DRAGONFLY Trimarans User Forum

I know the politically correct answer: none or the least you can...

However, if one has to cross the Atlantic taking extra fresh water, is it 50 litres on each ama too much?

Where exactly would you place this water, centre or aft?

Or would you try to keep it in the main hull?

From Lagos to Porto Santo (450NM) we were 3 on board. We've managed to use only 30 litres or so and the leg took 3 nights. Later, Southward, with the temperature rising, fresh water consumption clearly increased but we always managed to use only the tank. (I have a salt water tap for washing dishes and so forth), even on the longest leg (800NM) from Gran Canaria to Mindelo, C-V (5 nights). For the transat we might be only 2 on board (max 3, anyway) but I think I'd like to have 200 litres on board (plus 2 or 3 of good rum for the tea).

Thanks, Zé, L'Insolent DF1000-27

Water weighs 1 kilo per liter. I think you would be OK with 50 kilos in each ama. Assuming you are generally going downwind during your crossing, I would place it in the aft compartments (you do not want to bury the bows in waves).

I also think you would do better to put as much as possible in the center hull if you have space. Two reasons:
1) Center hull has more buoyancy.
2) The windward ama is out of the water if there is a good wind, therefore it's weight is acting as it would on a lever and I envision the fulcrum somewhere between the leeward ama and center hull at the mid-point (I think the leverage calculation is a complex question and the center hull may be the fulcrum -- depends on wind load and other dynamic forces. I would like to hear from engineers on this). The cross-beams act as as lever and each kilo of down-force from the total weight in the windward ama equals two kilos of down-force on the center hull.

So if you divide the weight with 50 kilos in each ama (and one is out of the water) you will have 50 kilos less buoyancy in the leeward ama and 100 kilos less buoyancy in the center hull, but if you put it all in the center hull you will have 100 kilos less buoyancy in the center hull only (and full buoyancy in each of the amas).

Further thoughts -- In the 1000 the best place to store heavy items is the area aft of the engine under the helm cockpit floor hatch. You might also be able to distribute smaller jugs of drinking water beneath the berths in the main cabin and under the V-berth, but it would be best not to overload the bow (which already contains the main water tank).

That's where I store most stuff, including a lot of drinking water, the dinghy, its engine, diesel jerry cans, ladder, buckets, … I store the food beneath the cabin berths and the engine spares on the smaller berth. Under my bed I have portable solar panel, barbeque, trolleys and stuff

I am going to try to do a test and put some 30 litres (in 6 cans of 5) in each ama, aft, to see if I notice something.