oakleyb
Well-Known Member
Does anybody know when the flooding tide at its weakest during a spring tide, is it weaker nearing the HW or LW time, Or if you can tell me the best time to exit this Saturday even better
Portsmouth Harbour Entrance
- Thread starter oakleyb
- Start date
Blue5
Well-Known Member
HW 12.45? ........I think, not near any tide tables at the moment.
Pinnacle
Well-Known Member
HW P'mouth this Sat, the 1st Sept 2012, is 12:47BST. Ht is 4.8m so its a pretty big spring. So, if you want to exit the harbour when there is little/no flood or ebb, I would suggest trying at 13:00BST.
MARGETTS
Well-Known Member
Depends where you want to go.
High water to go west with the tide, Low to go east with the tide.
Bear in mind the eastern harbours are tidally restricted as is Bembridge.
In truth, you can go out of the entrance anytime as long as you are not trying to row against it. It might just get a bit slow punching the tide if you have a small engine.
The strongest bit is the short run between the small boat channel and Haslar lake. Only about 100 meters of strong tide.
Be aware of the sideways momentum which will push you towards the deep water channel immediately after you leave fort blockhouse.
Have fun
High water to go west with the tide, Low to go east with the tide.
Bear in mind the eastern harbours are tidally restricted as is Bembridge.
In truth, you can go out of the entrance anytime as long as you are not trying to row against it. It might just get a bit slow punching the tide if you have a small engine.
The strongest bit is the short run between the small boat channel and Haslar lake. Only about 100 meters of strong tide.
Be aware of the sideways momentum which will push you towards the deep water channel immediately after you leave fort blockhouse.
Have fun
Seajet
...
oakleyb,
I am not being rude, but I see from your profile you have a 33' cat based in Portsmouth; a serious look at a tidal atlas and / or the tide flow chartlet diagrams / diamonds would be a good move.
A tidal atlas or the diamonds on the chart, depending whose charts you use, will also show the direction of flow in the Solent.
For instance at Chichester entrance the flow outside starts going Westwards about 1.5 hours before local High Water.
I am not being rude, but I see from your profile you have a 33' cat based in Portsmouth; a serious look at a tidal atlas and / or the tide flow chartlet diagrams / diamonds would be a good move.
A tidal atlas or the diamonds on the chart, depending whose charts you use, will also show the direction of flow in the Solent.
For instance at Chichester entrance the flow outside starts going Westwards about 1.5 hours before local High Water.
oakleyb
Well-Known Member
not worried about the rudeness as If i had them with me then i'd look, i'm just wondering if the flow is as strong for the entire flood or are there windows when the flow is less.
Seajet
...
I take it you are familiar with the 'Twelfths Rule' ?
Tide comes in 1/12th 1st hour, 2/12ths second hour, 3/12ths 3rd hour, 2/12ths 4th hour, 1 /12th 5th hour...
Basically means the tidal flow builds up to max at 3 hours before & after HW, tapering off to zero at HW & LW.
A rough guide but it generally works well enough at simple places like Portsmouth, doesn't work at all at places like Poole with weirdo double tides !
Adonnante
Well-Known Member
HW Portsmouth 1248bst 4.2 range (a biggy), according to the tidal curve the least flow on a rising tide is between -5 and -4 hours before HW.
Peter.
Peter.
DJE
Well-Known Member
Last edited:
Boomshanka
Well-Known Member
If you change it to 'Max graph size = 1 day', put the BST 1 hour on and then scroll down you'll see the flat 'stand' around HW for Sat 1st Sept, rather than the relatively quick turnaround at LW (which is what the OP was asking about, I think)
Adonnante
Well-Known Member
Better curves here...http://www.hcsc.org.uk/Hurst Point Perpetual Tidal Curves 2012.pdf
DJE
Well-Known Member
I worked out how to grab the image after your post!
colingr
Well-Known Member
That only adds up to 9/12ths
I think there's another 3/12ths after the 3rd hour to make it work
Seajet
...
That only adds up to 9/12ths
I think there's another 3/12ths after the 3rd hour to make it work
Yes I realised that afterwards, but you worked it out didn't you !
benjenbav
Well-Known Member
Some tidal stream chartlets here:
http://www.visitmyharbour.com/harbours/solent/solent/charts.asp?cattype=5
http://www.visitmyharbour.com/harbours/solent/solent/charts.asp?cattype=5
