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Thread: Who's running an Arneson or Yanmar drive?

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    Member smtdvm's Avatar
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    Default Who's running an Arneson or Yanmar drive?

    I am looking at various options for ridding myself of my unreliable Bravo II Diesel stern drive. Options include reconfiguring to surface piercing, outboard, Konrad or Yanmar drive. Of course cost is an issue with all options. Building a stern pod and hanging a 350 OB on would likely be the most initial cost as well as result in lost fuel economy and range but I also understand that this can be a pay know or later situation and that fuel might be the cheapest part of boat ownership in the long haul. Anyway, not looking for a beating over IB, OB, gas, diesel, twin or single. Seen and heard all that before. I like my boat a lot but it needs to be safe and reliable. A few details; 27' custom alloy , Yanmar 315 hp diesel, coastal cruiser, about 9k# ready, 6.5 gallons per hour at cruise, 150 gallon tank, cruise about 22knts @ 3200 rpm, WOT 3800rpm at 29knts. Not on my list are rebuild or replacement of the Bravo or a Volvo.

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    Member Sobie2's Avatar
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    Holy one thing I remember about the advertising of the Alaska 27 was the reliability. Sorry to hear about your drive problems. Your boat is a big boat. One thing if I was running a mercruiser drive would be to have installed a drive shower to cool it off. Those are only about $150. Also you have to baby those things with slow acceleration and coming off step. Most folks believe that big 27'-30' planing hulls are at that range were single stern drives are pushed to the max. I know here in Juneau that our steep narrow seas are especially tough on outdrives as you climb up and down the seas.

    Boattest.com has a write up and video review of the Yanmar drive and that may give you some insight. It seems to be the best first option since you already have it set up for an i/o and that you have Yanmar engine. Probably the least expensive too of the list you are considering.

    Next best would be going the outboard route. I'd suggest twins, a lot of people here in Juneau have done that lately and man as a recreational user, whale watch, and charter guys all going outboard that says a lot. Very easy on the maintenance and you don't really winterize them here (yea all the businesses are running outboards here, some repair and maintenance bills on diesels are thousands compared to a few hundred on outboards). Darren at Broken Rudder has done a lot of these and Harri Welding is doing good work too. Good work and good prices from both shops, then drive it over to some other shop on Industrial for your choice of power. Your boat is already kind of Yamaha blue in color and twin 150s up to twin 350s would be sweet. But heck we see a lot of Mercury motors in the charter/whale watch fleets and the new Merc 150 four stroke seems to be really durable and reliable with the oversize gear case, and we know the Hondas are great too. All of those will be zero down time, more thirsty but probably you will get cruise speed in the 30s. Your old engine space will need to be filled with more fuel capacity.

    If it were my boat I would really have to find some compelling reasons to not go for the Yanmar drive because it seems like the obvious choice (should be an easy change over, same configuration, same fuel economy) given that you are determined to chuck the Bravo II. As a final note talk to the builder designer. I seem to recall that fuel economy was a selling point for the Alaska 27.

    Let us know what you end up doing!

    Sobie2

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    Member smtdvm's Avatar
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    Thanks for the input Sobie2. Most of your thoughts echo my own. The modern outboards are pretty hard to beat and that would be my first choice if I was doing a new build or buy. I am thinking hard on the Yanmar, given that it should be a fairly simple replacement but I want to do my homework to prevent a repeat situation. Dockside Machine is now using the Yanmar drive on the AK27s . In fact, mine was the last one with a Bravo. I am in touch with the builder fairly often and pinged him for updates on their reliability. The AK27 has been amazingly reliable, the only failure of anything in the six years I've had her has been the drive. Not as much as a wire short, crack, or breakage of any kind to the boat itself. He actually does build them himself, one boat at a time. From the time I bought it, I pretty much expected problems with the drive so it's not unexpected and I have been planning on doing something different at the next failure so here I am. It will be later in the winter before I have any time to get moving on anything but I'll post what I end up doing.

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    Member Akgramps's Avatar
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    Nice looking craft, if you switch to the Yanmar drive, I assume you could use the Yanmar motor you already have......?
    “Nothing worth doing is easy”
    TR

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    Member smtdvm's Avatar
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    Quote Originally Posted by Akgramps View Post
    Nice looking craft, if you switch to the Yanmar drive, I assume you could use the Yanmar motor you already have......?
    Yes. Infact that is usually how they package a new setup now. They also make a Bravo replacement setup that utilizes the Bravo holes in the transom.

  6. #6

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    Quote Originally Posted by smtdvm View Post
    I am looking at various options for ridding myself of my unreliable Bravo II Diesel stern drive. Options include reconfiguring to surface piercing, outboard, Konrad or Yanmar drive. Of course cost is an issue with all options. Building a stern pod and hanging a 350 OB on would likely be the most initial cost as well as result in lost fuel economy and range but I also understand that this can be a pay know or later situation and that fuel might be the cheapest part of boat ownership in the long haul. Anyway, not looking for a beating over IB, OB, gas, diesel, twin or single. Seen and heard all that before. I like my boat a lot but it needs to be safe and reliable. A few details; 27' custom alloy , Yanmar 315 hp diesel, coastal cruiser, about 9k# ready, 6.5 gallons per hour at cruise, 150 gallon tank, cruise about 22knts @ 3200 rpm, WOT 3800rpm at 29knts. Not on my list are rebuild or replacement of the Bravo or a Volvo.
    Just curious as to what issue have you had w the BIi? Are you also running the exhaust thru the drive?

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    Member smtdvm's Avatar
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    I haven't been able to pull the drive yet but it is pretty clear that the failure is catastrophic. Yes, the exhaust exits via the bellows through the drive. Despite frequent oil changes using recommended oil, drive shower, gentle operation, cautious and gradual throttle and shifting, it has failed with 400 hours service since last failure and overhaul. The drive is just not up to the torque of the Yanmar 6LY. Last time it was a tooth broken off of the upper pinion that gravitated throughout the drive. There were no indicators of impending failure this time. Gear oil was recently changed and no evidence of metal or water in the lube, no ominous sounds or vibrations, no collision with flotsum. Just bang, stop. I would expect another failure should I chose to continue with this model drive on this engine/boat combination.

  8. #8

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    Quote Originally Posted by smtdvm View Post
    I haven't been able to pull the drive yet but it is pretty clear that the failure is catastrophic. Yes, the exhaust exits via the bellows through the drive. Despite frequent oil changes using recommended oil, drive shower, gentle operation, cautious and gradual throttle and shifting, it has failed with 400 hours service since last failure and overhaul. The drive is just not up to the torque of the Yanmar 6LY. Last time it was a tooth broken off of the upper pinion that gravitated throughout the drive. There were no indicators of impending failure this time. Gear oil was recently changed and no evidence of metal or water in the lube, no ominous sounds or vibrations, no collision with flotsum. Just bang, stop. I would expect another failure should I chose to continue with this model drive on this engine/boat combination.
    in 11 years of using the BII drives on my charter boat I've never had a catastrophic failure. This year I converted to thru hull exhaust and it made a huge difference in how clear the oil remained between changes even with the larger 25p props and more hp in front of them cruising 31kts. Keeping the exhaust heat out of the drive makes a big difference. I'm wandering if it's possible that you just have the wrong drive ratio for your boat's size and weight. Do you know the weight and drive ratio?

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    Quote Originally Posted by Halibutgrove View Post
    in 11 years of using the BII drives on my charter boat I've never had a catastrophic failure. This year I converted to thru hull exhaust and it made a huge difference in how clear the oil remained between changes even with the larger 25p props and more hp in front of them cruising 31kts. Keeping the exhaust heat out of the drive makes a big difference. I'm wandering if it's possible that you just have the wrong drive ratio for your boat's size and weight. Do you know the weight and drive ratio?
    Its a huge difference pushing a boat with one drive vs twins.

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    Thanks for the info Halibutgrove. Just goes to show, there is a lot of variation in the survival of these things. 11 years of reliable work is impressive. The exhaust heat issue is not something I considered. My drive ratio is 1.81:1. I haven't scaled the boat so I'm guessing about 9k#. I should find the time to weigh it. Twins, as Steve points out would likely share the load better but I'd have to go w OBs to do that and I don't think I'm there yet. God knows though, I'd probably just up and do whatever Potbuilder told me to do just to save being wrong later (standard disclaimer, pending spousal approval). I appreciate you knowledge and experience. It's very helpful.

  11. #11

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    Quote Originally Posted by smtdvm View Post
    Thanks for the info Halibutgrove. Just goes to show, there is a lot of variation in the survival of these things. 11 years of reliable work is impressive. The exhaust heat issue is not something I considered. My drive ratio is 1.81:1. I haven't scaled the boat so I'm guessing about 9k#. I should find the time to weigh it. Twins, as Steve points out would likely share the load better but I'd have to go w OBs to do that and I don't think I'm there yet. God knows though, I'd probably just up and do whatever Potbuilder told me to do just to save being wrong later (standard disclaimer, pending spousal approval). I appreciate you knowledge and experience. It's very helpful.
    I suspected you were running a low ratio drive. The smaller gears don't handle the torque as well as larger gears found in the 2.0:1 drives. You can obtain the same speed by running a large pitch prop with bigger gears in the drive. I'd swap to a 2.0:1 and bigger prop. Run a thru hull exhaust and drive shower and hopefully your already pulling your raw water cooling thru the drive. Should provide years of service with regular oil changes every 100hrs.

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    Quote Originally Posted by smtdvm View Post
    Thanks for the info Halibutgrove. Just goes to show, there is a lot of variation in the survival of these things. 11 years of reliable work is impressive. The exhaust heat issue is not something I considered. My drive ratio is 1.81:1. I haven't scaled the boat so I'm guessing about 9k#. I should find the time to weigh it. Twins, as Steve points out would likely share the load better but I'd have to go w OBs to do that and I don't think I'm there yet. God knows though, I'd probably just up and do whatever Potbuilder told me to do just to save being wrong later (standard disclaimer, pending spousal approval). I appreciate you knowledge and experience. It's very helpful.
    You need a pyrometer on that rig along with running the exhaust out the stern instead of thru the drive. Honestly i'd think biting the bullet and going with outboards might be the best thing for that boat, in my opinion ALL out drives are junk time bombs, some just have longer fuses till they blow ! You don't see many outboard boats that are well maintained on the end of ropes much, those new motors are very dependable. If i was going to get a smaller boat i'd be looking for a outboard boat.

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