Thud from below!

[Pete17844]

I'm looking for suggestions on what might cause a thud from underneath (I'm positive we weren't aground) when taking a wave off the beam in next to no wind. We used to have an O'Day 20' with a centerboard you could raise and lower. It sounds similar to when that used to knock back and forth as we rocked.

I want to say I felt the wheel move a little if we were bounced enough which points me towards rudder, but I'm not entirely certain and it doesn't always happen with the sound. Interestingly enough, it doesn't happen when we take waves head on or off the stern, just when it's off the beam and they're strong enough to shift her a little.

I'd really prefer not to have the rudder drop off so if this a sign of something serious, please say so. I thought I might check with the experts here first before I schedule a hallout one month before she'll get pulled anyway.

Thanks.

 

[Rick D]

Quarter Slap?

If you are referring to a swell off the beam quarter, I get a bit of a 'thump' too. And I can feel it in the rudder. From what you are describing it sounds similar and normal. However, you can always dive and check the rudder play, or if you don't want to do that until your haul, take off the cover and check it from the quadrant side. Check your steering cable tension and lube the sheaves and cable if you go that way. Rick D

 

[Ken Palmer]

Wave slap?

I also have a 33.5 and know that it is certainly noisy dock-side to have a wave slap under the swim platform. You say there was very light wind and no waves. Were you sailing or motoring? Is it possible a power boat passed by leaving a wake?

Did you check your bilge for water? I would also be concerned about the keel and suggest you dive on the boat to check it, or haul it (where the keel will hang) and check for any play.

 

[jtm]

thud in the water

in my case , on my first year with the 28.5 (mid '80's) the thud I heard/felt was eventiually discovered.I remember when it happened I had looked around- perhaps a board or RR tie? and was looking for some debris in the water but saw nothing.

At the end of the day's sail about 40-50 miles from home port, I was in the water floating around the boat and noticed that the rudder looked strange - although painted blue it looked white-ish. I swam up to it and felt around it- Half the rudder, the left side, had separated and must have floated away. check your rudder!