Submarine barrier Portsmouth?

RobWales

RobWales

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I've just returned home after visiting a customer in Portsmouth today and after I left their premises I went for a drive along the front to take in the views (sea looked very inviting)!
Anyways I've read about this submarine barrier thingy that the around the UK racing boys hit at the start of the recent race and was wondering if the large blocks I saw stretching out to sea near the Royal Mrines museum was it?
If not what is it,or if it is why on earth did the racers hit it?
I mean all those posts marking the blocks should have told them no?
Thanks
Rob
 
[ QUOTE ]
as an East Coaster approaching Pompy from the Looe Channel with a foul tide i go through the gap. so far so good /forums/images/graemlins/blush.gif

[/ QUOTE ]

Thanks but without sounding funny, that tells me nothing! /forums/images/graemlins/confused.gif
 
It's very obvious when the blocks are sticking out of the water, and if you're a local, you would know where is it along it's length.

Confusion could arise as it "kinks" close to the Fort at the seaward end, but it is clearly marked on the chart.

dv.
 
Yup, that is the barrier, visible at low water. There are two passages through, well marked and lit. One near the beach, and one mid way to the fort.
I have passed over the blocks years ago, in fog, but not advised!
 
[ QUOTE ]
I've just returned home after visiting a customer in Portsmouth today and after I left their premises I went for a drive along the front to take in the views (sea looked very inviting)!
Anyways I've read about this submarine barrier thingy that the around the UK racing boys hit at the start of the recent race and was wondering if the large blocks I saw stretching out to sea near the Royal Mrines museum was it?

[/ QUOTE ]To answer your question directly - yes that's it.

It looks very easy to pick up when you look along the length of it, especially at low tide. However it is not quite so easy to pick up the gaps when you are approaching from the east in low viz without the aid of a chartplotter - they can get lost amongst the lights of Portsmouth and Gosport. At certain states of the tide there is a cross-current at the gap and on more than one occasion I've had to use a burst of engine to avoid contact with one of the marks. I can imagine racing boats in still conditions having some difficulty avoiding being driven on to them.
 
As said clearly shown on the charts running from the shore to Horse Sand fort. I have only ever seen it once at low water so it could be crossed at high water but with no info on the depths not advisable. The "main passage" is lit but the inner "boat passage" is not. The dolphin marking the southern side of the Main passage is a fairly conspicuous structure

The remains of the other barrier running south from No Mans Land Fort was removed a few years ago.

Submergedbarrier.jpg
 
Many thanks all I think that fully explains the barrier........

Not being from the area I guessed it may be it but not certain hence the posting!

However what was to stop the Sub's going around the barrier?

Cheers
Rob
 
It isn't as far down as the Marines Museum, which is at Eastney. It is further back towards South Parade Pier and only visible at low water although there are posts every so often and a dolphin marking the offshore gap. The first one is below the low water mark.

w050f7.jpg


It is called the Submarine Barrier because it is sub-marine and was placed to stop fast torpedo boats attacking the entrance to Portsmouth Harbour by running along inshore. It was never intended to deter submarines as there is nowhere along it's length where there is sufficient depth for a submarine to submerge.
 
This is it taken from the main passage through (the another one is closer inshore). The picture is 30 minutes before low water, springs:

DSCN0137-1.jpg


The Round Britain race used the area between the sub barrier and the main channel into Pompey as a marshalling area before the start and in the general milling about a couple of boats drifted down over the blocks and damaged their underwater gear.

It is submarine in the sense of being under the water rather than being intended to stop submarines specifically. The purpose is to force shipping to the south of Horse Sand fort.
 
IMHO, the barriers are not well marked on some charts. Confession time for me. Many years ago I went clean over the barrier at night without realising what I'd done until afterwards. Luckily, there was enough water. So I have great sympathy with those race boats that hit it. Perhaps the organisers should have warned the participants at the briefing
 
Re: Submarine barrier Portsmouth

The barrier consists of a line of blocks stretching from Southsea to Horse Sand Fort with marked gaps midway (Dolphin Passage) and close to the beach (Small Boat Passage).
It's the I o W section which runs out to No Mans Land Fort and is now virtually non-existent, but Southsea residents objected to the explosions when the MOD started to destroy their side.

The blocks are about 2m long and spaced a metre apart, so if you're lucky you can actually pass in between; some years ago a local paper showed the top half of a French yacht which got it wrong and foundered just after being rebuilt at Campers.

The well-spaced but unlit yellow posts show the line (with kink) but nowhere is the drying height stated (that's the figure to subtract from height of tide at the time, which calculation when referred to tide gauges on Fort Blockhouse or Chichester Bar tells you how much water there is above the blocks, whether you pass over or unwittingly between.)

Now if you think I'm going to reveal that measurement on this nautical Weakest Link and face a thousand claims for lost keels you're mistaken! All you have to do is drift around in calm weather near low water and draw your own conclusions. An old-fashioned leadline or sounding rod would help - you can't do everything with fishfinder , gps and PC.

Sounds like a job for the Wokingham Mob.

Were those racing hearties in the know or playing it blind? Could have been a bit of both!
 
Re: Submarine barrier Portsmouth

Now here's a challenge

I wonder if it is possible to get more than one boat through Dolphin Passage at a time?

At full planing speed and in line abrest I mean.

I wonder
 
Re: Submarine barrier Portsmouth

Oh come on. No one would be that stupid! /forums/images/graemlins/grin.gif

And if anyone did, there would be loads of posts and pictures of it on here! /forums/images/graemlins/laugh.gif
 
Re: Submarine barrier Portsmouth

[ QUOTE ]
in line abrest I mean

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Fortunately you don't have to be able to spell it to know what to do with it!!

Seriously, if Benjanbav tells us the date, time and barometric pressure (Chimet Archive?) when that pic was taken someone could work out the all-important drying height of the concrete slabs which can be just seen breaking water in the distance.
Let's here from you sir . . .
 
Re: Submarine barrier Portsmouth

I mused about the barrier in this way while doing my YM shorebased, the isntructor was a bit pointed about the existence of two passages shown on the chart, and a rather wider and deeper one maked by two sodding great stone forts each side of it:-)
 
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