whats the difference...ballast

[jobi]

both boat 24ft one is 6000displacement and 1500ballast the other boat is 4000displacement with 2000 ballast. how those it compare?

[seabreeze_97]

One quick stab here involves ballast/displacement ratio. They are 25% and 50% respectively. Higher b/d ratios would tend to indicate a boat that would more quickly right itself after a knockdown. However, being a ton lighter, it might be getting knocked down more often. It's just one measure of how a given boat will perform.

[jobi]

ok here where I dont get it, the boat with lower displacement has a 50% ballast/displacement ratio, a lower centre of gravity.

the other boat has much more wieght above and is alot less ballested, logic would sugest this boat to be easyer to knockdown no?

I understand that hull design, beem, WTL all play an important role in how seaworthy a boat is, but given both these boats have similar beem and water lines shouldent the lighter boat be safer in bad weather?

in this case the 6000lbs boat was designed by guy thompson as a sea cruiser, he actualy built this boat as the best possible design for his personal needs (the boat got marketed leter on). the lower displacement boat is a mc-gruger challenger 7.4 and is said to take sirrious winds.

I find both these boats interesting, but I am intriged about thire displacement/ballast ratio and how it works.
rgds

[tommays]

It would really depend on were the ballast is

You could have a HUGE amount of oldstyle internal that would not do as much as a new style bulb on a 7' keel

[jobi]

the thompson has a deep fin keel 4.5ft I think?
the challenger has a longer and short fin keel

the challenger has always been a favorit of mine as I cauld put legs on it and use it at low tide like one uses a bildge keeler. because the keel is flat and very strong.

anyway I optained the thompson so my questions ar purly inquisitive.