Swing Keels -- Pros? Cons?

[Rohan]

Originally Posted by Dockhead

If the ballast is in the swing keel, then the weight will be on the contrary less. Because the ballast is more effective, the deeper it is placed, so you need less of it.

What you say may be true in cases where all the ballast is in a stub keel, and the board is not ballasted, but I am not considering such an arrangement.

In most of the arrangements described in this entire thread, all the ballast is in the long swing keel. But doesn't that still require significantly more weight than a standard fin keel with a bulb? Because the nice thing about a bulb is that concentrates the weight as low as possible.

[Polux]

Originally Posted by Rohan

In most of the arrangements described in this entire thread, all the ballast is in the long swing keel. But doesn't that still require significantly more weight than a standard fin keel with a bulb? Because the nice thing about a bulb is that concentrates the weight as low as possible.

As you can see on the picture that kind of swing keel are also kind of bulbed in a sense that they ate much more heavier on the bottom than on the top. Look where the CG is:

Besides that, typically on a boat that has a swing keel as an option to a torpedo keel (much more performant than a bulbed keel), the draft on the torpedo one is about 2/2.20 and the draft of the swing keel 2.5/2.7m. I have seen that on most cases with this draft configuration the swing keel and the ballast it has is normally just a bit less than the one on the torpedo keel for generating the same RM.