Re: Full or Shoal Keel on New Oyster 575?
While as you say, you may need a bit extra to eat a sandwich with a shoal vs a deep. Assuming you only sail 10-50 miles to a place, anchor/dock etc for the night. Lets look at this from say a 2000 mile jaunt! A typical shoal vs deep draft is slower by 20-30 secs a mile in PHRF ratings. With this in mind, I realize put an AC crew in the shoal draft with bad sail, they will knock the socks off of a very well prepped but poor crewed deep draft of the same model!
lets say it is 2000 miles, at 20 secs a mile that is 28 hrs or there abouts if I did my figuring correct. A bit more than eating a sandwich. at 30 secs that is 42 hrs! A bunch of time in some cases.
Some say having a folding/feathering prop is not worth the expense, because they are cruising. I would say .5-.75 kph is also something to think about, as that is an extra 12-18 miles per day! Potentially as much as 24 for some boats. Again, over a 2000 mile stretch, that adds up to a day or two getting there sooner, less food etc to pack, potentially out running a storm or equal, reality is quite unlikely!
In our local race fleet, we have three of us with 28'ish foot on deck boats, my Jeanneau Arcadia, Cal T2, and a catalina 28 mk II. All have simalar hull deminsions. The C28 a shoal keel at 4' the T2's are ar 4.5, my Arcadia is 5.5'. WHen we have things going right, we can out point the T2's by 3-5*, the T2's out point the C28 by 3-5* also. Hence in this size boat, setups, why there is a 20 some odd sec spread in the boat ratings.
I guess if you do not care how long it takes to get somewhere, then the deep draft vs shoal is not an issue....... In my mind, if a person can afford an Oyster new, assuming the OP is buying a new one, I would swag Oyster would be willing to modify that boat with a dagger board frankly at a 5-10% max cost increase, so for me, well worth it to get the best of both worlds!
She drives me boat,
I drives me dinghy!