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Hat 50' Station wagon effect

Discussion in 'Hatteras Yacht' started by BoulderGT3, Jul 21, 2014.

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  1. BoulderGT3

    BoulderGT3 Senior Member

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    I've found a couple of 2005-06 models I'm interested in . There seem to be two big warnings. The first is around avoiding the 3412 as they're too heavy and there were some stringer issues.

    The second is that some mention the station wagon effect while others say it is not an issue. In my experience all have it to some degree in some conditions. I've been on a 62' Viking that seemed pretty bad so who knows. At any rate, I'll trial the boat but what should I expect on the 50' Hat in the cockpit and bridge with front curtains open?

    Thanks,
  2. Capt J

    Capt J Senior Member

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    Bridge you get no ill effects. Expect 30 knot cruise with a hardtop and c 18's......cockpit while running at cruise everything is wet to the touch...... The boat rides best if you dump that 200 gallon bow fuel tank asap......and really rides best 1/2 tank fuel or less.....but still rides fairly good......The 3412's are good and haven't heard any stringer issues, but really you're just burning a ton more fuel to go a few knots faster.

    The 54' rides a heck of a lot better and IMO is probably the best riding SF (production) in the mid 50' range.
  3. BoulderGT3

    BoulderGT3 Senior Member

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    An ex Hatteras rep told me some of the early 50's w/3412 needed stringer rework at the factory.

    All cockpits seem a little wet. Do you think this one is better or worse than say a Viking 52'?

    Thanks
  4. Capt J

    Capt J Senior Member

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    I have no experience on the Viking 52'. But can give you the general characteristical differences between both builders. Both do a good job in Build quality and engineering, that's mostly a tie. On the troll the Vikings will be more stable and also in a beam/stern sea so the Nod will go to Viking there, but the Hatteras is only 2 steps behind the Viking here. Viking also has done a much better job with fishing cockpit amenities than Hatteras in those years (fishbox size/location, livebait well, tackle center etc.). The Hatteras will run better in a head sea. Hatteras' are painted, Vikings are gelcoated so more of a need to wax the exterior.........Not all cockpits are wet.
  5. 993RSR

    993RSR Senior Member

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    Often when people complain about exhaust "station wagon effect" the problem is :
    load/fuel/injectors/props/fuel filters... clean burning motors can roll exhaust back all they want
  6. Capt J

    Capt J Senior Member

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    It's not the exhaust rolling back that's the problem. It's the mist of saltwater or even saltwater droplets on the entire cockpit. After running at cruise everything in the cockpit is soaking wet, including anyone standing back there. The problem is in the design of the house foward of the cockpit not letting airflow backwards and creating a "station wagon" effect. Irregardless of how the machinery is running, dirty exhaust just exaggerates the problem.
  7. 993RSR

    993RSR Senior Member

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    Hmm that does sound like a big pain in the butt. My 45 F/B will get a salt mist covering the saloon doors and cockpit after hours of running in the ocean. Running in the bay I don't notice it. Maybe salt content makes it more noticeable.
  8. K1W1

    K1W1 Senior Member

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    If proper wind tunnel testing was done on these yachts before build many of these problems can be mitigated with minimal effort.
  9. Capt J

    Capt J Senior Member

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    Not just a mist, but everything is as if it justs rained. The bridge ladder the cockpit covering boards, top of the tackle center.....etc....

    I agree with Kiwi, but many builders still do it old school. None of the Cabo's exhibit the station wagon effect because cabo would build a scale model and fully tank test the model in a variety of conditions and would tweak it. They've even had Michael Peters slightly tweak his hull design if need be. Some Vikings are dry as a bone as well. It has to do with how the wind rolls off of the side of the house, and as Kiwi said, sometimes a little tweak will stop it from happening......Sometimes an owner adding a 1/4 cockpit or 1/2 cockpit sunshade will make it happen on boats that don't have it to begin with......it's all about aerodynamics.
  10. PacBlue

    PacBlue Senior Member

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    The station wagon affect is an issue for all fast SF. I am sure the folks at Hatteras have investigated this issue to death, but it does exist much to no one's pleasure.

    I can not think of one production boat mfg that does a wind tunnel test with all surfaces/hardtops/enclosures to redesign their structure, it is just not done in the US or Internationally, and the select ones I have seen were for resistance only. Cruise ships and smoke stack stuff is a different story.

    I would venture to say that there would be significant effort in retooling enough to the extent of eliminating this issue on this particular model. And with all the owner add-ons, towers/hard tops/riggers/etc. it would be a major cost/challenge to account for these floating variables.

    Back in the day (70s/80s), We owned a Laguna 10 metre (built by American Marine aka Grand Banks) and they had an aluminum scoop at the edge of each deckhouse side to help eliminate the vacuum (negative pressure) in the cockpit, and it was an abysmal failure. We would regularly observe diesel smoke residue inside (!) the refrigerator down below, no telling how much exhaust we breathed over time :(

    My 2 cents - this can easily occur when engine air intakes are located under the cockpit gunwales but this Hatteras model appears to have classic side hull air intakes.
    Last edited: Jul 24, 2014
  11. Capt J

    Capt J Senior Member

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    Cabo does
  12. PacBlue

    PacBlue Senior Member

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    Does what?

    Are you saying they rent Wind Tunnel time and model test hull/superstructure accessories all together? Which Flybridge boat did they do this on, the short lived 52, because I doubt if they did it on the 47/48 which was more an in-house fly by the seat of your pants design. A Tow Test in a water tank is not the same deal.

    I have seen Hatteras do tests on production boats with tell-tale streamers attached to all surfaces and video taped, but would be curious to know if they have moved on to wind tunnel testing in the recent past.
  13. bluesuit

    bluesuit Member

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    How about a 54 Bertram and it's station wagon effect? I had an '81 50' Hatteras sf and the cockpit was dry. Didn't notice much station wagon effect on her. However, when the intercoolers got dirty I'd get some soot on the transom.
  14. Capt J

    Capt J Senior Member

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    The 54' Bertrams don't exhibit it if I can remember correctly. I've only run 2 and very briefly. Don't quote me on that.

    Cabo did it on the HTX models...40', 44' etc. I can't think of any Cabo that has the station wagon effect in any of the boats they've made.....
  15. Bill106

    Bill106 Senior Member

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    I've also seen a deflector scoop added to the aft edge of the hardtops, much like you see on old station wagons and SUV's to direct airflow down into the low pressure area behind the cabin. Since there usually isn't a lot of air flowing across the hardtop's boundary layer they didn't do much but anything helped!

    Some do pay a lot of attention to minimizing station wagon effect. Donald Blount and I worked a few projects where that was a high priority. A couple methods we used combinations of interceptors on leading and aft edges of superstructure and also forced air ducted from the front of the bridge to the pit, both worked very well! In fact the boat in my signature pic has the ram-air system which draws engine room air from the flybridge front boundary layer air flow and uses the excess to "pressurize" the pit, no mist unless it's really snotty!
  16. CTdave

    CTdave Senior Member

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    Hi
    I have a '96 50 Hatt & have no issues at all with the "station wagon effect".
    I just returned from a 3-1/2 hr run to and from Block Island, bridge fully open on the way there. On the way back, we expected t-storms & closed the front and the first two forward panels on the sides. Absolutely no moisture or fumes at all running 29kts the whole way.
  17. Capt J

    Capt J Senior Member

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    I saw the station wagon effect pretty good on a 2004 50'. It had no strataglass but just a hardtop. The cockpit was dripping wet everywhere, always when running at cruise.
  18. mark 10

    mark 10 New Member

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    So this backspray is common, I thought it was just me ! does anyone with a 06 50' hav an issue with the a/c units reading high pressure when u run? Ive gone nuts trying to fix problem
  19. Capt J

    Capt J Senior Member

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    I haven't noticed a/c's reading high pressure. A/c sea water pump is either picking up bubbles or getting airlocked. Did someone put a non factory clam shell over the intake or something?
  20. mark 10

    mark 10 New Member

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    moderater wanted me to start a new thread, check it out !