Water Ballast for small boats

[bigshrimpin]

Here's an interesting Patent from 1970 from Carl Mosley (SeaCraft).



Patent number 3503358

[Claus Riepe]

Yes, interesting. Waterballast for stability, and at the same time used to improve trim during acceleration and deceleration, in a fairly simple way.
Has the system ever been used in a commercial craft?
C.

[rotfix]

wakeboarders use ballast similar to what i'm reading here. there's also a company with a patented system in production...calabria...patent # 6234099

they have a bladder under the deck and inlets on the transom which are under water when at rest. open the inlets to flood the bladder. get the boat on plane and the inlets are out of water, open to drain. i'm not sure if there's an over-flow line too.

another variation i've seen is to use the vent as the control as was mentioned earlier in this thread. this was done with a baldder above deck. if i remember, a scupper was on the bottom of the hull to force water into the bladder at speed. the vent was opened to evacuate the air. close the vent to hold the water. at rest, open the vent and the bladder empties.

these are somewhat different though since the first requires planing speed and the second requires a bladder or tank on deck. hope this wasn't posted already, i did a quick scan.

[rwatson]

Toot -
Good to see your mind is in top creative health to come up with a good idea, but .. its already 'standard fare'
The Macgregor system works fine with no pumps and doesnt need forward facing holes or any of that stuff (speaking as an ex owner).
Yachts have been using perfectly adequate water ballast for years now, its all been done. Pumping rates are not a problem.
Anything under 30 ft ( down to 2 feet) is no big engineering feet - it works, its straightforard, its not even news.

But here is a twist for you - how about a flexible 'bladder' inside the water ballast container to hold fresh water for the crew. As the fresh water gets used, it is replaced with salt to maintain the ballast.

Keep those creative juices flowing.

[doug kay]

It sounds a good idea and it's something I considered for my Ground Effect catamaran but the extra weight you add to make the container defeats the purpose.