I'm considering notching the front of the rudder to make additional clearance for a 4 stroke yamaha outboard. The 1975 boat may have the original rudder that shows up in the attached design drawing. The swept back rudder extends well back behind the stern. Not sure what the boat designers were thinking of in 1975 with respect to a motor...inboard engine only, or short shaft only, or motor bracket? I am aware of the Booth Rudder, and bracket, and cutting the top side options. Does anyone have experience with notching the trailing edge of a rudder on a Catalina 27? I have heard that the rudders are fiberglas and are filled with foam and that normal fiber glass will melt the foam so one needs to use some other type of patching material.
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Did at last haul
Three years ago, at my last haulout, I had the yard notch the aft end of the rudder about 2" to clear the outboard. I don't know what resin they used, but I'd expect it was epoxy, as that is the norm now. Epoxy resins like West Systems (unlike the original polyester) has no effect on foam. Polyester is old technology.
Three years ago, at my last haulout, I had the yard notch the aft end of the rudder about 2" to clear the outboard. I don't know what resin they used, but I'd expect it was epoxy, as that is the norm now. Epoxy resins like West Systems (unlike the original polyester) has no effect on foam. Polyester is old technology.
did that to my cat 27 '75 a few years ago
Yea, I did that for the same reason a few years ago. We put a v shaped notch in where the motor hit. Used normal epoxy. More important though was adding an aluminum lip where the motor mounts in the well. Some of the problem comes from the flex in the well when you increase power.
Yea, I did that for the same reason a few years ago. We put a v shaped notch in where the motor hit. Used normal epoxy. More important though was adding an aluminum lip where the motor mounts in the well. Some of the problem comes from the flex in the well when you increase power.
Rudder notch
Since there are literally over a thousand outboard C27s running around out there without an owner-chopped-up rudder, I don't really think it was a design flaw on Catalina's part. Most owners have no problem with either long or short shaft motors and stock rudders. The hint about reinforcing the transom is valid, and putting the reinforcement on the outside of the hull would also move the motor back a fraction of an inch. An even simpler idea might be to look at your motor tilt angle. All outboards have some sort of adjustment for fore and aft tilt from the vertical; the C27 transom slopes inward, and if your motor is not adjusted for that, it will as well. Move yours one click back and see if this works. I would most definitely play with motor adjustment before hacking away at the rudder.
Since there are literally over a thousand outboard C27s running around out there without an owner-chopped-up rudder, I don't really think it was a design flaw on Catalina's part. Most owners have no problem with either long or short shaft motors and stock rudders. The hint about reinforcing the transom is valid, and putting the reinforcement on the outside of the hull would also move the motor back a fraction of an inch. An even simpler idea might be to look at your motor tilt angle. All outboards have some sort of adjustment for fore and aft tilt from the vertical; the C27 transom slopes inward, and if your motor is not adjusted for that, it will as well. Move yours one click back and see if this works. I would most definitely play with motor adjustment before hacking away at the rudder.
Bang on jimg!
I have a 74 Cat 27 with the motor well and a 9.9 Mrec. At first, I had a few nicks, but by readjusting the motor angle, it cleared right up! There was no loss in performance at all. Now, if I could just find an inexpensive way to resolve the fact that the 4 stroke doesn’t tilt into the well, I’d be a happy camper! Later, eh! Ferg
I have a 74 Cat 27 with the motor well and a 9.9 Mrec. At first, I had a few nicks, but by readjusting the motor angle, it cleared right up! There was no loss in performance at all. Now, if I could just find an inexpensive way to resolve the fact that the 4 stroke doesn’t tilt into the well, I’d be a happy camper! Later, eh! Ferg
Update: Motor Tilt Alone Does Not Work
I appreciate the comments from everyone. When I bought the boat it had a 1985 long shaft 9.8 Merc installed with a 1 inch high piece of wood bolted on top of the motor mount. The combination of motor tilt and the wood allowed the the bottom end of the motor to clear the rudder. The old Merc has more tilt holes than the new Yam. I could not just exchange the motors on the boat because the 4 stroke extends upward higher when motor is in the tilt up position. The introduction of the very popular and larger 4 stroke outboards has made the 1975 vintage Catalina 27 motor mount design obsolete and the boat requires modifications of some kind. I have seen at least 7 different Cat 27s with 4 strokes installed and they were all modified in some way. Some have added brackets at the back. Rudders have been changed or were different from mine when new, holes have been cut in the top of the motor compartment and stern. A high cut may require going from a single to double back stay. One owner I met had cut his motor mount lower to accept a 8 HP Yam HT and said he was happy with it. A couple of owners just left the holes so the tops of the motors protruded no more than 1 inch above the lid. Others have modified the covers, either by raising the entire cover, or by adding a raised portion to the back of the cover to conceal the holes that were cut. And as we have heard here..some have cut notches in the rudder as well. I also heard of one owner who just leaves the 4 stroke in the down position. Since my first post, I contacted Catalina and they e-mailed me a sketch they had that shows a wooden shim under the exterior of the motor mount and a notch in the back of the rudder. I heard about the sketch from this forum archive. On the phone they also mentioned the motor bracket option. I like the original Catalina motor well design concept and I am trying to preserve it as much as I can. I think the entire boat is a great design. I have removed the 1 inch wooden block and cut down the motor mount by 3/4 of an inch and the 2006 Yamaha ELH 9.9 HT just fits "under the lid". With full mimimum tilt set on the motor the motor will not pass the rudder above about 2 knots. I then added a 1/2 inch plywood shim that gave me about a hand's thickness clearance "at the dock". This helped but at about 3-4 knots (forgot to take the GPS) the rudder was just clipping by the motor. I have now made up a tapered 3/8 to 3/4 inch plywood shim and will test it to see if this works. this shim gives me about 2-3 inches of clearance "at the dock" (hard to measure under water). I will test it soon.
I appreciate the comments from everyone. When I bought the boat it had a 1985 long shaft 9.8 Merc installed with a 1 inch high piece of wood bolted on top of the motor mount. The combination of motor tilt and the wood allowed the the bottom end of the motor to clear the rudder. The old Merc has more tilt holes than the new Yam. I could not just exchange the motors on the boat because the 4 stroke extends upward higher when motor is in the tilt up position. The introduction of the very popular and larger 4 stroke outboards has made the 1975 vintage Catalina 27 motor mount design obsolete and the boat requires modifications of some kind. I have seen at least 7 different Cat 27s with 4 strokes installed and they were all modified in some way. Some have added brackets at the back. Rudders have been changed or were different from mine when new, holes have been cut in the top of the motor compartment and stern. A high cut may require going from a single to double back stay. One owner I met had cut his motor mount lower to accept a 8 HP Yam HT and said he was happy with it. A couple of owners just left the holes so the tops of the motors protruded no more than 1 inch above the lid. Others have modified the covers, either by raising the entire cover, or by adding a raised portion to the back of the cover to conceal the holes that were cut. And as we have heard here..some have cut notches in the rudder as well. I also heard of one owner who just leaves the 4 stroke in the down position. Since my first post, I contacted Catalina and they e-mailed me a sketch they had that shows a wooden shim under the exterior of the motor mount and a notch in the back of the rudder. I heard about the sketch from this forum archive. On the phone they also mentioned the motor bracket option. I like the original Catalina motor well design concept and I am trying to preserve it as much as I can. I think the entire boat is a great design. I have removed the 1 inch wooden block and cut down the motor mount by 3/4 of an inch and the 2006 Yamaha ELH 9.9 HT just fits "under the lid". With full mimimum tilt set on the motor the motor will not pass the rudder above about 2 knots. I then added a 1/2 inch plywood shim that gave me about a hand's thickness clearance "at the dock". This helped but at about 3-4 knots (forgot to take the GPS) the rudder was just clipping by the motor. I have now made up a tapered 3/8 to 3/4 inch plywood shim and will test it to see if this works. this shim gives me about 2-3 inches of clearance "at the dock" (hard to measure under water). I will test it soon.
Um, Glen ....
The guy who leaves the motor down would be me. As I’ve said before, it costs about a knot, but I don’t race my boat anyway. There are good fixes, most are costly, I refer you to rsn48 who did a great job of fixing this problem. Consider as well, some 4 strokes will leak oil when you are heeled and the motor is tilted up. Check your owner’s manual, it’ll tell you what side the motor SHOULD’NT lay on. Later, eh! Ferg
The guy who leaves the motor down would be me. As I’ve said before, it costs about a knot, but I don’t race my boat anyway. There are good fixes, most are costly, I refer you to rsn48 who did a great job of fixing this problem. Consider as well, some 4 strokes will leak oil when you are heeled and the motor is tilted up. Check your owner’s manual, it’ll tell you what side the motor SHOULD’NT lay on. Later, eh! Ferg
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