Forum -
May 10, 2021
Community Contribution - Rainwater catchment
I’ve often wondered why catamarans aren’t built incorporating a rainwater catchment system?
12
comments
We do this regularly on our Beneteau Swift 34 which drains the top deck amidships each side - we simply run a rope from the drain into a bucket and a hose from the top of the bucket into the water tank - the water runs along the rope very nicely into the bucket.
In terms of being sure the water is clean - we use our boat a lot and know our top deck is clean - we wait for a while once it’s raining to be sure before rigging up our rope and bucket.
We were fortunate in enjoying a sail on the Excess 14 at Cannes with you and Thibault in 2022 and so I can say it’s very easy to clean the roof of the boat as a prospective owner.
Roy
Happy New Year and many thanks for your contribution.
I am with you a 100%! With the surface we have on our catamarans we must find a solution to catch rain water. I love the simplicity of your system with the rope and bucket.
All the best,
Thibaut
Maybe there could be a mesh that can be rised at night to get water by condensation? Here a short video about it https://youtu.be/YxRONAZoMDk
Voilà une chose intéressante et nécessaire, c'est même incroyable que ce ne soit pas systématique sur tous les bateaux cat ou mono.
Cdl
The habit at home is to have drinking water for everything. On a boat water can be drawn for different "tanks": salt water is suitable for many things (even a shower to rinse off) and available in unlimited quantity, rainwater is ok for shower or the last rinsing of dishes, finally drinkable water can be reserved for cooking and drinking and does not require large quantities. Having separate circuits and tanks with those different waters and a device to monitor the consumption and to estimate rainwater to come would be my choice.
Best Regards
Olivier
Thank you for your contribution to Excess Lab. It fits perfectly with the concept of the Lab and opens an environmental topic in line with the values of Excess.
Water on board, just like energy, is one of those 'consumables' that can limit our range under way.
Being able to increase our water capacity, in a self-sufficient way, allows us to consider undertaking longer passages... without weighing down the boat!
Desalination systems are of course a first answer, being the most widespread, and best-known and mastered.
It’s a relatively light solution; there’s an unlimited supply of the raw material(!); and it is ecologically much better than drinking water from plastic bottles.
On the downside, it has a high initial cost, requires maintenance, and consumes energy to work...
Rainwater is a less often considered alternative but (on paper) an even more attractive one, because it is totally free and doesn’t require any complex and expensive equipment.
Rainwater can be recovered with simple filters, and consuming no fuel. It’s just that the availability is somewhat... random!
Numerous experiments have been made, from the single-handed sailor taking a simple shower, to the perfected system offering water as pure (or even purer) than bottled water.
Some common points emerge from these experiments:
- The need for a large catchment area: To make the most of the slightest rain shower, you need surface area. From this point of view, a catamaran makes a much more suitable platform than the deck of a monohull!
- Clean catchment area: This input data is less simple, salt water, dust, bird droppings are all pollutants that must be removed from the circuit.
- Good filtration and treatment capacity: Directing rainwater to a water tank, without filtration or treatment, does not provide clean water for consumption.
- Storage capacity: Since rainfall is random, you really need a significant storage capacity to achieve autonomy with rainwater.
With these elements in mind, collecting rainwater on an Excess catamaran seems perfectly realistic. Of course, this is too random a source to fully rely on, but it can be both an economical and ecological supplement to the water carried, for any crew looking to head off on longer passages or cruises and accepting to put up with the constraints of filter maintenance.
Within the framework of Excess Lab, we would be very interested to hear the opinions of other users on this subject: Would the Excess of your dreams have a coachroof designed to collect rainwater? Would you be willing to manage the collection, storage and treatment of rainwater? Everyone's opinion is welcome. If some of you have experience in this matter, it would be very interesting to share it on this thread.
Looking forward to hearing any more feedback, and thanking you again for this very constructive input,
Kind regards,
Hervé Piveteau
Product Manager - Excess Catamarans
BTW, another downside of a watermaker is that sometimes the anchorage doesn't provide you a clear enough water to run it. If you do so, you will need to change your filter pretty often.