For the past several weeks we have kept the boat at our Yacht Club on the North Channel of the St. Clair River whilst closing the club for the winter. This is a working club where the members perform 99% of the club maintenance, club operation and function. Anyway, "Bella" has been docked at the club and Donna and I have come and gone throughout this period to work and such. During this time the engines have not been started.
Yesterday we completed the close down of the club and prepared to head home. So, we power up and cast off to head to our permanent well at Mac and Rays Marina. Once clear of the No Wake, I throttle up the 6V92's but the Starboard side engine would not advance past 1100 rpms. My first thought was a clogged fuel filter and since our Marina was only 5 miles away we decided to just idle home. Afterall, it was mid 60's and sunny. Donna and I are enjoying the view and the relatively flat lake when we smell a peculiar odor, one that smells like melting plastic. She takes the helm and I begin the search for this strange odor. There is no smoke anywhere, but it is pronouncely stronger at the stern. The gauges indicate no problem.
Not believing in coincidences, I figure this smell has to be linked to the starboard engine anomaly. My next decision is one that is learned at Man School, Course 101. If something is stuck or stubborn apply power until it is freed. So, I throttle up the starboard enging, kind of gassing it. Hugh clouds of black smoke come from the exhaust, when suddenly in a burst/blast/belch a large clot of material flew out into the water and the engine rev'd to 2000. A couple more rev's produced additional crap. It was hard to tell exactly what the material was, but there was some weeds and thatch clinging to the exhaust after the expulsion of the initial mass.
A minute or so later we are on plane and I am checking the gauges, all is well. We are crusing thru our range from 18 to 27 and back to our normal 20. Donna takes the helm and I check all bilges and compartments to assure we have no unseen damage, when I spot on the outboard side of the starboard engine a large water leak coming from the exhaust gasket. The water is coming in fairly quickly, but the bilges seemed to be keeping it from rising, so we continue on to the marina where we tie up. After securing "Bella" to the dock and making fast, we begin our unloading procedure. For approximately 30 minutes the bilge pumps continue to pump out water. Upon inspection of the gasket I notice water is draining and I assume this is the captured water in the "system" being drained by gravity into the bilge.
I spoke to a couple of friends about this incident and we conclude that there must have been some critter, say Muskrat, that had begun to build a nest in the exhaust tube. It clogged the engine preventing the exhaust from operating at capacity. The pressure must have built to the point the clog finally gave way. My friends also suggested that the gaskets be replaced as they are rubber and Muskrats have been known to eat them. Today, I intend to cram my fat butt into the outboard side of that engine and do a thourough inspection.
We've had a problem around the ranch with ground squirrels. For a while, we were concerned they were communicating, and plotting to over-run the place.
This is a new one on me! Glad it didn't do any permanent damage. Perhaps you should get some plugs made, spring loaded that snap in and hold tight, with a cord so you can pull em off?
At first blush, it may seem funny, but muskrats have sunk plenty of boats. Big ones and small ones. On a large boat, they like to crawl up the exhaust and chew through the rubber exhaust hose. They also have a fondness for the rubber diaphrams used on some I/O's causing leaks. Something to be aware of - Your insurance may not cover vermin induced damage. - Ouch! There are screens to cover your exhaust ports available for precisely this reason.
I kept my Tollycraft about 200 yards from the Seattle Yacht Club directly across portage bay and about the same time the critter in the article above sank that boat. He chewed through both my trim tab hoses. Easy fix though... I just pulled the slack on the hose, reconnected and I was back in business.
Darn Critter's Buggin!
Jim
69 24' Tollycraft Royal Express Cruiser (Previous boat)
74 36' Chris Craft Sports Cruiser
Seattle
I managed to wedge myself outside of my starboard engine in an effort to determine the extent of damage caused by the Muskrat. The good news is that there is no physical/observable damage to the rubber exhaust connector, however, I did discover two of the hose clamps were loose allowing water from the discharge side to come into the bilge. Once tightened this seemed to cure the issue. The bad news is there is no physical/observable damage to the exhaust connector. Meaning I cannot determine internal sidewall damage without removing the connector. Furthermore, I discover that my exhaust system has 3 such connectors between the exhaust manifold and the exhaust port. The critter could have been in all three.
In lieu of dissassembly, which will require the removal of one 125 gallon water tank, my thought is to find a flexible extendable camera-light. The extension needs to have about 20 feet of neck to see all three connectors. With this I should be able to determine the extent of any damage and or wear. Any other suggestions?
On another note, the sound level of my engines is a bit loud for my tastes. With the hardtop, the sound seems to get amplified. Does anyone know if the mufflers could be changed out or additional baffle added? If I need to dissassemble the exhaust piping, I might as well dampen the sound while I am at it.
Terry:
Check out Harco Manufacturing www.harcomanufacturing.com
They have produced HAPCO exhaust silencers for the Navy and Coast Guard, as well as the general public.
Talk to Frank Harris @ 1-800-394-7571
Terry, I do not think a camera is going to give you the full picture (so to speak) of the condition of your exhaust connectors. The best and safest way to do this job, is by dissasembly and visual inspection. The bad part is that these connectors are often on there pretty tight, in which case it is better to cut them off rather than risk damage to the exhaust pipes. A frend of mine has a 1980 45 TF with 6V92TA's in it. He just went through replacing both long fiberglass pipes that lead from the engine room to the muffler. (You are right, the water tank has to be removed.) His were cracked. Remember, one hell of a lot of water goes through those pipes. If there is a failure? Well, you get the picture. While you are down there, check the exhaust side of the turbos to make sure they are spinning freely and have no evidence of water damage.
As for the exhaust, I found on another forum (Boatdiesel.com) that a guy replaced the mufflers on his 671TIB,s with new Veritones. He reported that it reduced the sound level pretty much and did not have any effect on his engines.
I've got a couple guys from the Club coming over to the boathouse on Sunday. We are bringing the sewer camera and will begin there. If satisfactory visual confirmation can be obtained and I feel confident of the condition, then I will leave it at that. If we cannot get a decent view, then we are prepared to remove the connectors and replace.
I really believe that the critter had just begun to make its nest and had contained itself abaft of the engine room bulkhead. My reasoning for this is the connector just inside the engine room compartment had loose hose clamps most likely caused by back pressure. In that case, the connector adjacent to the water tank is the most likely one to have been damaged, if any.
I will do some research on the mufflers you mentioned and will report back on the findings of Sunday's surgery.
