Mod 3 centerboard and new sails.

Thread starter #1
Hi All,

I remember something from the old forum on the subject of centerboards for mod 3s being off?

My centerboard vibrates quite a bit going upwind unless I raise it slightly and then it only vibrate a little. I wonder if this is slowing me down.

Also, I just got new racing sails and I don't seem to be able to point as well as some of the other guys with older sails. Is this also related to my centerboard or do I just need to break in my sails?

Ed Jones

Secretary/Vice Commodore
Centerboard for Mod 3

Jack - Having a vibrating centerboard will definitely slow you up. Some Mod 3s built between 1995 and 1999 had centerboards that were too skinny for the new deck molds that Catalina started using in 1995. (This problem has been corrected on the newer boats.) We had 4 boats in Fleet 2 (hull numbers 4693, 4803, 4804, and 4828) that had this problem. We've since gotten new boards from the factory that have fixed the problem. Jack, you have my phone number, call me for more details.


vibrating CB

Hello Jack
I have one of the boats that Ed Jones mentioned in his previous response. My boat is a Mod 3 (hull number 4804). Ed can tell you all of the details about how we came about fixing the problem on the four newer mod 3 boats at Mission Bay Yacht Club in San Diego. The bottom line is this.....we each had to get a new CB from the factory that was thicker in the top section that stays in the CB well or slot. It seems that the factory changed the size of the CB slot when they designed the new deck molds in 1998-99. The mod 3 boats all have a CB slot which is 1.5 inches wide. However, for first such Mod 3 boats off the line for who knows how long, they were putting the older 3/4 inch thick CBs in the 1.5 wide slot. This causes the CB to become a baffle and causes turbulance, at best. When going upwind, the board actually acted as the reverse of a so-called "gybing centerboard" like those used on the would actually point the boat down lower. The only way that I could get the old skinny CB to behave well in the wider CB slot was to get two thin 6 inch long flexible ash wood shims and push one down either side of the after edge of the CB when it was in the down position. This would change the performance of the CB to that of a gybing CB. The gybing CB actually causes the boat to point 4 degrees higher when the leading edge is forced over to the upwind side by the force of lateral resistance. You can find all about gybing CBs on the 505 home page or just type in "gybing centerboard" in one of the better search is sometimes spelled differently....."jibing centerboard".

As soon as I dropped the new fatter CB into the slot of my mod 3 boat, it pointed higher and better. I have also raced against another such boat that had the very same problem and one of the ones we corrected (#4803). This boat is sail by firends of Ed and I..... by Larry & Sally Lyons. Before the new CB was dropped into his boat, he never NEVER was able to climb over me on a windward tack. Now that his boat has the new board, he is able to point so much higher and climb over me if he has the lead, at all. Getting the fatter or thicker CB may be answer to your problem. However, you can try the trick with the shims, first, if you do not want to make any structural changes.

best regards,

Brian C. Anderson
C-14.2 Fleet Captain
MBYC, San Diego, CA



Thanks for the info Ed and Brian. My boat is #4964 which is right after one of the boats you mention. I've noticed that I've never been able to point as high as the older boats in our fleet and I think I only did well at nationals on the very windy days with my heavy crew!!

I don't have Ed's number but I'd like to call him. My email is mccollumj and add to the end.

Hi all, I have C14 # 4809 and I have the skinny CB. I live in Cairo Egypt and just bought this boat used from the states and got it shipped over. Cost me a lot of money but I love the boat. I'm pretty sure getting the correct CB will not be feasible cost wise. Do u think the skinny CB may also be the reason water gushes in through the CB slot or replacing the gasket would just fix it.