Porthcawl

[steveej]

Anyone know the height of the lock gate cill above chart datum and also whether there are any length restrictions for Porthcawl?

Looks like the new boat will be based in Cardiff but I would be a bit of a fool if the length/draft meant I couldn't visit Porthcawl.

Cheers.

 

[Yellow Ballad]

From the marina website

The lock gate cill is at 3.45m chart datum but the access to the marina is 4.95m chart datum.

 

[steveej]

I take it you got that from the Marina website. Doesn't make any sense to me. I think they mean that access to the Marina is 3.45 and the cill is at 4.95 and the Marina website is an error. Otherwise the cill would be lower than the sand directly outside the gate.

 

[oldmanofthehills]

No they mean the cill of the gate is 3.45 above cart datum but the top of the gate is 4.95 so they retain 4.95 minus 3.45 i.e. 1.5 m of water and don't open until tide is at 4.95m

 

[steveej]

Not worded very well then is it. Only 1.5M of water hhmmmmmm. Not a problem with the old boat but most certainly a potential problem with the new boats I'm looking at.

 

[steveej]

Well this is what it says on the Visit my harbor website......

''Once you round the pier head you need to stick close to the South pier until you are abeam the perch with SHM on the top marking the end of the old breakwater; at that stage the inner harbour gate will be easy to identify. There is a cill at the tide gate which is 3.45 meters above chart datum so you will need at least that plus your draft to get in.''

Suggests a minimum depth of 4.95M inside the harbor, which I agree seems far too deep.

I have emailed the harbor master.

 

[Yellow Ballad]

The way I read it is they don't open the lock before the water is 4.95m above CD and close them when the water is below 4.95 so the earliest lock you need sub 1.5m draft, if you go in at HW say 10m then you have 6.55m clearence.

 

[oldmanofthehills]

Its probably nice soft mud in there. However any boat with much more than 1.5 draft is a problem in the Bristol Channel and any cruiser not able to take the ground (bilge or longkeel) is very restricted in the Bristol Channel particularly on the English/Cornish side

 

[steveej]

so..... I called them up and asked a slightly different question.....''what is the least depth inside the Marina and what does it dry to, mud or sand?''. the answer, between 1.4 to 1.5M, sand, but of course we have a bit of silt as well which explains the difference in depth.

I also asked about length, and was advised they like to limit it to 10M, but if the hammerheads are free then not a problem as they currently have a 44footer visiting (probably a motor boat and no keel would be my take on it at that length but I could be wrong).

The next question was about width of the lock gates for which I was told 2.8M! I questioned them again not beleiving them, they were adamant it was 2.8M.

NO, I think he meant at least 3.8M, possibly 4.8M and I have been in their quite a few time on my previous boat. I might need to go and visit my parents who live there and measure it myself.

The cill is at 4.95M chart datum so you need at least this, plus your draft in terms of tide to get in. Not sure who cares that the outside is less than this at 3.45m as that is surely irellevant because you need to be using 4.95 + draft to do your calculations. So visit my harbour is wrong and the Marina website instructions are ambiguous to say the least.

I want to make sure the new AWB fits for a visiting weekend before purchase.

Cheers

 

[Yellow Ballad]

What AWB are you looking at? I would have thought most 44ft yachts (assuming its a yacht) are going to have a decent draft and beam so anything smaller will be ok, just a case or working out depths and timings to get over the cill. All you're going to be doing with a deeper draft if shortening the access + - times.

What are you worried about, grounding inside the marina?

 

[steveej]

What AWB are you looking at? I would have thought most 44ft yachts (assuming its a yacht) are going to have a decent draft and beam so anything smaller will be ok, just a case or working out depths and timings to get over the cill. All you're going to be doing with a deeper draft if shortening the access + - times.

What are you worried about, grounding inside the marina?

So Tom, I think the 44 that is in their now is MOBO as you say most sailing yachts at that length will be pretty deep draft unless they have a swing/lift keel.

HW springs in Porthcawl can be 10M+ so there will be more than enough water to get in if the cill is 4.95M CD. Problem is when the gates close and the water starts sluicing out you need to know what the minimum depths are inside the Marina (confirmed to me by the Harbour Master as between 1.4 to 1.5M.

A bavaria 34 shallow draft is 1.45M so could work but the normal keel would not because you would ground inside the Marina as it is well in excess of 1.5M.

Next consideration is how wide is the gate to actually get the boat through. The Harbour Master said 2.8M, I think he is wrong, but if he is correct there is no way a boat with a 3M beam will be getting in there.

Chart Datum of the approach is irrelevent information because it is always going to be less than the cill, so if you have enough water to pass the cill you will have enough water for the approach.

This isnt always the case in other places mind, especially if there is a sand bar on the approach, not a problem for Porthcawl.

 

[Yellow Ballad]

Interesting, I was assuming they don't loose much water through the gate, or at least slow enough to keep close to their 4.95 mentioned on the website. 1.4m seems very shallow for a boat bobbing up and down abit. Did they say a depth at the hammerhead?

I would like to visit Porthcawl but with a 1.55m draft and a sand bottom I'm not sure it'll be a good idea. Maybe they should get dredging a bit.

Couple of pics of the lock, you should be able to get a rough width from the depth gauge nest to the lock. but 2.8 does sound wrong.

The boat on the hammer head looks a good size

 

[steveej]

so if the short fat bloke is 5 ft tall in your first photo, that gate must be at least 15ft wide. looks more like 4.8m wide to me minimum.

The marina water level at low water will be equal to the bottom of the sluice gate in your first picture and the sand level inside and outside is more or less the same so about 1.5m least depth inside the marina.

I was in there 3 times last season in my hurley 22 and never a problem and that was with 1.2m draft.

guys fishing off the pier can be a problem, so you need a knife ready to cut their lines

 

[Lioness]

I take it you got that from the Marina website. Doesn't make any sense to me. I think they mean that access to the Marina is 3.45 and the cill is at 4.95 and the Marina website is an error. Otherwise the cill would be lower than the sand directly outside the gate.

According to the chart, the approach channel has a 3.6m drying height at CD so the marina cill at 3.45m is lower than the ground outside of it in that channel. Which is fine so long as it remains 3.45m higher than the level of the ground inside of it!
The depth of water in the marina at CD will be 4.95m (which would be the depth of water less any drying height areas or plus any charted depths) and this would be the minimum height of tide before they would open the lock gate so they can maintain that depth.

Of course you would only have 1.35m depth of water in the approach channel and 1.5m clearance over the cill at this height of tide.

 

[steveej]

According to the chart, the approach channel has a 3.6m drying height at CD so the marina cill at 3.45m is lower than the ground outside of it in that channel. Which is fine so long as it remains 3.45m higher than the level of the ground inside of it!
The depth of water in the marina at CD will be 4.95m (which would be the depth of water less any drying height areas or plus any charted depths) and this would be the minimum height of tide before they would open the lock gate so they can maintain that depth.

Of course you would only have 1.35m depth of water in the approach channel and 1.5m clearance over the cill at this height of tide.

No, least depth of water in the marina is not the same as the Cill height. It is not 4.95m as confirmed by the harbor master, it is between 1.4 0 1.5M at low water. The water drains out of the sluice gate in the photo above and end up the same level as the lowest part of the sluice gate, which from the photo looks about 1.5m

 

[Lioness]

No, least depth of water in the marina is not the same as the Cill height. It is not 4.95m as confirmed by the harbor master, it is between 1.4 0 1.5M at low water. The water drains out of the sluice gate in the photo above and end up the same level as the lowest part of the sluice gate, which from the photo looks about 1.5m

1.4 to 1.5m low water depth! Just goes to show you cannot take, charts, almanacs or marina websites at their word I guess. I notice Navionics is showing Porthcawl as a drying harbour

 

[Yellow Ballad]

It might be worth questioning the depths again, if you were told the gates were 2.8m wide and they're not it might be a case the depths have been quoted wrong. I find it very hard to believe they don't have at least a couple of meters of water in the marina, I've not heard of people drying there or having problems, it would be very odd they build marina and not be able to get an <2m draft yacht in there. But it's possible and with the website stating they don't open the gate till 4.95m of water makes me think they must be able to hold enough water between tides to keep deep draft boats afloat.

Have you checked the blue book for any warnings?

 

[steveej]

It might be worth questioning the depths again, if you were told the gates were 2.8m wide and they're not it might be a case the depths have been quoted wrong. I find it very hard to believe they don't have at least a couple of meters of water in the marina, I've not heard of people drying there or having problems, it would be very odd they build marina and not be able to get an <2m draft yacht in there. But it's possible and with the website stating they don't open the gate till 4.95m of water makes me think they must be able to hold enough water between tides to keep deep draft boats afloat.

Have you checked the blue book for any warnings?

I agree I would have expected more depth at low water, but they are mostly small local boats in there. I did speak to one of the local owners I know and he said the gate is 6m wide and depths between 1.5 - 2m

 

[steveej]

1.4 to 1.5m low water depth! Just goes to show you cannot take, charts, almanacs or marina websites at their word I guess. I notice Navionics is showing Porthcawl as a drying harbour

Sailing in well trodden (sailed) areas like the solent, everything is accurate, but sailing in less popular places I always try and get as much info from all possible sources and then form my own judgement. There have been plenty of times the chart plotter has shown green bit where there should be blue bits etc.

Even in the Solent I have noticed incorrect information in the Almanac, so nowhere is 100% accurate. Those proclaiming the Alamanac to be the bible are probably correct, literally - its not 100% factually accurate.

 

[Yellow Ballad]

Blue book doesn't mention the marina and the website hasn't updated the news since 2015, it's a shame there's nothing about berthing fees as that may indicate depths.

This looks a pretty average AWB taken from their website.