Join Date: May 2002
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Barnacles have two significant effects on a sailboat. They create a tremendous amount of drag, which prevents the boat from gaining speed, and they disrupt the smooth flow of water over the keel, rudder and hull, which makes the boat difficult to control.
The barnacles on the hull and other surfaces create so much drag that the boat can't get up to speed. Without speed, a sailboat can't sail close to the wind. Without speed, the effects of the rudder and keel are reduced. The boat's performance will become, at the very least, sluggish, and at the worst, uncontrollable. It also can't tack to windward, because, when you put the helm over and the sails start to luff, the boat has to continue coasting through the turn until the bow crosses the wind and the wind fills your sails on the opposite tack. But, because of all the drag created by the barnacles, the boat won't coast far enough to bring its bow across the wind. It just coasts to a stop.
The keel enables the boat to sail to windward. Water flowing smoothly over its surface creates lift, and it resists the lateral drift of the boat. Barnacles on the keel not only disrupt that smooth flow of water that makes the keel work, but they also create drag, which retards the boat's speed and prevents it from coasting, as explained in the above paragraph.
You say that you have scraped the barnacles off the hull and rudder, and that you now only have barnacles on the keel. But, my guess is that, even though you have scraped the barnacles off those surfaces, they're still pretty rough, and are still creating a lot of speed-robbing drag. I can only guess, but I suspect that the barnacles on the keel and the remaining roughness on the hull and rudder are still going to make the boat extremely sluggish, and perhaps uncontrollable, under sail.
If you can scrape the barnacles off the keel, that might be enough to permit it to sail, sort of, but it's not going to sail very satisfactorily until you pull the boat out and do a proper bottom job.
I suggest you mount a motor on the boat, or have a friend help you tow it, to a place where you can pull it out and do a bottom job on it.
The good news is that the Cal 25 sails nicely and is a lot of fun to sail, so, if the boat is fundamentally sound, it should be well worth the effort.