Do sterndrives (bellows) sink boats?

Discussion in 'Powerboats' started by Tim.M, Apr 17, 2009.

  1. Tim.M
    Joined: Apr 2009
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    Location: Wisconsin

    Tim.M Junior Member

    How much bilge pump capacity is a good balance in a 25' to 30' hull? (with two batteries and two mercruiser 350 alternators to provide power)
     
  2. engineer@sg
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    engineer@sg New Member

    I am a sterndrive dealer but I have not seen a split bellow sinking a boat yet. Normally u might have a little leak into the engine bilge area but not enough to sink your boat unless you havent been to your boat for the last 1 year or so. You shouldnt worry and if you got good maintenance plans, such things never happen.
     
  3. PAR
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    PAR Yacht Designer/Builder

    Again, the statistics clearly show the percentage of sinkings on I/O equipped craft. It's not a made up figure, it's simply fact. You can elect to believe these figures or stick your head in the sand and hope it will not happen to you.

    Maintenance of course is the key, but lets face it, routine maintenance isn't preformed on the vast majority of small craft. This is the reality of small craft ownership in the last few decades and keeps repair shops in business.
     
  4. Boston

    Boston Previous Member

    Ill take your word for it Par
    so whats the lowest failure rate inboard engine set up
     
  5. engineer@sg
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    engineer@sg New Member

    Sterndrive Sinking boat

    Hello PAR,

    If you want to put it in this analogy, then even shaft driven boats will sink because the shaft seal won't be maintained. Outboard boats will sink also because there might be a plastic bung at the lower bilge that needs to be replaced every few years or so. So, all in all, it does boil down to maintenance. If the owner doesnt give a crap to his boat, he deserves to sink.

    I have a boat building shop too, and we build all our boats totally foam filled and unsinkable. So, I guess for lazy owners, they just have to get one of our boats :D
     
  6. PAR
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    PAR Yacht Designer/Builder

    I don't think anyone "deserves" to sink. We agree in that routine maintenance is the key to keeping a boat and something that isn't preformed as it should.

    The statistics separate through hulls from stuffing boxes, from drive units, etc.
     
  7. Tim.M
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    Tim.M Junior Member

    It's also a question of how easy it is to maintain something. Is it easier to maintain a stuffing box seal or pull off an outdrive to replace the bellows yourself? Or are both a piece of cake once you've done it a few times?
     
  8. CDK
    Joined: Aug 2007
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    CDK retired engineer

    My 27ft cruiser was equipped with twin Mercs. We came back from our annual holidays in the Meds and brought the boat by truck to the marina. One day I got a call from the marina that my boat was sinking.
    When I arrived both engines were submerged up to the carbs. All electrics beyond repair due to electrolysis.
    The boat was hoisted out immediately and the insurance experts were called.
    They found a small cut in the port bellows, caused by an oyster lodged in a corner of the gimbal housing. Looked quite harmless but it wasn't.
    The leakage must have started with just a few drops, but once the boat gets deeper in the water, the process accelerates. In my case the boat was left unattended for only a month.
     
  9. Boston

    Boston Previous Member

    so once again
    what is the least problematic inboard configuration
    if 70% are due to that particular type of drive
     
  10. fasteddy106
    Joined: Apr 2009
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    fasteddy106 Junior Member

    I can't concieve of letting my boat sit for a month without taking a look at it. I'm paranoid that way. Tim, there are millions of boats out there with I/O setups that don't sink. Just pay attention to the common sense stuff. Make sure your batteries are in good shape. If you have shore power and are allowed, keep your battery maintainers plugged in or get solar maintainers. When you leave the boat for the week, make the last thing you do a check of the bilge pump to be sure it operates correctly. Be sure to keep aquatic growth cleaned off the outdrive boot with a soft bristle brush. Make sure your boat is secured to the dock correctly and the outdrive wont beat itself to death against it. Check your lines, if they are chaffed, replace them. It's when boat owners get lackadaisical and start to think, "That can't happen", that disaster strikes. Make yourself a check list and go over it religiously when you leave the boat. For that matter, have a check list for when you get on the boat after an absence. Write down problems you find and attend to them immediately. Taking care of little stuff prevents big stuff and keeps you out of the dry dock, you don't get to know the SeaTow captain real well, and you avoid the "Gee thats a shame" speeches from your marina buddies.
     
  11. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Again 70% of all I/O equipped sinking were a result of a leaking bellow.

    No they're not hard to change if you've got some experience with I/O's. If not, you'll cuss a lot the first time. For most drives a "transom kit" which typically includes bellows, O rings, gaskets, etc. to make things good again can be had for less then 100 buck (okay maybe not full retail).

    Fasteddy is right, if you boat is on a hook or at a berth, don't leave it unprotected or unattended for long. Where I live a few weeks of summer rain can easily overwhelm a small bilge pump.

    Most marinas will keep an eye on LWL's or boot stripes. They can't catch them all before the engines sunk up the wet stuff, but they also don't want a bunch of oil and goo floating around their docks either. You'll pay dearly for this if you force them to climb aboard and install a "real" pump.

    If you treated your wife like most treat their boats, you'd be lonely pretty quickly.

    If you take care of them, you generally don't get these types of surprises.
     
  12. CDK
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    CDK retired engineer

    Stern drives are no problem as long as you pull the boat out after use.
    I was in Venice last week, where Mercuisers have largely replaced the Gondolieri who are not allowed to sing anymore. Because Venice is a 12 month a year tourist attraction, they have no time to scrub, inspect or replace anything in the water.
    In the small harbors around Venice I saw unbelievable piles of scrapped Merc I/O's. The Volvo Penta's were much much fewer and always very old models.
     
  13. mark775

    mark775 Guest

    Not that it directly applies but be aware that vandalism can occur... A guess here...maybe thirty(?) years ago in Tacoma (near Seattle) at, I think, Day Island Marina, some demented soul put on a wet-suit and knifed every I/O bellows in the marina. I hope he doesn't do that again...
     
  14. CDK
    Joined: Aug 2007
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    CDK retired engineer

    I think it does apply!
    Using a sterndrive means that the only thing between you and the sea is a thin layer of rubber, held in place with some glue and a hose-clamp. Every mechanical engineer will agree that is asking for trouble. What an idiot with a knife can do, can and will also be done by a sharp shell or other sea creature.

    For several years already, the sales figures of sterndrives are dropping slowly, the market is shifting towards 4 stroke outboards.
     

  15. Boston

    Boston Previous Member

    you can only take care of em for so long after that you should make a trade in

    analogy works well for both boats and woman :D
     
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