twin keels - an alternative

I don't understand why twin keels aren't very popular.
They allow to reach shallow water easier and beck at high tide much easier.

Is the reason costs only?

 

More wetted surface for the amount of lateral resistance they provide and usually they are relatively shallow and very low aspect so they tend to allow a lot of leeway. These are the reasons usually cited for not using them. You don't point as well as a retractable fin or centerboard can get you and there is more friction which slows you down. OTOH...I like them because you can ground upright without jamming anything and you can get at the bottom just about anywhere you can ground and have the water go out from under you. They work well areas where there is a large tidal difference and shallow shores...England especially fits this description...which is why they are rather popular over there.

 

I disagree about the leeway portion of your comments Steve, but agree in the rest. The basic issues are you have deeper draft with bilge keels then retractable boards, so they're not that shallow. Also (as pointed out) they don't offer as good of preformance as other shoal alternatives. Yes, it's nice to take to ground standing up, but if you take to ground when you didn't want to, you can't just heel the boat over and float off, like you can with a fixed, centerline appendage.

Simply put and as with everything in yacht design, you have advantages and disadvantages to consider on every decision. The USA doesn't have (for the most part) the huge tidal ranges that some other areas of the world experience. For example I have a huge spring tide down here of about 3', but typically it's about 2'. The difference between knee or waste deep water isn't enough to get excited about, though if I lived in place where 12' tides where typical, bilge keels would look much more attractive. 305, you have the same tidal range as I do.