nortada
Well-known member
Possibly been asked before but can anybody give an accurate air draught?
Various sources vary between 18 & 22 meters!
Various sources vary between 18 & 22 meters!
Ayamonte Guadiana Maximum Air Draught
- Thread starter nortada
- Start date
Mistroma
Well-known member
A friend went through in 2013 with older model of my boat and said I'd be OK.
I measured our air draft very carefully before going under the bridge:
Antenna 0.9m
Mast 17m
Mast base-Water 1.9m
Total height 19.8m Manufacturer quotes 19.25m (this may be without a VHF antenna).
I didn't know the tide height when he went through but decided it should be OK as it was a pretty low tide when I was going up river. However, I also put about 60- 80kg water on end of the boom and swung it out as we arrived at the bridge. We got through easily and I so just sailed through on the return trip (it did look very close that time even though the tide height was less).
So it must be over 20m, not certain it would be as much as 22m but can guarantee 19.8m at low water on dates I made the trip. I think that the tide height was forecast to be 1m for the trip up river and 0.5 m on the return leg (based on Ayamonte). However, I'll need to check the dates to make certain.
It looked as if there were a couple of huge nuts sticking down under the bridge, so I kept clear of these. I hope this helps.
I measured our air draft very carefully before going under the bridge:
Antenna 0.9m
Mast 17m
Mast base-Water 1.9m
Total height 19.8m Manufacturer quotes 19.25m (this may be without a VHF antenna).
I didn't know the tide height when he went through but decided it should be OK as it was a pretty low tide when I was going up river. However, I also put about 60- 80kg water on end of the boom and swung it out as we arrived at the bridge. We got through easily and I so just sailed through on the return trip (it did look very close that time even though the tide height was less).
So it must be over 20m, not certain it would be as much as 22m but can guarantee 19.8m at low water on dates I made the trip. I think that the tide height was forecast to be 1m for the trip up river and 0.5 m on the return leg (based on Ayamonte). However, I'll need to check the dates to make certain.
It looked as if there were a couple of huge nuts sticking down under the bridge, so I kept clear of these. I hope this helps.
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macd
Active member
If it's close to being a problem, you can afford to pay a man to look it up for you
Luckily, I'm cheaper than that: Atlantic Spain and Portugal pilot book states 20.5m at HW, 23m at LW.
MAURICE
Active member
Hi
I went under the bridge 2 years ago at low water. At that time I had the same problem with diffrent heights. My Moody 44 I measured and is 20m. I got under at low water but i still held my breath. I did it several times after but always at or near LW.
After going through there is a deep pool on the port side at that time there was also a disused poonton. I anchored in this pool several times. Lovely and peaceful.
Maurice
I went under the bridge 2 years ago at low water. At that time I had the same problem with diffrent heights. My Moody 44 I measured and is 20m. I got under at low water but i still held my breath. I did it several times after but always at or near LW.
After going through there is a deep pool on the port side at that time there was also a disused poonton. I anchored in this pool several times. Lovely and peaceful.
Maurice
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charles_reed
Active member
20 -23 m, but 5m when you get to Mertola
GrahamM376
New member
If it's close to being a problem, you can afford to pay a man to look it up for you
Luckily, I'm cheaper than that: Atlantic Spain and Portugal pilot book states 20.5m at HW, 23m at LW.
And remember that when the tidal flow reverses at the bridge, it's already 2 hours past LW or, even later if the river is in flood.
Mistroma
Well-known member
I've checked my notes and figures for the trip out from Alcoutim to Ayamonte showed that predicted tide height was 0.7m at Ayamonte (0.9m at Vila Real). I went through at low water with the boat completely upright, air draft was 19.8m and tide was 3 days after a spring tide (30th Aug. 2014). The weather was settled and I wouldn't have expected it to significantly alter the predicted tide height.
It looked very close but obviously impossible to judge from deck level.
My electronic chart said clearance was 18.0m (no ref. to tide height). Pilot book said 20.5m - 23m as macd said. I seem to remember that I saw 22m quoted somewhere else. Various sources indicated that height might be HAT, vague HW/LW or mean sea level.
e.g. Pilot said 20.5m at HW and 23m at LW but max range is around 3.5m rather than 2.5m. So these figures may refer to an "average HW and LW". Things like this made me worry about the vertical height.
I suspected that OP had the same problem as he'd said various sources showed 18m - 22m.
If his boat has an air draft up to 20m then I hope that my data will set his mind at ease.
It looked very close but obviously impossible to judge from deck level.
My electronic chart said clearance was 18.0m (no ref. to tide height). Pilot book said 20.5m - 23m as macd said. I seem to remember that I saw 22m quoted somewhere else. Various sources indicated that height might be HAT, vague HW/LW or mean sea level.
e.g. Pilot said 20.5m at HW and 23m at LW but max range is around 3.5m rather than 2.5m. So these figures may refer to an "average HW and LW". Things like this made me worry about the vertical height.
I suspected that OP had the same problem as he'd said various sources showed 18m - 22m.
If his boat has an air draft up to 20m then I hope that my data will set his mind at ease.
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GrahamM376
New member
Mrnotming
New member
Car dash Cam at the masthead!Or a go-Pro if you are flush!
GHA
Well-known member
Knew there was a thread about this somewhere..
I just went under a couple of times and zapped the underside of the bridge with a laser measurer.
Sunday 30/10/16 at approx 12.00 utc from Bridge to water = 22.22m
Thursday 3/11/2016 at approx 12.17 utc from Bridge to water = 23.25m
Doing a quick revision of calculating secondary ports from reeds both come out very close as 24.35 from chart datum or 21.25m at MHWS ayamonte of 3.1m.
Feel free anyone to check the calcs please, not sure the secondary port differences would be the same for the bridge and ayamonte...
So pose, just in case I better say this is just some fun and it's not at all my fault if these numbers are wrong and your mast ends up in the Guadiana after bouncing off the bridge.
I just went under a couple of times and zapped the underside of the bridge with a laser measurer.
Sunday 30/10/16 at approx 12.00 utc from Bridge to water = 22.22m
Thursday 3/11/2016 at approx 12.17 utc from Bridge to water = 23.25m
Doing a quick revision of calculating secondary ports from reeds both come out very close as 24.35 from chart datum or 21.25m at MHWS ayamonte of 3.1m.
Feel free anyone to check the calcs please, not sure the secondary port differences would be the same for the bridge and ayamonte...
So pose, just in case I better say this is just some fun and it's not at all my fault if these numbers are wrong and your mast ends up in the Guadiana after bouncing off the bridge.
capnsensible
Well-known member
Get ahead, get a HAT.
Sandyman
Well-known member
Just to point out that Pontoon is not disused, though from the state of it you might think it was
It belongs to the owner of the golf club........just over the hill & mostly out of sight. We have used it overnight whilst waiting for the tide. We were told we were welcome to use it if the owners Mobo was not berthed there. If you use it beware...........at LW there is less than 1.5 M at either end. I know.................we went aground 
Baggy
Active member
11m mast Looks close :ambivalence:
GHA
Well-known member
It still looks close even when you know there's a 25' gap
Heckler
Active member
geem
Well-known member
Been through at high water with 21m air draft. We didnt touch but it looked close!
GHA
Well-known member
If anyone is interested I have google earth converted to KAP files which opencpn can read from Ayamonte up to Mertola. I'll upload them to google drive and send a link via email if you'd like them.
Sandyman
Well-known member
Yes please Paddy. Been up as far as Pomerao but not got as far as Mertola. Not much confidence in the hand drawn charts that do the rounds. You still in Alcoutim ?
E-mail in PM. Cheers
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GHA
Well-known member
PM sent with the link, hope it works.
Back to the boat tomorrow then up the magnetic river again,,, "no one leaves 'ere on a boat....."
Hoping to bounce up to Mertola at some point, fitted in round the tuesday music nights
Sandyman
Well-known member
So ive heard
Story fom the ealy 80's about a UK couple who spent 5 years gettinng there boat ready for a circumnavigation. Got as far as the Guadiana & never left Got your e-mail. Tks. Thought OpenCPN opened KAP files. Have OpenCPN but all I get is error messages. Any ideas ? Thanks again,