Monday, December 29, 2014

Dripless shaft seal leaks

After driving my boat, I noticed some water in the compartments under the dripless drive shaft seals. In order to get a better idea of what was going on, I monitored the seals while the main engines were run at different RPM settings. At lower RPMs, I saw small bits of water spurting from the seals periodically. At higher RPM, water actually sprayed from the port seal. That's not good! (click for video) I tried tightening the tension of the springs by loosening the set screws on the carbon ring and sliding the ring toward the back of the boat. This helped some, but there was still some water leaking at higher RPMs. Of course dripless seals are not supposed to drip any water. At this point, the next step would be to try cleaning/sanding the seal's carbon flange and rotor, but since I was planning to haul the boat out for bottom paint soon, I decided to wait until then to do any further work on the seals. I'm not crazy about having water gush into the boat while cleaning the flanges. (When inspecting the seals after the haul out, I found that considerable work would need to be done to clean them, with no guarantees that they wouldn't leak afterwards. Also, the springs were nearly worn out. So, I decided to replace the seals.)

Jim Geier
Cheoy Lee Trawler 55