Modify rudder to fit OB?

[Peter Hine]

My 27 is an OB model. I just bought a new Johnson 15HP LS 2 stroke, which fits in the well with only a little modifcation. However, in order to avoid the lower unit hitting the rudder when under power, I've had to tilt the OB up to position #3 on the tilt adjust. This causes the OB to push the stern down when at high throttle, the lazarette fills w/water, and the motor's powerhead sits right at water level on the stern wave. I'm considering cutting a notch in the rudder to allow it to miss the lower unit at a more "full down" tilt setting. Anybody done this? Any problems? Is there a better way? (And no, I'm not going to use a transom bracket!)

 

[Joe]

Some thoughts.........

Try putting a 2x8 block between motor bracket and transom. This will effectively move the entire motor out an inch or two and provide additional clearance. Use a shim to mount the motor a bit higher for more clearance. If necessary you can enlarge the opening upward a bit without affecting the hatch cover's operation.The transom may be flexing during power surges, thus affecting clearance. The aforementioned block or a thinner stainless plate will reinforce it.

 

[Joe]

Don't modify rudder.....

....without first checking with Catalina customer service (David Groh). Why? Besides affecting boat performance you may ruin the rudder, and now you're talking big bucks to replace. They may also have some possible solutions to your problem. One other comment... Consider not running at full throttle. The boat will not travel much faster that 6 kts under power, no matter how much horsepower you have. I have a 9.9 hp on my 27, I never use full throttle. Also you might send crew forward to get some weight off the stern end of the boat for better balance.

 

[pass@fcgnetworks.net]

We are on the same wave length.

I bought the same motor and did the same thing you did. I don't run my motor at full throttle since the hull speed is only 6.5 knots anyway. I have my motor tilted too. The wooden block Idea sounds the best. Since the motor only nicks the rudder. I went smimming and watched what was happening. iF the out board sits another 1.5 - 2 "s out away from the stern. It will never hit the rudder. The block of wood will also give more support to the well. As you may have noticed. The well support for the motor isn't very sturdy. I am going to use the block of wood. Pressure treated of corse. I do love my 15 Hp Johnson. Does any one know if they make a kit so I can hook up the cockpit controls to it?

 

[Peter Hine]

OB remote controls

I use a Morse MV-2 control (about $300 from Boat US) in the cockpit, connected to the Johnson 15 2 stroke OB . It connects with 2 std. 3300 cables, about 7-8ft long, one for shift and one for throttle. IS MUCH EASIER THAN THE REGULAR TWIST THROTTLE AND REGULAR SHIFT. Just as convenient as an inboard, w/o using the space, the cost, or complexity. Takes some adaptors available from your OMC dealer ($30) to convert the 3300 cables to the OMC fittings. Everything happens from the cockpit!! And if the motor needs work, you pull it out (about 1/2 hour) and take it to the OB shop!!