If you are going to travel along the beaches this is how you can find out the times of Mean Low Water (MLW) and Mean High Water (MHW) before you travel.
You will need access to the “Admiralty Tide Tables Volume 2 NP202 - Europe (excluding United Kingdom and Ireland), Mediterranean Sea and Atlantic Ocean” published annually by the United Kingdom Hydrographic Office. Your local library should be able to locate a copy and get it temporarily transferred to them. Failing that, try local yacht clubs or ships chandlers.
First of all make sure you are using the correct year. Then look up the tide information for the nearest Standard Port, in this case “Senegal - Dakar” for the dates you are interested in. Now find the time differences for Nouakchott which is a Secondary Port.
All you have to do is add the time difference shown for Nouakchott to the times listed for Dakar. The sequence listing is MHW, MLW, MHW and MLW. Currently (2002) there isn't a difference quoted for Mean Low Water (MLW). Not to worry, it will be similar to Mean High Water (MHW).
It looks a bit daunting, but bear in mind that most of the information is about the height of the tides, which you don't need to worry about.
To get the MHW at Nouamghar, add a little bit more - say 30 minutes.
Finally, bear in mind that all times are quoted as local times, not GMT. Also note that these are predictions based upon average barometric pressures. This means that if the atmospheric pressure is significantly different in the 48 hours preceding any given day, then the tide can be early or late. Also, very strong on-shore winds can keep the tide higher than predicted.