any of my tarps, they also have a waterproof outer and a sealed,
bug proofed, breathable and water resistant inner (bivi bag). They are no
different except that at least one end is wide open so you still have some contact
with your surroundings. I look at all my tarps as being tents just stripped down
to the bare essentials.

It’s difficult to define at what point a tarp becomes a Tarptent but for me a tarp
will usually be open at both ends. It is unlikely to have a built in groundsheet or
any bug protection as standard. Pitching a tarp can be done using your walking
poles and the pitch style is usually only limited by your imagine. A Tarptent on
the other hand will generally look very tent like and it often has little luxuries
like bug protection and a groundsheet sewn in. Tarptents can usually only be
pitched in one way just like a tent. They sometimes also require the use of
custom poles. Both tarps and Tarptents will be of single skin construction until a
bivi is added.
I like Tarptents but they are generally a bit heavy and because of the sealed end
(or ends) can suffer from much more condensation than true tarps. Tarptents
can make better shelters than tarps if you are expecting too spend a lot of time
in it. A tarp is often the better option if all you want is to pitch and rest at the
end of a long day and then set off early the next day. A tarp will almost certainly
be used in conjunction with a waterproof or water resistant bivi bag in the UK
while a Tarptent probably wouldn’t. The added protection offered by most
Tarptent makes the bivi unnecessary. You could do without the bivi bag even
under a tarp for even greater weight savings and in summer I often do that but
unless you carry a larger (and heavier) tarp then on the Challenge you could end
up getting a little wet and cold.

Ditch Your Tent!
Maybe not just yet. Of course there are some compromises to be made. With my
tarps you are either in or out. There’s no lounging around when it’s cold and
windy like in a tent. With the tarp pitched correctly with its tail into the wind you
will be blasted by cold air in the wind tunnel that you have just created. Get into
your bivi bag (inner tent) though and there’s little or no difference.
Pitching side into the wind would give protection from the wind but also exposes
the major weakness of a standard catenary cut tarp in UK conditions. That is
crosswind stability. A standard tarp will have a pole at both ends and 8-9ft of
unsupported material dangling between them. Pitched tail into wind that’s not a
problem as it can be easily tensioned but from the side that same stable tarp will
turn into a big sail. Lightweight catenary cut tarps really need to be tail into wind
at all times and that may mean getting up in the middle of a cold and wet night
to re-pitch (sometimes more than once).
Other tarp designs can alleviate or totally rid that problem (some Tarptents can
be very good) but all I’ve looked at would take me above the 600g total limit
that I have set and because of the closed construction would suffer copious
amounts of condensation.

Bug Protection
Large bug net fitted over a sleeping bag
A big deal is made of the fact that if you dare to tarp in Scotland in midge
season then you will be eaten alive. That simply isn’t true. There are many
effective methods of bug protection available. I use a bivi with built in bug net or
a large bug net that can fit over the top of my sleeping bag should I not be using
a bivi. When in the bivi you are just as protected as you would be in a tent.
Think about this example. How many times have you been laying in you tent

just dropping off to sleep when you heard that sound that brings fear to the
hardiest of campers? That is of course the sound of the dreaded midge that you
missed when you did your pre-lights out bug squash. You then spend the next
ten minutes chasing the little bugger round the tent. Pleased with yourself you
turn off the light only to hear that sound again…Ahh! By the time you are finally
bug free sleep has long since left you. Now consider this after climbing into your
bivi and sealing it up you can swiftly locate all your flying friends which can then
be quickly eliminated simply as they have nowhere to hide. Within 30 seconds
you are bug free, fully protected and ready for sleep.
Bivy Bags
I consider a bivi bag to be essential for my winter/TGO tarps. The bivi is my
inner tent and does exactly the same job. It fends off any wind, drops of rain or
condensation that would otherwise find your sleeping bag. It keeps you bug free
and is also the groundsheet. The choice is between waterproof or water resistant
designs. Waterproof bivies have the advantage of being able to be used
independently of the tarp should you not be bothered to pitch the tarp. With a
waterproof bivi you could use a much smaller and lighter tarp that just protects
the head area. The problem with waterproof bivies is weight and condensation.
Given the right conditions condensation will form on any waterproof material,
that’s fine for the odd night out but if you use that type of bivi day after day in
UK conditions then your bag does steadily become wetter and wetter. That’s just
not an option for winter use.

I discounted waterproof bivies until I tried
an eVent one last year. The breathability of
that bivi was way, way better than any
other material I had tried. I find eVent to be
only slightly more condensation prone than
my pertex water resistant version. That
doesn’t mean it was always condensation
free but any build up was light and easily
managed. Weight of the lightest eVent
bivies starts at 300g which is a good 100g
heavier than a pertex version. That weight
increase has to be taken into account with
that you can get away with a smaller
(lighter) bivi.
I tried this for 2008 using a Cuban fibre tarp
and an eVent bivi. The bivi worked well but
the tarp not so. Generally I use a water
Bivi with built in bug net
resistant bivi with a pertex upper and
Silnylon bottom. This gives maximum breathability with more than enough
moisture protection and has a good bug net sewn in that doesn’t restrict my
views. Most tasks can be carried out in that bivi. I can eat and change clothing
in there; it is of course a little more difficult in a cramped bivi than a large tent
but still quite possible.

Condensation
With most tarps you will have LESS condensation than in ANY tent. The reason
for that is simply increased ventilation. Using an open-ended tarp in the UK
(windy) environment I rarely suffer any condensation at all. Should you have an
unusually still night then copious amounts of condensation will form which your
bivi (inner tent) will deal with just the same as when in a tent. I have
experimented with adding a rear panel to tarps for increased weather protection
and that worked but really does reduce the airflow through your tarp and
therefore expect increased condensation. Should I choose to have a sealed rear
tarp then I always make them foldable and then only use them when really
needed. Tarptents are likely to suffer from a lot more condensation than a tarp
simply because they try and protect you more from the elements. Well designed
ones such as from Henry Shires have an effective venting system but on a still
night an absorbent cloth will still become your best friend. On those nights I
wipe the tarp down before settling down and do the same again before I start
moving around in the morning. Sounds a pain? Yes it is, but with a well designed
Tarptent this is something that you will do only on still nights. How many of
those do we have?
Tarp choice
There are many different types of tarp/Tarptents; some are simply single skin
tents while at the other end of the scale some barely cover the head area of a
waterproof bivi. It’s beyond the scope of this article to go through all designs but
this is what I look for in a winter/TGO Challenge tarp.

It must be light
With quality lightweight tents available at less than 1kg any tarp has to be
significantly lighter. I set 600g as the maximum for a winter/Challenge tarp and
less than 400g for my summer shelters (all weights are trail weights and include
pegs/guy etc).
Size
The tarp needs to be just big enough to totally protect the bivi in any conditions.
Any larger will just result in increased weight and not extra protection. Small
tarps are also less affected in high winds unless you have some serious pegging
or guying systems which will add weight. I find if I’m using a water resistant bivi
that I want a tarp to be no more than 9ft in length and about 7ft at its widest.
Tarps for fully waterproof bivies can be much smaller.
Keep it simple
Features only add weight. I don’t add weight by leaving pockets, stuff sacks,
hanging loops etc out of the design for my tarps. But I don’t compromise on the
number or quality of the guying points (4/side on a small tarp) and all the
guying points should be strengthened. Seams are a weak point and should be
kept to a minimum.

Catenary cut
A simple 9*7 sheet of nylon will be very light and not having any joins it will also
be very strong. Perfect you may think. Unfortunately it will also be hard to get
the fabric taut which can cause flapping in the wind. A flapping tarp places extra
stress on guying points and the noise becomes irritating and can even cause
sleepless nights. That un-tensioned material also allows the wind to get a good
hold making it a weak design. A catenary cut (curved) tarp makes getting a taut
pitch that much easier but induces a weak spot with the extra ridge seam. The
shape of the tarp also limits your pitching options. My winter/Challenge tarps are
all catenary cut designs but for summer a simple sheet is just fine.
Open front/rear end
Tarps with a sealed rear
panel do offer increased
protecting from the elements
and allow you to get away
with a shorter length tarp.
This would also be a little
lighter but because of
reduced ventilation
condensation is drastically
increased. I want minimum
condensation so all my
recent tarps have open front
Cuban fibre catenary cut 2008 tarp
(601g)

and rears. I have experimented with rears that can be opened or closed as
needed and they are effective but the closing mechanism and extra material will
add some weight.
Materials
Most tarps are made from Silnylon, Spinnaker or Cuben fibre with the weight
reducing in that order and the cost of manufacture increasing. I have tried them
all and they all have uses.
Silnylon
Sinylonwill be the most familiar and there’s a good chance that the tent you now
own will be made out of it. Standard 1.1oz/yard_ silicone impregnated nylon
(Silnylon) is cheap but quite light and fully waterproof. It is also very strong and
easy to work with. The biggest problem I find with Silnylon is that it will stretch
significantly, particularly when wet. You will have to adjust the tension a couple
of times after pitching. I re-tension my tarp before settling down for the night
and then again when I wake up. My first tarps were made from Silnylon before I
moved on to the lighter and more exotic alternatives but after trying these I
have returned to Silnylon for my winter/Challenge tarps because of its strength
and durability. It’s an old material but it still has its uses.
Spinnaker looks quite similar to Silnylon but is thinner and less flexible.
Generally 0.9oz/yard_ is used so it’s a little lighter than Silnylon but does have
another big advantage. That is a near total lack of stretch meaning that when

your tarp is pitched taut it will stay that way all night. Spinnaker isn’t as
forgiving as Silnylon and has a reputation for failing catastrophically and without
warning when its limits are reached. While this has never happened to me the
possibility that it could rules this material out for my winter/Challenge tarp. It’s
a fine material for summer tarps though. Spinnaker can also be a noisy material
in the wind and I always carry ear plugs to use while sleeping should the wind
pick up
2006 Spinnaker tarp with folding rear doors
(489g)

Cuben fibre
Cuben fibre looks very thin and weak but is actually amazingly strong for its
weight. At around 0.6oz/yard_ it is much lighter than Silnylon. It’s made by
sandwiching Spectra fibres, usually orientated in a crisscross grid pattern
between two layers of Mylar plastic. This is a hard process and that’s reflected in
the cost of the material. Like Spinnaker it has little or no stretch and is a very
flexible and quiet material in winds. Its weakness is puncture resistance.
Puncture it and it can tear quite easily until it reaches one of the Spectra strands
sandwiched between the sheets. That in itself isn’t that big a deal and can be
repaired easily with tape. What is a problem is that all the guying points and the
ridge seam still has to be sewn meaning that you introduce hundreds of tiny
puncture points which seriously weakens the material. Manufactures are aware
of this problem so use bonding rather than sewing as much as possible therefore
minimising the amount of material weakening. That’s all well and good but as far
as I’m aware every manufacture still sews the guying points because these will
be under tremendous pressure and bonding alone isn’t adequate. It’s these
guying points where I have experienced problems with Cuben fibre tarps.
My 2008 Challenge tarp was constructed out of a heavy duty Cuben fibre but
even so after six months of weekend use and one Challenge it was only fit for
the bin. All the stitching at the guying points but particularly the ridge guying
points had started to pull through the plastic Mylar film. Some tarps are
constructed with Silnylon reinforcing at the guying points and that may help the
situation I haven’t tried that yet so can’t comment if it works. If I was to try

Cuben Fibre again then that is one feature I would look for. From my experience
Cuben fibre is not suitable for prolonged use in a windy environment i.e. the UK
in winter. For the rest of the year though Cuben fibre is perfect and my two year
old summer Cuben tarp shows little signs of wear.
2009 Winter/TGO Challenge tarp
My tarps are evolutionary; each tarp has been used to test an idea that had
been floating around in my head. The first few were all about reducing the size
and weight to a minimum. Then I moved on to the testing of new materials.
From these results I found that a properly constructed and pitched 600g shelter
can survive in UK winter conditions without me lying awake all night worrying
when it will collapse. It taught me that Spinnaker and Cuben fibre are not
suitable materials leaving me back with Silnylon.
For 2009 I’m concentrating on improving strong wind stability. Tarps or tents
with large areas of unsupported material are never going to be stable in a strong
gusty wind.

2009 Silnylon tarp with triple front/rear guying
system (595g)

The key to stability is fabric support and tension. This can come
from adding more poles or extra guys and pegging points. Poles
are most effective but are heavy and not convenient to carry so
I’ve gone down the guying route. I always have 4 guy
points/side even on small tarps that help spread the wind
generated load and increase panel tension. The 2009 tarp has
also gained four side panel guying points and a triple front/rear
ridge guying system.
The side panel guys make a big difference with cross winds while
the triple guying system considerably increases tension
throughout the whole tarp. I think this is quite noticeable in the
pictures and has made this tarp the most stable lightweight
shelter I have used. Though its still early days and testing will
Conventional
linelocs
continue throughout the winter this years improved guying system has been a
substantial step forward in my quest for better tarp stability. Some other
changes over the 2008 model are quite subtle. The linelocs fitted to the tarp
perimeter are of the type that allows the guys to be adjusted to
any length simply by pulling the line. This has the advantage of
allowing you to adjust tarp height from right down to the ground
when full protection is needed to a couple of feet or more off the
ground should you want that. Conventional linelocs have limited
adjustment and prevent you from doing that, you can have one
height or the other but not both extremes. Nothings perfect and
to prevent guy slippage you need to use thicker and much
heavier cord which is why only the perimeter guy points are
Easy adjust linelocs

fitted with these. Side and ridge guys still use the conventional linelocs that you
will probably find on your tent. Total trail weight of this 2009 tarp is 595g in
Silnylon. Size is 8 _ (length) * 7ft (front) and 5ft (rear).
2009 Silnylon tarp with triple front/rear guying system (595g)

The Future
This isn’t the end and I’m still working towards that
mythical perfect sub 600g tarp. I already have some
ideas for 2010 and these should offer further
improvements to stability with a slight weight reduction
and a tidied up rear guying system. This tarp hasn’t yet
been built and over the next 12 months I’m sure I will
think of other small improvements. These if worthy will
be incorporated into the 2010 design. The last four
years has been a journey. A journey that I have
thoroughly enjoyed, I have learnt a lot and my tarps
have improved considerably. Perhaps more importantly
so have my own skills, you can have the finest tarp or
tent in the world but to get the best out of it you need
to learn how to use it properly.
I’ll leave you with a quick Photoshop impression of
what 2010 might bring…
Colin Ibbotson
2010 version?