Arzal lock works (Atlantic France)

[Roberto]

Hello,
in case anyone keeps a boat at Arzal, la roche Bernard, etc, or is planning to.
Some big renewal works have just been announced for the lock and related structures: preliminary plans imply the lock will be kept closed during two 4-to-5 month periods in the winters of two following years; they have not decided yet if it will be winters 24/25 + 25/26, or winters 25/26+26/27.
No more details right now, will post if I find any.

 

[Poignard]

Hello,
in case anyone keeps a boat at Arzal, la roche Bernard, etc, or is planning to.
Some big renewal works have just been announced for the lock and related structures: preliminary plans imply the lock will be kept closed during two 4-to-5 month periods in the winters of two following years; they have not decided yet if it will be winters 24/25 + 25/26, or winters 25/26+26/27.
No more details right now, will post if I find any.

Thanks for that, Roberto. I keep my boat on the Vilaine but I had not heard about those dates.

 

[Bobc]

First I've heard of it, but thanks for the heads-up

 

[Roberto]

Embouchure de la Vilaine : 12 M€ de travaux à venir sur le barrage d’Arzal d’ici trois ans [En images]

French friends keep their boat there, the marinas do not know anything in detail so they took the information directly from "Eaux et Vilaine" company.
Interestingly, apart from general maintenance, the aim is to create a system to reduce the salinity increase of the uplock waters with each lock maneuver to help the fresh water treatment plant. Apparently, lock transit times will increase a bit, but it will be possible to use them even during lower river outlet.

 

[Bobc]

They did some work last winter in an attempt to do this, so I guess they've decided they need to do more.

 

[Roberto]

A video describing how this anti-salinity lock will function

 

[Roberto]

Old thread, different subject
The Vilaine river is partially flooding; at around high water they cannot open the gates as salt water would damage the water treatment plant, as a result the water level in the various marinas Arzal La Roche Bernard Folleux etc has occasionally risen to worrying levels, on the internet there are pictures of floating pontoons arriving 10cm short of the end of the metal pilings they are connected to. Boat movements in the river have been forbidden.
There is a public FB group with some pictures
Bei Facebook anmelden
By reading the comments, people seem to be especially concerned by next Saturday/Sunday tides.

 

[Roberto]

Old thread revived: I just read that due to delays to the lock works, the re-opening will likely be not before the end of April (instead of the planned end of March).

 

[Roberto]

Impressive works indeed

from
Travaux Barrage Arzal

 

[Muddy32]

So my plan to launch at Le foleux 19/20th April for my normal circuit of Brittany will be best done anti clockwise?

Is the crane at Dinan still available to raise a mast?

 

[Roberto]

The capitaineries have just sent an email, the first opening is planned for May 1st. They regret the inconvenience etc etc, they say they will try their best to offer some alternative solutions to bring the boats dowstream of the the lock during the month of April. No more details so far, stay tuned.

 

[michael_w]

I got this from Arzal Nautique the other day. Scroll down for the translation. I'm probably launching my new to me boat in May.

Bonjour,



Comme vous le savez l’écluse du port d’Arzal est en plein travaux cet hiver pour la création d’un sas anti salinité.
L’écluse devait rouvrir le 4 avril 2026.
Compte tenu de diverses difficultés, on nous annonce un mois de retard (= réouverture de l’écluse le vendredi 1er mai)
D’ici cette date nous aurons la possibilité de mettre votre bateau à l’eau en aval de l’écluse.
Le ponton d’attente raccordé à la terre sera réinstallé pour accueillir les bateaux après la mise à l’eau.
Nous avons besoin d’anticiper ces prochaines mises à l’eau en aval de l’écluse sur les mois de mars et avril.

Dates des mises à l’eau en aval de l’écluse en mars 2026 :
.samedi 7 mars
.samedi 14 mars
.samedi 21 mars
.samedi 28 mars

Dates des mises à l’eau en aval de l’écluse en avril 2026 :
.du mardi au samedi (semaines 14, 15, 16, 17 et 18)

Hello,

As you know, the lock at the port of Arzal is undergoing renovation work this winter to create a saltwater barrier.
The lock was due to reopen on 4 April 2026.
Due to various difficulties, we have been informed of a one-month delay (= reopening of the lock on Friday 1 May).
Until then, we will be able to launch your boat downstream from the lock.

The waiting pontoon connected to the shore will be reinstalled to accommodate boats after launching.
We need to plan ahead for these upcoming launches downstream of the lock in March and April.

Launch dates downstream of the lock in March 2026:

.Saturday 7 March

.Saturday 14 March

.Saturday 21 March

.Saturday 28 March

Launch dates downstream of the lock in April 2026:

.Tuesday to Saturday (weeks 14, 15, 16, 17 and 18)

 

[Muddy32]

Any further up to date information?

What are the arrangements for launching the other side in April?

 

[Roberto]

This thread on the French Heo forum has some pictures of a couple of boats having just been lifted/launched over the works, no indications of the price though. One is a motorboat the other a lifting centerboard so maybe draft is relevant(?). So far it seems to be on a case-by-case arrangement with the yard.
Travaux Barrage Arzal

 

[Roberto]

From the same French forum thread:
the lock re-opening has been confirmed for May 1st; Arzal marina has sent a message to contract holders wishing to launch their boats on the sea side of the lock (which involves lift out upstream at Arzal --> short road transport to downstream where a second crane will launch the boat) during the month of April. It is subject to type/size of boat, specific conditions depend upon the type of contract one has with the marina. Owners are asked to contact the marina not later than March 21st.

 

[Muddy32]

Dear boaters,
Three months after the start of the Arzal lock works, I would like to update you on the situationifficulties related to a number of unforeseen circumstances on the construction site, combined with adverse weather, have significantly impacted the progress of the work. Despite the implementation of acceleration measures, Eaux et Vilaine, the dam operator, has informed us of a significant delay:Therefore, the lock will reopen for the first passages on Friday, May 1, 2026. Eaux & Vilaine and I are the first to express our regret and regret over this significant setback.Since the announcement of this delay, all our teams at the Vilaine ports have been actively working on alternative solutions to allow you to carry out your boating plans with minimal disruption to your schedule, whether your boat is currently on the Vilaine River or in a port outside the Vilaine.I will get back to you before March 15th to propose some very concrete measures (crane services, adjustments to your contracts, and berthing in ports outside the Vilaine River).Please be assured of our commitment to implementing solutions tailored to each of your situations. Thank you for your patience until our next communication. This time is necessary for us to adjust our organization. Our sole objective is to do everything possible to allow you to navigate downstream of the lock if you had planned to do so during April. I am mindful of the scale of the work currently underway to build a high-performance anti-salinity lock that will allow for unrestricted operation in the future in the event of drought.Thank you for your understanding.Sincerely,Vincent BALEYDirector of the Port of La Roche BernardCompagnie des Ports du Morbihan



those needing it in English.