Passage through The Swellies - Lower Water Neaps check/advice

[Marceline]

Hi - I just hoped if anyone could check/offer advice for our planned daysail tomorrow where we want to passage through the Swellies (SW to NE) in the morning at Low Water Neaps, then come back in the evening at HW Neaps

Our draft is just 90cm and have a 6hp outboard petrol - so we really don't want to get the timings wrong etc

I've seen various timings for High Water slack, but we're not as sure when it comes to Low

We did manage this (once) last year following the wonderful Mike's (of Sailing Cos I Luv It) couple of excellent videos, and he suggested going through at 4hours after Liverpool High Water (for the Low Water Neaps passage)

Looking at the tide tables, with DST Liverpool HW is 0603

So would about 10am be ok to try this ?



for the return journey (from Menai Bridge through towards Caernarfon) we planning to come back 2hours before LHW (1856 DST approx 7pm), so returning through the Swellies at 5pm - again just hoping this sounds correct?


Many thanks for any checks/advice (as its def not something I want to get wrong)

 

[Rhylsailer99]

looking at the tides they are very small neaps so I guess if the timing was not perfect the current wont rip like that of a average sized tide.
I still have yet to make the passage myself.

 

[Marceline]

thanks so much - that's really helpful

 

[Skylark]

Hello Marceline, hope you're both well.

I always relied upon my well-thumbed copy of Ralph Morris Cruising Angelsey and the North Wales Coast.

Notes scribbled in the margin of my 25+ year old version say "Menai Bridge towards Britannia HW Dover -0200"

I don't think that I've been through at LW but the book says "passage at LW slack (neaps) is possible and is regularly made by local boats, remembering that slack water precedes LW by the same interval as it precedes HW"

Looking at the tidal atlas charlets, that's leaving Britannia towards Menai at HW Dover +0400

Have fun, fair winds.

 

[vyv_cox]

I have gone through at the recommended slack time on LW neaps several times. This passage was regularly in the programme at NWVYC. IIRC I have seen it suggested that there is enough water at LW springs slack water, bearing in mind that slack and LW are some time apart.

 

[Marceline]

cheers so much vyv_cox (and to the NWVYC ) - We're thinking of possibly joining next year as tbh I've not made much progress this season (mainly me getting some calcs wrong which is why just wanted to double check on here and ask if this seemed ok)

 

[Marceline]

Hello Marceline, hope you're both well.

I always relied upon my well-thumbed copy of Ralph Morris Cruising Angelsey and the North Wales Coast.

Notes scribbled in the margin of my 25+ year old version say "Menai Bridge towards Britannia HW Dover -0200"

I don't think that I've been through at LW but the book says "passage at LW slack (neaps) is possible and is regularly made by local boats, remembering that slack water precedes LW by the same interval as it precedes HW"

Looking at the tidal atlas charlets, that's leaving Britannia towards Menai at HW Dover +0400

Have fun, fair winds.

Cheers so very much Skylark (and to Ralph ) - really appreciated double checking for me

We're good thanks - tbh not been too good a season so far (mostly weather, but also I've made a couple of errors with timings/tides) but hoping if we go tomorrow we'll manage a nice day of things

hoping you're all ok and having a good season and many more nice days ahead (hopefully better weather and fair winds too)

 

[vyv_cox]

This is the chart of the Swellies from the wonderful Glazebrook pilot. Ralph's pilot was largely based upon this work, originally published in Yachting Monthly in the 1950-60s. Depths given are at LAT. There is 1.8 metre depth between Gribin Rock and the beacon at Price Point. High/low water at Menai Bridge is about 1/2 hour before Liverpool, thus the flood/ebb has 1.5 hours to go at slack water. With a total rise of 6.7 metres there should be about a metre in addition to the 1.8 metres at LW springs slack.

The beauty of the passage at LW is that the rocks hidden at HW are very obvious! I suggest you try it at neaps first.

 

[Marceline]

oh wow - many thanks - I never knew there were other routes through The Swellies !

Tbh I think I'll stick to the passage I'd done on couple of RYA courses (and which Sailing Cos I Love it demo'd) but that's fascinating there's other potential ways through

I was also fascinated by this you mentioned:

"The beauty of the passage at LW is that the rocks hidden at HW are very obvious! I suggest you try it at neaps first."

Does that mean it's possible (draft permitting) to also go through at Low water Slack when it's not Neaps ? if so that could be really useful (once we've got the hang of Neaps passages) as tbh waiting 2 weeks for when its Neaps again has been limiting our plans

 

[vyv_cox]

oh wow - many thanks - I never knew there were other routes through The Swellies !

Tbh I think I'll stick to the passage I'd done on couple of RYA courses (and which Sailing Cos I Love it demo'd) but that's fascinating there's other potential ways through

I was also fascinated by this you mentioned:

"The beauty of the passage at LW is that the rocks hidden at HW are very obvious! I suggest you try it at neaps first."

Does that mean it's possible (draft permitting) to also go through at Low water Slack when it's not Neaps ? if so that could be really useful (once we've got the hang of Neaps passages) as tbh waiting 2 weeks for when its Neaps again has been limiting our plans

Yes, that's what my post #8 is saying. There is enough water there even at the lowest spring tides to go through at slack.

Once you have done it a few times you will find it is not necessary to go through at slack water. Provided the tide is with you it is perfectly possible to go through at other times. The last time we went through I motored from Port Dinorwic, through the Swellies a couple of hours before slack water high, picked up a buoy off the Gazelle, ate lunch and came back about an hour after slack.

I know a man who has taken a yacht drawing nearly 2 metres through four hours after slack water high at the Swellies.

 

[Marceline]

really appreciated and very useful info - thank you

 

[peteK]

If you look on the Caernarvon harbour trust website under information there is useful information about passage through the swellies leaving Brittannia rock and Cribben rock to port coming from west which is the route favoured by most as its easier to follow.

 

[IPsailor]

I've attached the Swellies LW transit chartlet that we used to use on the courses run by the Conwy School of Yachting - which closed in about 2012. I moved to sail in Scotland that year so have not done the transit for many years. I suspect the little table bottom right should read Ht of tide slack water NEAR rather than HEAR but have not done the calculations to check. I certainly did the transit many time in my own yacht, draught 1.5m and a couple of times in the school Jeanneaus which I think drew about 2m - but whether at neaps or springs I don't recall

 

[Marceline]

If you look on the Caernarvon harbour trust website under information there is useful information about passage through the swellies leaving Brittannia rock and Cribben rock to port coming from west which is the route favoured by most as its easier to follow.

thanks pete - that's def the route I'm using and its a very helpful link

what I was struggling with on the info from there (and why I asked on here) was I wasn't sure about going through on Low Water slack for the Eastward (SW-NE) passage (though CHT do mention LWSlack for the Westwards passage)

Passage through the Swellies – Caernarfon Harbour Trust

 

[Marceline]

I've attached the Swellies LW transit chartlet that we used to use on the courses run by the Conwy School of Yachting - which closed in about 2012. I moved to sail in Scotland that year so have not done the transit for many years. I suspect the little table bottom right should read Ht of tide slack water NEAR rather than HEAR but have not done the calculations to check. I certainly did the transit many time in my own yacht, draught 1.5m and a couple of times in the school Jeanneaus which I think drew about 2m - but whether at neaps or springs I don't recall
View attachment 181438

thank you IPsailor - that's also really helpful (especially the tide slack table)

 

[Marceline]

HUGE thanks for everyone's help and advice on here - lots here I didn't know (especially that a Low Water slack doesn't have to be on a Neaps!)

With that in mind, we're going to attempt the day-sail again this Sat 17th Aug with a passage SW-NE (Port Dinorwic - Menai Bridge+) around lunchtime and returning NE to SW later in the evening

I've checked (using Dover High Water DHW) and Liverpool HW (LHW) just to see how they compare and they seem very close for Sat

LiverpoolHW - 1005 2225 [DST]
DoverHW - 1002 2224 [DST]

so for simplicity (and that I am planning to be waiting to go through 15mins earlier for each gate) I am using these times of

HW - 1000 2230

[ALL TIMES ARE DST Daylight Saving Time] Sat 17th Aug 2024

Passage SW - NE (Port Dinorwic - Menai Bridge+)
Low Water Slack is HW +4 hours = 1400DST (at Britania Bridge ready for 1345)

Return Passage NE-SW
High Water Slack is HW -2 hours = 2030DST (at Menai Bridge ready for 2015)


hope these look ok and just one thing to double check - these passages will be 3 days after Neaps - I'm hoping the timings are correct for the two tides balance of Slack water, but would/could the currents be much stronger for these passages than back on Weds 14th when it was on Neaps ?

 

[Marceline]

ah heck - I just checked on BBC Weather and Sunset is 20:39 - with us still being novices with this passage should we not go through tomorrow as it will be going dark if we go for this 2030 return passage ? (sadly we can't really stay overnight on a mooring to come back the next day)

edit: The CHT website describes this returning passage as possible to attempt earlier.... hmmm, not sure what to do - would love to try tomorrow as the weather looks really nice, but our 24' sailboat boat only has the 6hp petrol outboard if we get into difficulities

Passage through the Swellies – Caernarfon Harbour Trust
"

WESTWARD PASSAGE​

Timing​

For passage through at High Water Slack the timing is not as critical for the Westward passage as it is for the Eastward passage as the tide will be running with you after the slack. It does not matter too much if you are early as the flood tide will check your progress. If you are late going through then you will be swept through, which means you will have less control, but is fine as long as your vessel is fairly manoeuvrable and you keep out of the eddies

 

[TSB240]

We came through from Felinheli at about 7.15 am HW slack today. Spent the day off Traeth Y Ora (Near Dulas Island)
No sign of any tide at all. It was quite dark when we dropped our mooring off Felin about 6.30 lights were still on Bridge arch but easy to make unlit Pylon transit Prices point and pyramid by Brittania Bridge. In my head the hw slack tides get 45 to 60 mins later approx each day.
HW slack Saturday AM will be 08.00am PM will be about 8.30
HW slack Sunday AM will be 09.00 am PM will be about 9.15
HW slack Monday AM will be 09.45 am

I have to be back in Felin on Sunday especially as it is forecast 38 kts on Monday just when we would be leaving the boat on a mooring.
I will probably come through on Sunday night at about 8.15 1 hour before HW slack. It is quite possible to do this even with 10 hp on neap tides.
Happy to escort you through if necessary.

 

[Marceline]

thats hugely helpful TSB240 and thanks ever so much for the real-life info - sadly we need to try and do this all in one day if possible (rather than stay overnight and come back Sun) so why looking to do the Eastward passage at Low Water Slack and return Westwards at HWslack all on Sat

but tbh if were late and we do end up needing to stay overnight no a Buoy would be very glad of following you back through and thanks ever so much for the offer

 

[Marceline]

so I've also just been working up a plan B - not going through Swellies at all but heading the other direction and going out of the Straits over Caernarfon Bar, and then returning later that evening

We've also never attempted this passage either so again would be very glad of any advice/checks for us doing this with our 6hp sailboat

According to Reeds Almanac and the advice on CHT Website, passage can be attempted over the Bar HW-3 to HW+3 of local High Water (Caernarfon)

https://www.caernarfonharbour.org.uk/wp-content/uploads/buoys-print.pdf

DST Caernarfon HW is 0900 and 2115 on Sat 17th Aug, so it looks like we can attempt:

between 0900 - 1200noon (outwards from Menai Strait with ebbing tide over the Bar)
between 1815 - 2115 (returning over the Bar with the flood into Menai Strait)

weather looks from F3 - F4 (gusting to F5) westerly/south westerly, so with the outwards journey it may be choppy with wind over ebbing tide. I think we'd struggle to return against the very strong tides if we get this wrong so once we get to Belan Narrows, if we decide to go through I think we're commited, so we're planning to phone CHT/Victoria Dock to ask their advice before going through Belan Narrows

We'd then have about 6-8 hours sailing in Caernarfon Bay - 2 people sharing helming and crewing and taking turns/having a rest and plan to just sail on a beam reach back and forth mostly out in Caenarfon Bay (but keeping away from Lee shores). I don't think we'd try anything more ambitious just as a) we've never done this before and b) I think the couple of anchorages out past the bar will be very busy with it being an Aug weekend and nice weather

Does this sound an ok plan (and if we come back into the Straits about 1830 we should have a strong favouable flood to take us all the way back up to Y Felinheli) ? If so I think this plan B might be safer than risking being in The Swellies at 8:30pm if it goes dark if we get in trouble ?

many thanks for any advice/suggestions - we're still novices really around these waters - most we've done is sail up/down between Fort Belan/Abermenai and Plas Newydd, with couple of times through The Swellies, and never yet attempted The Bar)