Planning a south bound passage from Milford round Lands End

This is an example of my planning to round Lands End south bound to be read in conjunction with my page on Passage making up the west coast.

E & OE, see Reeds, other Almanacks or an appropriate pilot and work it out for yourself!

Background.

Written a week, hopefully, before my Autumn cruise in 2025, it will probably need changing as the likely weather window is small but I need to do some work on the boat between now and leaving and so this is the last opportunity to do it before going to the boat, if the weather window changes or the wind is lighter than forecast I'll have to recalculate, but a day plus or minus is a trivial job. Also I have nothing to do today.

I would have prefer to go via St Ives or the Scillies and still might if the forecast changes, but at present neither would be practical with NW winds backing SW, but both are easier to plan than this route so I can easily change if the opportunity arises, even on the way across - it would not be the first time. The good news is that 15 knots of north westerly wind would make for a very quick passage under sail.

Todays ECMWF forecast for 12:00 on Saturday 30th. I'm sure it
will change, hopefully for the better before and after to give me
some flexibility.

Tides.

Lands End with a track of a previous
passage north bound. I would need to
be a bit closer in south bound to get
the early tide turning south.

For the bulk of the trip across the Celtic Sea my SeaPro navigation software can be relied upon to give reasonable timings and a Course to Steer until about the N cardinal buoy marking the "Wave Hub" NE of the Off Land's End TSS, after that there are too few tidal diamonds to accurately cover the critical portion around Lands End, CTS is unlikely to be an issue as that can be eyeballed or the autopilot can take me to a way point but timing is an issue so the text and small chart-lets in Reeds or the RCCPF pilot need to be consulted.

Very close in to Cape Cornwall the tide sets south at HW Dover + 2 hours but is not slack or running south further off shore for another c 5 hours.

At The Runnel Stone, off Gwennap Head just south of Lands End, the east going tide runs until HWD -1 and it is 9 miles from The Runnel Stone to Newlyn and 19 to south of The Lizard. 

Ideally therefore if heading for Newlyn you need to plan to be at the Runnel Stone no later than about HW Dover +5 hours for a fair tide or there will be a brisk one on the nose.

The Calculations.

HW Dover 

Sat 30th August 2025 08:50 and 21:10, 4 days before neaps.
Sun 31st August 2025 09:30 and 21:50

So the optimum time to be close inshore off Cape Cornwall on Saturday would be 21:10 + 2 = 23:10 but more realistically if its a bit blowy some time between  23:00 and midnight or a bit later.

Turning to SeaPro with a plan for Milford to the Fal, leaving Thorn Rock buoy at 05:00L  making 5.25 knots, a reasonable cruise speed motor sailing and understated reaching in a good breeze, I would be at the Brisons by 23:40 local with c 8 miles to run to the Runnel Stone with a following tide, so I would be there about 01:00 on Sunday vs a target latest time of HWD +5 = 02:10L when heading for Newlyn.

I would then have the option of anchoring off Mousehole or Newlyn around 03:00 for some sleep before heading further east or, particulalry if bad weather looked likely, continuing on to round The Lizard against the last of the ebb but with the flood then taking me up to the Fal estuary for St Mawes or The Truro River for a late breakfast or even on to Portmellon, Polkerris or Fowey arriving around mid day. If I felt tired after The Lizard, there are anchorages a couple of miles past or at Coverack.

The timings are quite tight but doable providing the sea does not slow me up. An extra quarter of a knot gives me 45 minutes at The Brisons, any faster and I would need to slow down towards the end - the tide probably doing that for me.