Originally posted by glen76
not having a bow tank im curious,
1stly where do you put them, up high? down low? over the nose or centre?
2ndly how much capacity and weight do they add??
oh and lastly how the feck do you use em. Is it not an accesory that a well designed and balanced boat shouldnt need
Bow tanks are usually right up in the bow - any well set up performance boat should have its weight down low - a low centre of gravity is important. There are also saddle tanks which are put further back in the boat to add more weight to the boat for very rough conditions.
As far as weight / capacity is concerned it varies depending on the size of boat - a Phantom 18 might only have 50 litres or even less, whilst our raceboat has a 150 litre tank with a 3000 gallon per hour pump to empty it!
They are very simple to use - there is a pick up at the transom which can be lowered to scoop up water, and at 50 or 60 mph you can fill a tank quite quickly! This is often operated by the navigator. To empty the lever (often an adapted gear lever using the same type of cable) is pushed the other way and the fill becomes the dump and the water rushes out the way it came in.
As everything in this world is a compromise you can never have a perfectly designed boat for every condition - these things are usually only found on race boats although some leisure boats intended for "heavy duty use" may also have them fitted - another way of "ballasting" a boat is to have more than one fuel tank so that you can move fuel fore and aft depending on the conditions.
Bow tanks are used when heading into the waves when you would normally trim the engine in to prevent the bow heading skyward - and then emptied when heading downwind when you would normally trim the engine out to prevent the boat from stuffing.
I hope that explains the use of bow tanks - I'm sure someone else will have something to add or tell me I'm wrong!