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Old 06-19-2022, 06:49 AM   #61
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Think there’s little question stabilization is worth the money and effort. About that there’s a general consensus. The discussion is which type.

Fish are quite limiting for many people. Require significant depth for deployment and significant effort as well. Need to go to storage position (except possibly in some anchorages) when not in use. Not an issue for voyaging boats but a real issue for those utilizing a boat intermittently in a coastal setting. Canadian warning that they may decrease ultimate stability if one fails maybe overwrought but not without supporting data.
Fins increase wetted surface, turbulence in use so parasitic drag. Hence increase fuel burn. Should be tuned in surface area for expected speed through the water. That maybe ideal for FD hulls running with very limited different speeds but not for SD hulls with wide variation in speeds of operation. Damage with groundings or strikes maybe overwrought but does occur.
Gyros need genset running on virtually all boats. In all but extreme weather said to be the most effective mode of stabilization. Takes time to spin up or down. From limited experience found this to be a non issue as weather forecasting is adequate to know well in advance if needed. But downside of ~3/4 g/h of fuel burn exists. Comparing to lost speed or fuel burn of fins is case specific but one would think gyros are more energy hungry. Gyros in vacuums said to be more effective, spin faster, less energy intensive per rpm than non vacuum but at expense of breaking and reestablishing vacuum if internal service required.
Magnus said to be as effective as gyros. Retract so less issues in skinny or debris laden waters. Less energy intensive. However do create drag (same as fins) more pronounced at higher speeds. Minimal drag if not deployed.

Not an expert but think above is a decent summary. Nothing is perfect or suitable in all settings. In choosing for a new build as per O.P. would think decision should be driven upon what he intends to do and where.
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Old 06-19-2022, 07:48 AM   #62
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An interesting advertising article comparing "vector fins" (a new term for me - apparently curved fins) vs gyros.

https://www.yachtingmagazine.com/boa...fins-vs-gyros/

Many of the fin-benefits are unique to "vector" vs straight fins such as traditional Naiads.

Also from Imtra, a discussion on their vector fins compared to straight fins. Apparently, they create lift which is their magic.

https://www.imtra.com/learning-cente...hich-is-better

Obviously a slightly biased piece, but much has the ring of truth.

Peter
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Old 06-19-2022, 07:49 AM   #63
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After reading all the opinions being posted, I will be focusing most of my research time on the Mantus system, it just seems to tick the boxes for me, especially in Australia with the large NM we log in the Pacific trips and East Coast of Australia, planning large voyage to PNG and Indonesia and I can’t see much sea-keeper service available in the area so best to keep it simple and Mantus kinda of does that for me tbh.
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Old 06-19-2022, 08:06 AM   #64
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After reading all the opinions being posted, I will be focusing most of my research time on the Mantus system, it just seems to tick the boxes for me, especially in Australia with the large NM we log in the Pacific trips and East Coast of Australia, planning large voyage to PNG and Indonesia and I canít see much sea-keeper service available in the area so best to keep it simple and Mantus kinda of does that for me tbh.
Not familiar with Mantus. Do you have a link? A quick Google search didn't turn up anything applicable.

Peter
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Old 06-19-2022, 08:41 AM   #65
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... I will be focusing most of my research time on the Mantus system... planning large voyage to PNG and Indonesia and I canít see much sea-keeper service available in the area so best to keep it simple
Seems like an excellent conclusion. I was really surprised to read about the amount of maintenance required by gyros. And if that (factory tech) maintenance is required every 500-1000 hours like stated, then that would be a non-starter. Personally I'm a big fan of flume tanks, based on the few I've known, but they're a bit too non-conformist for most.
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Old 06-20-2022, 05:36 AM   #66
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Owning a SeaKeeper and having had a detailed educational with a certified tech can say service is replacing one easily accessible zinc once a year. I will do this myself. Big service done by certified tech is at the thousand hour marks. Factory service timing is variable. From talking with tech usually around once a decade.
My read is less not more service than with fins.
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Old 06-20-2022, 05:44 AM   #67
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Owning a SeaKeeper and having had a detailed educational with a certified tech can say service is replacing one easily accessible zinc once a year. I will do this myself. Big service done by certified tech is at the thousand hour marks. Factory service timing is variable. From talking with tech usually around once a decade.
My read is less not more service than with fins.


I hear what you say, in part at least. But 1000 hr service is going to be far more often than once a decade for anyone who unties their boat from the dock on a regular basis. Do you have a good estimate of what the cost of that 1000 hour service will cost?

With my Naiads its seal every 3 years and a bit more for every second one to fully pump through grease etc. Even then a 1-2 boat buck cost is all it is.

I wont ask what an internal bearing replacement what cost given removal of the heavy item from the boat and return to factory, but do you know at what hours that would typically occur?

I know you like the SK, fine. But until you give some numbers I cant accept your closing sentence (in red in quote) at face value.
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Old 06-20-2022, 06:41 AM   #68
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Not so bad
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Old 06-20-2022, 06:49 AM   #69
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I hear what you say, in part at least. But 1000 hr service is going to be far more often than once a decade for anyone who unties their boat from the dock on a regular basis. Do you have a good estimate of what the cost of that 1000 hour service will cost?

With my Naiads its seal every 3 years and a bit more for every second one to fully pump through grease etc. Even then a 1-2 boat buck cost is all it is.

I wont ask what an internal bearing replacement what cost given removal of the heavy item from the boat and return to factory, but do you know at what hours that would typically occur?

I know you like the SK, fine. But until you give some numbers I cant accept your closing sentence (in red in quote) at face value.

Yeah alls good Hippo that’s what Onan said about my 2 x 12kva generators I would only need one lol �� …. I am so happy to of installed two, one for redundancy as the amount of time spent on controller issues on them has been insane and with out having 2 of them we would of been very inconvenienced and have to of cut short many a long journey especially in the Pacific Ocean , I am honestly getting to the stage of anything I can’t service myself via email or phone call I don’t want on board, it just becomes more of a hassle than the benefit imho.
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Old 06-20-2022, 06:50 AM   #70
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In SF Bay, I hauled for paint every 2-3 years and replaced seals every second haul at a cost of around $1500. I also replaced an oil cooler a few years ago that was a few hundred bucks plus the cost of oil. 25-yrs of ownership, probably around $7k in service in todays dollars. Maybe a bit more but not much. Penalty for deferred maintenance is a weep or leak but you can keep going for quite a while. I also had to replace a bushing that was knocking. There is a removal tool that aids removal of the fin but it's pretty straightforward and fairly easy to fabricate.

Best I can tell is fins require more frequent service compared to Seakeepers but lower tech so it can be done by any decent mechanic. The penalty for deferring maintenance is manageable with fins, more risky with gyro. A bearing failure on a high RPM massive weight will render the system inoperable (or risk catastrophic failure).

I think it fair to say the longterm maintenance of Seakeeper and Fins is roughly equivalent. The routines and intervals are different but over a 10 yr period it is likely close enough that it wouldn't skew a decision for one or the other.

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Old 06-20-2022, 06:54 AM   #71
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I am honestly getting to the stage of anything I canít service myself via email or phone call I donít want on board, it just becomes more of a hassle than the benefit imho.

I'm kinda at that point too. If I can't get enough documentation on how to service the thing (and access to any computer tools needed for diagnostics), I'll go buy a different one that doesn't require as much access to factory techs.
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Old 06-20-2022, 07:03 AM   #72
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I'm kinda at that point too. If I can't get enough documentation on how to service the thing (and access to any computer tools needed for diagnostics), I'll go buy a different one that doesn't require as much access to factory techs.
Getting much harder to do. Many modern Tier 3 engines are difficult for a DIY owner to service. Other equipment aboard are similar such as watermaker and many nav systems. Refrigeration and HVAC are mostly discard and replace instead of repair Over the last 10 years there has been a a trend towards electronic interfaces to control all creature comforts. God help you if there is an IP Address conflict down the road.

It's a balance. I've skewed hard towards the DIY mindset because I'm not a great mechanic and I plan to cruise in out of the way places. You give up a lot of cool stuff by doing that.

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Old 06-20-2022, 07:22 AM   #73
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Getting much harder to do. Many modern Tier 3 engines are difficult for a DIY owner to service. Other equipment aboard are similar such as watermaker and many nav systems. Refrigeration and HVAC are mostly discard and replace instead of repair Over the last 10 years there has been a a trend towards electronic interfaces to control all creature comforts. God help you if there is an IP Address conflict down the road.

It's a balance. I've skewed hard towards the DIY mindset because I'm not a great mechanic and I plan to cruise in out of the way places. You give up a lot of cool stuff by doing that.

Peter

I agree that it's not always possible. But I'm used to dealing with electronics for service in cars, etc. So I'm not afraid of maintaining an electronic engine, I just want to be able to get my hands on the tools and documentation so I can do more of the stuff before having to call for help. Instead of "uh oh, it's got an error code, better call the dealer to come out and scan it"
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Old 06-20-2022, 07:42 AM   #74
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Tier 3 engines are fine to service and repair there not that complicated, it’s the company’s manufacturing them is the problem , if you are going to build marine engines or any marine components you need for all proprietary service and maintenance information to go on board with the product, I’m so sick of having to beg for information in regard to repair it just seems so wrong, these products are so expensive and relatively easy to maintain and repair if the knowledge is shared like it was in past times ie pre 1990.
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Old 06-22-2022, 07:59 AM   #75
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Went on the internet looking for a SeaKeeper service manual. No joy. Told by wrench this is intentional by the company. They want no one but certified technicians opening the thing. But also told I could replace the zinc myself now that I know where it is. So far we’ve done ~1800nm and have yet to go back/forth Newport to Bahamas. We’re not dock queens. Still expect a $5k plus bill every 1000h. Currently under 500h. So you have more DIY with fins than gyros and tech hourly costs keep climbing but all in all think (don’t know) service costs will be a wash. Every 200h will replace zinc. As a new owner don’t know if that’s the right interval. Little information I could get suggests it is. I’ll pull it every 100h or 3m until I know. It’s five bucks, some plumbers tape and 1/2h of my time. Zinc we just pulled needed replacement.
Look at their website. SeaKeeper seems to be the dominant gyro vendor. They have service centers just about everywhere as they are popular. Don’t think that’s a limitation. I’m on a single screw common rail trawler run coastal. I’m no longer crossing oceans. Some people think they’re Shackleton. I think I’m a slub out having fun. Got other stuff to worry about.
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Old 06-22-2022, 10:49 AM   #76
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But also told I could replace the zinc myself now that I know where it is. I’ll pull it every 100h or 3m until I know. It’s five bucks, some plumbers tape and 1/2h of my time. Zinc we just pulled needed replacement.
For the record, hydraulic fins always have some sort of sea-water cooler....and a zinc somewhere.

I agree Hippocampus. After the dust settles on the two systems (fins/gyros), it's essentially a wash on maintenance. I totally understand there may not be a Seakeeper service center everywhere, but in thinking about it, not like the thing self-descructs at 1001 hours. It's something you can plan a year (or more) in advance - just as people do about haul/paint.

Glad you're putting so many miles on your new boat. Impressive. As someone who's watched you throughout your purchase journey, great to see it come together. Thanks for being so generous with sharing your experiences!

Peter
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Old 06-22-2022, 11:18 AM   #77
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Magnus vs Fins

I've been reading more about Magnus effect and zero speed stabilizers, particularly on the Rotorswing Holland website. Some comments / questions:
  • First, I love the idea of going with electric stabilization versus hydraulic. Hydraulics are just one more system to bother with, unless your vessel is already equipped. But for a new construction, I don't want to mix too many systems. Electric systems, their dependability and safety, have increased since the days of the Pardeys who wouldn't allow even an electric flashlight onboard (exagg.).
  • The vendor does not post power requirements, but I wonder what the difference would be between a Magnus and a fin. I assume that the Magnus would require less power, and this would be important for the "zero speed" function, since running it all evening off a battery bank would be important.
  • What is the voltage requirement for electric systems, DC or AC?
  • Although I personally lean more towards the Magnus, I don't like the fact that they stick out 2-3 feet outside the envelope of the hull, and outside the beam. Fins generally fit within the beam/draft boundary. At least this is what their website shows.
  • Does anyone have indicative pricing to compare Magnus vs fins?
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