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Mangusta 72 - Arnesons

Discussion in 'General Yachting Discussion' started by Danvilletim, Nov 29, 2017.

  1. Danvilletim

    Danvilletim Member

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    We ve been looking at a couple Mangusta 72s. Reported cruise is 34kts. WOT 40kts and economic cruise is 31kts at 90gph. That's an amazing cruise speed and economy.

    So how does this boat handle goi g down the inter Coastal? If you are moving the boat 800 miles north what would you cruise at?

    What else to watch out for?
  2. rcrapps

    rcrapps Senior Member

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    72', 30kts, Arnesons, in the ditch, all those idiots, snail botes, lil fishing boats, all those no wake zones?????
    Shallow water, your bow may never come down.
    Good AP to keep her stright?
    It's not what the boat can do, it's what the ditch makes her do.

    Skip the ditch and save what sanity you have left, stay out side.
  3. Pascal

    Pascal Senior Member

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    At least half the ditch is pretty wide, undeveloped and deep enough to run fast although at the peak times traffic means you ll have to slow down quite a bit.

    I m hoping the AP comment was meant as a joke :)
  4. rcrapps

    rcrapps Senior Member

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    The only time I ran a fat boat with surface drives, it could not keep a straight line.
    I assumed that was typical since.
    I used the Auto Pilot to help me drive nicer lines.
  5. Danvilletim

    Danvilletim Member

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    Trust me when I'm on board I'd prefer to go 30 and outside and willing to wait for that window...just want to understand the downsides of surface drives. The boat has bow and sterns so not worried about docking.
  6. 30West

    30West Member

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    I think you were asking about least cost delivery speed on another forum, at least that is what I was figuring out. That would have to include captain and mate costs, slip and lodging costs every night it takes, other things I'm not thinking of. It sounded there and here like you would not be aboard enjoying the awesome speed, just wanted least cost delivery speed.

    This is likely a better forum to ask that question in.
  7. Danvilletim

    Danvilletim Member

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    Nope that's not the question. I have plenty exp w delivery captains, crew on both coasts.

    The question is the performance characteristics of Aronson drives at hull speed.
  8. rcrapps

    rcrapps Senior Member

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    Let me update my comment. The boat could not drive a stright line at low speed. Idle or slow zones. At speed, she was a blast and stright.
  9. 30West

    30West Member

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    I haven't driven with surface-piercing drives, but out of engineering curiosity I've done some reading about them.

    Fully submerged, the large diameter props put a lot of strain on the engines and drive trains. Not a problem at hull speeds, a bit inefficient, but not putting out a lot of power anyway.

    From hull-speed to cruise-speed, water is covering or mostly covering the props, they are sometimes cavitating sometimes not, sometimes in foam and sometimes in clean water. The drives and engines and drive trains are not happy, not efficient, and working very hard whenever the props are submerged, lots of rpm surging. The ride is similarly not a happy one, lots of vibration and surging, alternating asymmetric thrust can make it a wild ride requiring a lot of steering inputs to maintain course as the props are in different flow environments.

    During a hole-shot start, the props quickly cavitate, rev up to speed, and start grabbing water at the blade tips for acceleration. It isn't smooth, but it is predictable, symmetric, and short duration.

    They suck between hull speed and cruise plane. Slowing down a bit when going gets rough is not a good option.
  10. olderboater

    olderboater Senior Member

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    I'm not a fan of surface drives. However, properly installed on a good boat, they're not as bad as you're describing. I have driven with them on a Pershing. Their design purpose is speed and they provide it very well. Typically they don't plane until you reach a speed of 20-25 knots, then you might back off just a little and stay on plane. It's that awkward area between 8-10 knots and 20-25 knots where they don't handle or perform as well. During that period the drives are submerged and less efficient. Holding a line is more challenging. Now, as to cavitation, that's going to depend on the boat and the installation. I did not experience an issue with it on the Pershing, but my time on it was very limited. We do desire a faster boat one day and most do have surface drives. However, that's not personally our choice. We'll probably go the route most wouldn't and go for jet drives.
  11. CaptPKilbride

    CaptPKilbride Senior Member

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    It will vary from boat to boat, but generally they are manageable at hull speed. It's not a fun time, but it can be done. If it is a wide open area, and you can get the boat to plane, you will probably see an increase in speed at the same power setting due to shallow water effect. For the 800 mile trip, on days when you cannot run outside you will have to choose to stay put for the day and enjoy where you are, or trudge through getting another 80 to 100 miles knocked down at hull speed.
    I am in olderboater's camp, jet drives would be my preference as well.
  12. captaintilt

    captaintilt Member

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    I'll second CaptPKilbride and Olderboater and shoot for Waterjets on something that you will want to be able to go slow and still have "bare steerageway" without constantly working the helm. I know of some larger Mangusta's with RR Jets on them for sale currently that would be a good look as well, and still have the ability to be a very comfortable boat for running for those unpredicted times of having to jump on the inside. However, I also second everyone's advice, and making a trip North or South from Florida to New England, just take those "weather days" and stay at the docks and enjoy the sights and sounds of the local community. I got held up in Beaufort, NC at the Town Docks for a Tropical Storm last year for 3 days, and while I've been to Beaufort numerous times before, I was able to go over to the Islands, found a great church service on Sunday morning, went paddle boarding in the creeks, and had dinner with some locals and didn't want to leave when the weather finally broke. Would be happy to help you find something that works for you and also look at Waterjet boats, and CaptPKilbride and I have talked Jet Boats in the past :D
  13. olderboater

    olderboater Senior Member

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    Omg, this is going to drive some people bonkers that there are now three of us who like Jet drives.
  14. captaintilt

    captaintilt Member

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    Ha! Jet Drives have came a long way and a perfect for some applications, and not so perfect in others. I tend to be the optimist and if it looks like it can work and the numbers work out for the owner and Engineers, then they work great and don't cost a years salary to maintain and take care of when they are installed.
  15. Liam

    Liam Senior Member

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    Downsize is that they need servicing more then shafts and you need to be careful on the anodes.
    Advantages is that if you hit something with the propellers it is very difficult you sink. Maneuvering is not as bad as they say.

    If you touched 40 knots then the 72s you are seeing has the 1550hp which is what I would suggest on the 72. 1300hp Man are just okay and would give 35 knots WoT.
    Lovely boat and if in good condition is still one of the best 21 meter hard top boats ever designed. Again a design to Stefano Righini, who tend to have some of the Viareggio area builders under his belt.

    The problem with most jet drive yachts in this size is that most of the designers tend to go a flat Vee hull aft, which tend to make them less sea worthy at the speeds they need to go. The exception being to this was the AB Yachts, but for example the Arno Leopard as the 24 is flat low Vee aft.
  16. olderboater

    olderboater Senior Member

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    And AB Yachts is who we'd be interested in. We chartered a 116 and while it wasn't one of their fastest, it was a very nice boat. We had very limited time and ran it fast. We were very impressed and loved the handling and performance.
  17. Danvilletim

    Danvilletim Member

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    Great info. I can't wait u til the kids are thru college and we can go around the world at 10kts. Until then, fast is better.

    Are jet drives more maintenance than arensons?

    Also any input on a 80' jaguar?
  18. rcrapps

    rcrapps Senior Member

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    Woow, Maintenance???? Near zero (jets) vs mega bux yearly (surface drives).
    Think stern drive gimbal boots and then let your nightmares begin.
  19. CaptPKilbride

    CaptPKilbride Senior Member

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    Stern drive gimbal boots?
  20. rcrapps

    rcrapps Senior Member

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    Yep, you will have boots also.
    ad.jpg
    In warm water, nearly every year service. Careful dive service every month.

    Oh, boots, bellows. Big black rubber (expensive) things.

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