Portsmouth (uk) Inner Swashway Local Knowledge

Channel Sailor

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I am fairly new to Portsmouth harbour and have already used the Inner Swashway a few times when the tide is above 2m rise. if I want to arrive from a direction from somewhere between SW to SSW I was wondering if any locals can advise me of the deepest water route (and at what depth CD they reckon it is)? Also 1) any useful transits to take a reliable depth track, both entering and leaving 2) Bearing in mind recent channel dredging, how wide is the channel either side of BC Outer post (E.g before you could run aground on the north end of Hamilton Bank)? My yacht draws 1.55m.

My chart shows a least depth of 0.5m cd quite close WSW of BC Outer Post that marks the entrance. So it could be the answer will be 0.5m.
 

DJE

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You could probably be do a better than 3 hours with that draft. With the previous boat that drew 1.2m we almost never went the long way round. Now we draw 1.7m and go round the outside about 30% of the time. 0.5m at CD is still about right and the old back-bearing of 030 degrees from the Round Tower still seems to work. On the way out it's easy just read the tide gauge off Fort Blockhouse add half a metre and that's the depth in the swashway. Then decide what you need to allow for weather conditions and wash from ships and pilot launches and make your choice. On the way in pass close to the race mark just east of Gilkicker and read the echo sounder there. Whatever depth you have near that buoy you will have about 0.6m less water at the NE end of the swashway.
 
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we also have 1.2m and use it more than the 3 hour rule. i tend to assume the worst and treat it as having zero water at CD but DJE is right; 0.5 is more like it. I'll push it if the weather is calm but with a weather eye on swell and or barometer impact on tide heights. As to the best route - there is a leading line on the admiralty charts but i just pass close to he racing bouy and try not to hit the wall
 

XDC

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i tend to assume the worst and treat it as having zero water at CD but DJE is right; 0.5 is more like it. I'll push it if the weather is calm but with a weather eye on swell and or barometer impact on tide heights. As to the best route - there is a leading line on the admiralty charts but i just pass close to he racing bouy and try not to hit the wall

I was going to say exactly that. I just treat the whole area as zero water at CD and allow for rise of tide and sea conditions. Only ever had one anxious moment where suddenly a line of boats left the harbour seemingly together.

I edged over towards Hamilton Bank and thought I was going to hit. A bit white knuckle but that's the only time in many years.
 

capnsensible

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Its been a while but I used to sail out of Pompey a lot but not since dredging so the pilotage tips I used may well have changed.

The first was on the seaward corner of HMS Dolphin. There was some sheet piling with concrete on top. If sea level was on or above the metal, the Inner Swashway was plenty deep enough for a Sadler 34.

For a transit coming in or a back transit departing, there are (were) two distinct building features. One was a pointy blue cupola type roof. This could be lined up with the right hand edge of a square brick tank? on another roof. Sounds complicated but in reality easily seen and worked for the Inner Swash outside normal convention!

My favourite place to sail out of in the UK.
 

Pinnacle

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You could probably be do a better than 3 hours with that draft. With the previous boat that drew 1.2m we almost never went the long way round. Now we draw 1.7m and go round the outside about 30% of the time. 0.5m at CD is still about right and the old back-bearing of 030 degrees from the Round Tower still seems to work. On the way out it's easy just read the tide gauge off Fort Blockhouse add half a metre and that's the depth in the swashway. Then decide what you need to allow for weather conditions and wash from ships and pilot launches and make your choice. On the way in pass close to the race mark just east of Gilkicker and read the echo sounder there. Whatever depth you have near that buoy you will have about 0.6m less water at the NE end of the swashway.
Wot he said. (y)
 

Aardee

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Its been a while but I used to sail out of Pompey a lot but not since dredging so the pilotage tips I used may well have changed.

The first was on the seaward corner of HMS Dolphin. There was some sheet piling with concrete on top. If sea level was on or above the metal, the Inner Swashway was plenty deep enough for a Sadler 34.

For a transit coming in or a back transit departing, there are (were) two distinct building features. One was a pointy blue cupola type roof. This could be lined up with the right hand edge of a square brick tank? on another roof. Sounds complicated but in reality easily seen and worked for the Inner Swash outside normal convention!

My favourite place to sail out of in the UK.

We sail out of Portsmouth on a Granada 34 (1.8m draft) and also use the metal piling by HMS Dolphin as a makeshift tide gauge.
 

andyp

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Similar to @capnsensible and @Aardee with their makeshift tide gauge at the harbour entrance, when approaching the Inner Swashway from the Gillkicker end, I use the sewage outflow pipe support structure by Fort Monckton to know if there is enough water for my 1.6m draft.
Of course, lockdown has gone on for so long I can’t remember exactly which bit of the structure I use!!
Sadly, when they moved the Gilkicker light out to a post they did not consider adding a tide gauge to it.
 

dom

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They are; he was saying to use the Swashway if there wasn’t enough water for the inner one.

Pete


Yup, I have to regularly use all three routes.
Racing yachts are often caught in the Swashway navigating under the mistaken belief that Wightryder I & II are deeper than they are. They draw just 1.6m, same as the OP!
 

Giblets

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Its been a while but I used to sail out of Pompey a lot but not since dredging so the pilotage tips I used may well have changed.

The first was on the seaward corner of HMS Dolphin. There was some sheet piling with concrete on top. If sea level was on or above the metal, the Inner Swashway was plenty deep enough for a Sadler 34.

My favourite place to sail out of in the UK.

We sail out of Portsmouth on a Granada 34 (1.8m draft) and also use the metal piling by HMS Dolphin as a makeshift tide gauge.

You wouldn't happen to be thinking of the seaward corner of Fort Blockhouse by any chance (underneath the NCI lookout)?

There is a tide gauge on BC4, the first red pile just inside the entrance.
 

lw395

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The inner swashway ad the whole area to the West of the Hamilton Bank basically does not dry.
But bits of it are 'kin shallow at LWS.
There are some lumps near Fort Monckton which are close to drying at a very low tide. Opinions differ as to their exact location and what they are.
The locals race Victory Class boats without much bother at LW, but they only draw about 2ft and are fairly unperturbed at rattling over the alleged lumps at Monckton.

Don't push your luck if the sea isn't flat, AFAIK, the bottom is very hard and the chop can be steep. Basically it's Gosport and you don't want to land there anyway.
 

Goldie

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Like others, I used the steel pilings under the NCI lookout as my tide gauge outbound (If there was about 18” visible, I was fine). Inbound from the West, there were some wooden groins on the beach and (from memory) the 3rd or 4th groin had an old outfall pipe. My rule of thumb was based on whether or not the end of outfall pipe as submerged. That boat drew 1.8m .

CAVEAT: I haven’t sailed into or out of Portsmouth for a few years and certainly not since the major dredging works. If you’re going to use this, please check the visual references for yourself.
 

dom

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I mean, this steel piling malarkey sounds very clever and all that. But isn't the handy datum-based tidal gauge with nice clear numbers painted onto an easy-to-read red and white marked pole so much easier and safer? :)

It is also conveniently placed right at the edge of the small boat channel!
 

DJE

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I mean, this steel piling malarkey sounds very clever and all that. But isn't the handy datum-based tidal gauge with nice clear numbers painted onto an easy-to-read red and white marked pole so much easier and safer? :)

It is also conveniently placed right at the edge of the small boat channel!
Some peoples' minds work differently. If conditions are a bit borderline I will always read the gauge or check the depth at the race mark whereas Sue will just look at the water against the shore and say something like "too much beach showing" - and annoyingly she's usually right. But that comes after hundreds of trips in and out of harbour.
 

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