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Looking at Post's

Discussion in 'Post Yacht' started by old44272, Oct 26, 2011.

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  1. old44272

    old44272 New Member

    Joined:
    Oct 25, 2011
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    3
    Location:
    North East, MD
    I currently have an Ocean Yachts 29 SS. Love the boat, but possibly looking for something bigger. I really like the mid 80's 42 and 43 Posts. Looked at an 86 43' near me last weekend, (actually sea trialed it) and hope to do the same on a 42' this weekend. I had a couple questions for current owners:

    The boats have Detroit 671 TI's (one is actually a TIB). I never had a diesel boat before, so I started researching these. Internet gooroos (some, but a lot of them anyway) say that these engines are only good for 1500-2500 hours. Is that true to those of you that have them? I spoke to a Detroit Diesel guy at the Annapolis Boat Show and he said that it is typically $3000 a cylinder to overhaul these things. Is that what you guys have found? $36,000 to do 2 engines? I'm looking for real life stories about these engines. Thanks.

    Also, on the 1986 Post 43' with the 671 TIB's, the boat made 16 knots at about 2000 RPM's, and about 20 knots WOT. Seemed a little slow to me from what I had read, and the boat was pretty much empty (no water, low fuel, etc). What are your experiences with RPM and speed?

    And how about fuel burn? No fuel flow meter on board. What's a good estimate on GPH?

    I appreciate your replies. Please don't bash me because I have a little Ocean. LOL! It's a little tender but we love the **** thing! But maybe I'll be a POst owner soon?!:)
  2. RT46

    RT46 Senior Member

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    Feb 22, 2011
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    Location:
    Long Island, NY
    the numbers for the 43 seem slow.
    what is the max RPM WOT load? no load?
    EGT?
    any smoke?


    The 42-43 Post is a very nice boat.


    RT 46
  3. chesapeake46

    chesapeake46 Senior Member

    Joined:
    Jul 26, 2009
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    1,776
    Location:
    Chesapeake Bay, Delaware Bay & S.Jersey
    I've got an '80 46 with 410hp 671's.
    It is a 20 to 22 knot boat.
    I average 25 gals per hr at 2200 RPM including genny.
    We have about 3300 hrs on the engines.
    They smoke when they are started, especially when it's cold out.
    Block heaters would prolly help this issue a great deal.
    They are not the most effecient engines, I'm told, but I have found them to be very dependable.

    They are easy to work on for maintenance stuff and all of the crucial stuff is inboard on each engine.

    If you maintain them and don't beat them, they will last a long time.

    Your #'s do seem low. was the boat clean on the wheels and gear when you ran it ?

    Good luck in your adventure.
  4. 42hatteras

    42hatteras New Member

    Joined:
    Oct 18, 2009
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    Location:
    New London Ct/Hope Town Bahamas
    The bottom and or running gear on the 43 you sea trialed must have been fouled.That boat should have been significantly faster than that,especially with TIB's.My 42 Post with TIB's cruises approximately 21-22knots at 1900 rpms,tide and breeze dependent. The TIB's were not my engine of choice,but run conservatively they will last a decent amount of time.In my opinion as a marine mechanic the aforementioned 410's were the most durable of the high horsepower 671's and would have been my first choice,if I hadn't found a deal I could not pass up.
  5. old44272

    old44272 New Member

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    Oct 25, 2011
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    Location:
    North East, MD
    RT46: RPM WOT while underway seemed to be about 2500. Boat climbed to about 20 knots, probably would have gone slightly faster, maybe 21, but we backed it down. It was the 16 knots at 2000 RPM's that I wondered about. Did not do WOT with no load. Is that something that should be tested? Never wanted to do that with gas engines.

    Don't know what EGT is?!

    Boat smoked at start up. a little blue smoke at start up, more from starboard engine. I also noticed more black smoke from the starboard when I throttled it up from an standstill. While running though it there wasn't any detectable smoke.

    Chesapeake 46: I have no idea how clean the bottom of the boat was or the gear for that matter. It's possible it's fowled. Where are you located anyway, I'm in North East, MD.

    42Hatteras: Could you define "run conservatively"? From what I've read it seems that cruise on these things is around 2000 RPM's. Is that "conservative"?

    Thanks all for your suggestions and answers!
  6. Capt J

    Capt J Senior Member

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    Jul 11, 2005
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    14,432
    Location:
    Fort Lauderdale
    671 TI's cruise is 2150 rpms and WOT's is 2600 rpms.
  7. RT46

    RT46 Senior Member

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    Old44272,

    EGT=exhaust gas temp

    The Post 42-43 is a great boat and there are a lot of very nice Posts on the market, and now is the time to buy, it really is a buyers maket.

    As FAR AS PERFORMANCE:
    You will want the bottom, fuel, and filters (including air filters) clean to make sure those are not impacting performance. Those things are usually the simple and correctable things casuing poor performance.

    RE SMOKE:
    Some smoke on a cold start is OK and even brand new/rebuild DD's will smoke on start up.
    -The smoke should clear after a few seconds and should be whiteish colored. White is the unburnt fuel not kicking off in the cold combustion chamber. There should be little to no hunting.
    A warm engine should not smoke more than a puff and not hunt on start up.
    -If you get some black somke when you give it throttle, that is the lack of air waiting for the turbo to give more air to the combustion.
    -Under load you should be able to slowly advance the throttle and not get excessive black smoke. If you floor it you will get black smoke.
    -You dont want to see black smoke once at cruise speed and the turbos have cought up to the fuel.
    -Excessive black smoke needs to be investigated.

    RE SURVEY:
    One thing I do recommend is a mechanical survey. Hire a well know Detroit Deisel guy, it will be money well spent.
    -I recommend having the engine surveyor look over the engines before the sea trial and "regular" survey. That way, if you still want the boat you can renegoiate the price before proceeding or back out before you pay for the haul out and complete survey.
    -A good detroit guy can look in the air boxes and visually inspect the condition of the engines without running them.

    RE REBUILD COST:
    -As far as rebuilding, I have a friend who just had a 671TIB in an Ocean rebuild by a well known DD Mechanic for 6K, that sounds really low, but that was only for 6 kits.
    -You can spend a lot more, and most people will quote you around 30K for the pair for a rebuild.
    ***Now, dont forget about the "might as wells".....those are the things you might as well do while you have everything apart....., heads, injectors, cooling, turbos, hoses, alt's, starters, fuel pumps, heaters, air seps, filters, check out the gears, paint...... and lots of other stuff that adds up to lots of money on the final cost. Even replacing all the hose clamps can add up.
    BTW, The heads alone can cost 2-4 K each depending on the valves and availability of exchange vs having yours redone.
    -However, the cost of a pair of new Yanmars could easilly run $125K installed.
    Another option would be those rebuilt Cummins that seem to be the engine of choice for repowers, I think you would be in the $80K+ range for a pair installed.
    -Rebuilding the DD's seems to make sense when you do the numbers for the recreational user.

    The DD 671 is a great engine that can last if not abused.
    A well maintained and cared for 671TI or TIB can last 3-4000 + hrs.
    It is user/owner maint friendly and doesnt require computer or advanced degree from MIT to change the oil and do maint.

    If I were running a charter boat that ran a few thousand hard hours a season, i might think about a different power train and boat.

    If I were looking for a 42-46 SF as a family boat to cruise and ocassionally fish, that is sea worthy, can run with the big boys, and can pull into any high end marina or yacht club to double as a floating martini platform.....
    then I would seriously consider a Post in the 42-46 Range w a pair of good running 671TI/TIB's...


    Good luck,
    RT46
  8. SeaEric

    SeaEric YF Historian

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    out on the dock
    The early-mid 80's 42/43 Post is a nice boat. I owned a 1981 42 with 671ti 450's. My boat had a bimini (no hardtop) and she was a bit faster as a result. Mine did 16 knots at 1600 and 18 knots at 1800. She ran 23 at 2100.

    Engine hours mean less than how they were run. I see that the OP is in Md. so Tom Hug is the local GM Diesel surveyor that you want to look at whatever you buy.

    There are some very nice boats out there now at bargain prices. Happy shopping!
  9. Beau

    Beau Senior Member

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    Location:
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    Does anybody know when Post changed the hull design. I heard the early 43's can be a very wet ride.
  10. mwwhit1

    mwwhit1 Senior Member

    Joined:
    Jan 19, 2006
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    Location:
    Jersey City NJ\Boca Raton FL
    My 84 43' is one of the first with the newer hull design and double spray rails. I don't find it to be wet. Strong quartering wind will sometimes curl the spray over, but I think any boat will do that.

    As for performance, something definitely seems off with the test ride. I have the 450HP TI's, not the 485 TIB's. Boat empty like your test I get 21 knots at 2000, 28 knots at 2500.

    If this boat only gives you 16-17 knots at cruise it wallows along and can be wet at these speeds. This hull comes alive over 20 knots. It is a whole other boat when cruising at 21+ knots as opposed to 16. Much more stable, very little steering needed, and just feels right.

    Any other 43 questions, feel free to contact me.
  11. Beau

    Beau Senior Member

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    Exactly. Before that hull change I've heard that a lot of green water came over the bow. But I have no direct experience.
  12. old44272

    old44272 New Member

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    Location:
    North East, MD
    Last Friday I learned from a diesel mechanic that was tuning the '86 Post 43 that the engines are 450 HP 671 TI's, not 485 HP 671 TIB's. He said that the rack on one of the engines was not adjusted. I'm going for another ride this Saturday before they winterize it. I do know that the starboard engine was hunting and stalling before it was warmed up when I drove it last week. This diesel guy said that he also ran the boat up the bay for the marina a few weeks ago and he observed the same thing. he says it runs like it should now, we'll find out.

    Can someone give me a ballpark figure what these burn GPH (with a clean bottom and running gear)? I've read everything from 25 to 40 GPH. My current boat burns gas at about 18 GPH, so obviously this is another factor I need to weigh!

    Thanks again!!!
  13. mwwhit1

    mwwhit1 Senior Member

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    Location:
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    I don't have Floscans so I can't give you rock solid GPH. The few times over the years I tested, it turned out to be 30-33GPH running 2000-2050 RPM. Not really sure why it is quite a bit more than Chesapeake46 burns. Engines are a bit more HP 450 vs 410. Posts I have read on [Link to membership site deleted] seem to compare to my GPH numbers. Comes right in the middle of your range so good enough for you to budget $$ with. Good luck!!