Seakeeper? Other things?

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NSM

NSM

Veteran Member
Joined
May 15, 2022
Messages
91
Location
Tacoma
Vessel Name
Hold Fast
Vessel Make
Helmsman 43E
We are going for it and buying a new 43E. The last option we are chewing on is a Seakeeper gyro. Any thoughts?

Our cruising will mostly be in the PNW but will also likely head south down the coast and possibly out to the Caribbean.

Any other options that aren’t on the regular list?

Cheers
Scott
 
Lots of experience here. We looked at both and I ultimately went with keypower fins on our North Pacific 45. Can’t go wrong with stabilizers!
 
NSM said:
We are going for it and buying a new 43E. The last option we are chewing on is a Seakeeper gyro. Any thoughts?

Our cruising will mostly be in the PNW but will also likely head south down the coast and possibly out to the Caribbean.

Any other options that aren’t on the regular list?

Cheers
Scott
Click to expand...

Congratulations on the decision to move ahead.
 
Have a SeaKeeper 5 on a NT 42. Went from sail to power because wife’s balance is a wee bit off after fracturing her ankle falling off prior boat on the hard. All I can say is it’s amazing. Still go up and down but not side to side. Thing is mounted in lazerette so there is some loss of storage. It’s midline but does affect bow to stern trim. On our first trip we entered Deltaville tired and in the dark (2am). First time there and was told where to slip the boat but couldn’t find it. Circling around just outside the marina ran aground. Having a single, full keel and nothing sticking out meant that event was trivial. Took a few seconds to be free and no harm done. Big advantage to that set up.
Downsides are time to spin up and electrical draw. If on shore power just let it spin up as we do our pre exit chores. On anchor while during morning coffee and absolutions. Given you need the genset add 3/4 to 1 g/h so some impact on range.
Overall think service and expense will be less than for fins. Still if I was not to ever be in skinny water and the program was only blue water I’d do fins. Gyros will give you decreased roll to a point. Once that point is exceeded and all precession has occurred you get nothing. Whereas fins will give you something as long as the boat is moving forward. So far decide before moving if we’ll run the SeaKeeper or decide to turn it on early when conditions change while running. The delay hasn’t been meaningful. If I had fins given immediate effect would do things differently but don’t think it matters much as you look at weather at least daily.
The presence of the SeaKeeper was one of the reasons I bought this boat. Prior owner got some money back for it being in the boat but surely didn’t get his installation cost which is significant. Also allowed me to see if the installation was beefy enough. Absence of any stress cracking or support changes let me know they did an excellent job. The SeaKeeper promo used my boat to demonstrate the effect on the unit. Its available on YouTube
 
The only negative is, the sea keeper need 120vt.
 
Alaskan Sea-Duction said:
Need room too...
Click to expand...

The installation I saw on a 41 ft AT was more room than I was prepared to give up.
For intermittent use, electric is the way to go. For heavy use, hyd or over size electric. For electric remember, you need healthy batteries. Then don't forget the alternator and charger.
 
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Let me tweak the way I asked the question a little. Do any of you not have stabilization and wished you did? Or is the boat a sufficiently stable platform as is even in open water.
 
I do not have stabilization on my Willard 36 which is a full displacement boat. I’ve had it out in confused 10 footers and while I felt safe it would have been very nice to have some form of stabilization. My 42 foot semi custom boat has paravane stabilizers and without the stabilizers in is slightly more rolley than the Willard in comparable waves without the stabilizers in. It becomes extremely comfortable the moment the fish go in the water. A well designed boat shouldn’t need them to feel safe but is damn nice to have just for comfort factor. I don’t think I would consider any new build not having some form of stabilization unless it was a plaining hull and I had the money to run it at speed all the time.
 
NSM said:
Let me tweak the way I asked the question a little. Do any of you not have stabilization and wished you did? Or is the boat a sufficiently stable platform as is even in open water.
Click to expand...
That is a bit like asking a tadpole what it's like to be a frog. The moment an owner of a non-stabilized boat were to spend any time on a stabilized version, I can almost guarantee they'd say something along the lines of "don't let my wife see this...."

An easier to answer question might be "for those who own a stabilized boat, how many would consider stabilization optional on their next boat?" If the answer isn't zero, only because someone didn't understand the question.

BTW - I believe it was David Gerr (naval architect) who states stabilization does nothing to change a boats ultimate stability. It is a comfort item. While I understand his technical point, I do believe there are ample safety benefits of having a stabilized platform.

This is settled science. Stabilization is a game changer for these style boats. Only questions are affordability and what type of stabilization makes the most sense of your boat.

Peter
 
Hippocampus said:
Circling around just outside the marina ran aground. Having a single, full keel and nothing sticking out meant that event was trivial. Took a few seconds to be free and no harm done. Big advantage to that set up.
Click to expand...

If the Seakeeper marketing material is correct, the world's waterways should be littered with holed Hatteras and Nordhavn yachts, both of which have thousands of boats with fins - millions of miles under their collective keels. The claim of "vulnerable appendage" is fear mongering - it's a freak accident of incalculably low occurance. Is there a chance? Sure - sort of Jim Carrey in "Dumb & Dumber." Might as well purchase meteorite insurance. I can tell you I have grounded my stabilized boat many times (including intentionally) - it's why I love a full keel displacement hull.

There are pluses and minuses to any stabilization system. The unique benefits to gyro is stabilization at anchor, and meteorite insurance of no exposed appendage. The main minus is you have to run your generator for them to work. Many boats run their generator full-time anyway for living comfort so may be a non-issue. If not, TCO of running a 12kw generator is probably north of $10/hr so non-trivial

That said, depending on cruising grounds, at-anchor stability can be incredibly desireble. My boat has a very useful set of flopper stoppers that take about 10-mins to deploy or stow. Cost of a well designed and nicely finished flopper stoppers setup (outriggers) on a 45-foot boat is in the $2k-$5k range so not trivial either.

Stabilization is a game changer. What type is best for a particular owner or boat is variable based on circumstances.

Peter
 
Once the gyro fully spins up what's the on-going power need, isn't it like 1kW-hr? If you're planning on cruising a lot, then I'd ensure that the gyro can run off an inverter powered from the main engine, even if that means a dedicated alternator and inverter. When I was cruising a week at sea I would hate to have to run the genset 24/7.

Regarding to OP's original question about whether stabilization is needed or not, for a cruising boat (PNW to Caribbean sounds like "cruising" to me), the answer is YES. Of course. My big boat was 65ft, steel, low windage CoG, 50 tons, and damn did I wish I had stabilization of some sort. Especially at anchor off a beach. Especially in 5ft beam seas. Especially in 20ft+ seas. The only time I didn't feel the need was when running downhill, where a champagne glass wouldn't even spill, but that's a narrow range of about +/- 30°.

I'm not going to argue flopper stoppers versus active fins versus rolling chocks versus gyros. However, 100% you will NEED roll reduction of some form for a 43ft fiberglass cork traveling open ocean like you intend to.
 
Lee,

I have the same question as Mako. Will the Seakeeper run off the inverter after spin up? Like Mako's idea of a dedicated alternator and inverter if necessary.

We have a 160 amp alternator and 700 watts of solar. The alternator is not externally regulated but is an easy upgrade. I had the mounts and wiring for a Seakeeper installed during construction.



Thanks,

Rob
 

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Taking that one step further, I’d suggest upsizing your lithium bank an extra 12kW or so to allow operating the gyro overnight when in a rolly anchorage.

BTW when I was researching gyros I was leaning more towards the QuickItaly units.
 
Datenight said:
Lee,

I have the same question as Mako. Will the Seakeeper run off the inverter after spin up? Like Mako's idea of a dedicated alternator and inverter if necessary.

We have a 160 amp alternator and 700 watts of solar. The alternator is not externally regulated but is an easy upgrade. I had the mounts and wiring for a Seakeeper installed during construction.

Thanks,

Rob
Click to expand...
It should as long as you have the inverter capacity.
The DC draw will be considerable depending on the sea state and the
size of the SK unit. I'd expect 100-200 amps though.
Presumably less in a calm anchorage.
 
Don’t know if draw really increases or decreases that much depending upon sea state. Believe it changes some because the hydraulics work more as sea state worsens. But the gyro spins in a vacuum at a fixed rpm once spun up. Don’t think the energy to keep it spinning at that rpm changes much.
Yes I’ve looked at draw while it’s spinning up. Seems highest in the beginning and gradually falls as you approach final rpm. Hard to quote numbers as there are multiple other draws which are intermittent. Even at final rpm load on the genset varies. So unable to give any sort of confident answer to above questions. Can see the sense on larger boats to have two gensets to support different levels of draw. On a small would wonder about a clutch allowing the main engine to drive a electrical supply when needed. At high speeds most SD hulls become less rolly. At lower speeds you roll more but the propulsion engine isn’t fully loaded so has excess capacity for an additional load. Good thoughts above. However you’re still turning hydrocarbons into electricity. Is there really enough of a difference in efficiency between having the propulsion engine or genset engine doing it to justify additional stuff?

Got to think sliding a hull through mud or turning while resting on mud is easier without appendages sticking into the mud. Wasn’t thinking fins would break, be damaged or damage the canoe body. We just pivoted. Gave a bit of throttle and were off. Remember running aground in a friends boat with a winged keel. It was an anchor. Even waiting the tide out a bear to get unstuck.
 
Not a great picture. I've circled the fin and as you can see, it's well above the keel, and well inside the outer beam width of the boat. Would be very difficult to have a fin entangle the bottom, even a really soft bottom. This is a very common installation.

Years ago we were in the Sacramento Delta. We'd gone of on a small tributary that rejoined the main river 12-miles up. Problem was there was a silt bar that was probably 3-feet deep - an issue for Weebles that draws 3'9". Rather than backtrack, we plowed through. Quite the milkshake behind us, but we made it no problem.

That said, my fins originally didn't have kelp cutters to deflect kelp or lines. I picked up a lot of kelp a couple times which was a PITA to clear once wedged. The deflector solves this.

Peter Screenshot_20220612-105203_Photos~2.jpg
 
Thank you all for the input. Makes it easier to swallow the not inconsequential cost.

Cheers
 
This from the SK website for a SK5 for boats 40-45' (approx)

Power Consumption
Spool-Up Power
2300 Watts Max
Spool-Up Power Input
N/A
Operating Power
1050 - 2300 Watts (Sea State Dependent)
Operating Power Input
N/A
AC Power Input
110 or 220 VAC, 50/60 Hz
Control Power
125 Watts
Control Power Input
12 VDC @ 10 Amps
Seawater Pump Power Input
Over Current Protection based on installed pump rating
12 VDC @ 15 Amps Max
 
Thanks good to know. Would add in apparently it’s good to run the cooling pump for awhile even after you stopped using it to protect the bearings as it spins down so beyond the increased draw while spinning up there’s draw spinning down. Of course I only could perceive the draw at a given moment.
 
That does make it more attractive especially in areas where generator is typically not run full time. I like the idea of a second dedicated alternator (250 amp @12v), a decent bank of AGM batteries, and a 3000w inverter. For $5k-$6k, you are preserving the generator while underway and likely offsetting the install cost in 700-1000 operating hours. However, if minimum Seakeeper power is 1000 watts, I doubt it's practical to run the system at anchor for more than a few hours even with a large LiFePO4 bank.

Would be interested to know if this has been done?

Peter
 
The reason that mounting a gyro stabilizer is so critical is due to the large
forces at play when stabilizing is happening. Those forces come from
electric or hydraulic actuators that use a lot of energy while they work.
A 3 or 4 kW inverter ought to be able to keep up with enough batteries,
at least for a few hours.
 
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Surprisingly, according to a demo at a boat show by Seakeeper, the unit does not need to be mounted on or even close to the centerline. In fact smaller boats had them mounted far off to one side where there was normally a storage area. If someone is considering adding one, they will consult with you on your particular boat model.
 
I’ve been investigating the Quick MC2 gyro stabilizers for my NT 37. Smaller, cheaper, no through-hull cooling required, come in both AC and DC models. Sounds too good to be true! Lots of talk but haven’t yet found anybody who has tried them on my or a comparable model boat.
 
backinblue said:
Surprisingly, according to a demo at a boat show by Seakeeper, the unit does not need to be mounted on or even close to the centerline. In fact smaller boats had them mounted far off to one side where there was normally a storage area. If someone is considering adding one, they will consult with you on your particular boat model.
Click to expand...
Location not being as critical as the structural sturdiness of the area, of course.
The closer to the center of motion a gyro can be mounted, the
more efficiently it can do it's job, no doubt.
 
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KnotYet said:
Location not being as critical as the structural sturdiness of the area, of course.
The closer to the center of motion a gyro can be mounted, the
more efficiently it can do it's job, no doubt.
Click to expand...

I agree, especially on the sturdiness, I was just surprised that centerline is not required.
 
Some installations use two units. Seakeeper recommends this in cases where there are space limitations for a single unit, and claim that the effects are cumulative, so a SK4 and SK2 used together are equivalent to a SK6. No need for centerline mounting.

This might offer a way to manage power requirements a bit, as you could keep stabilization running at 2/4/6 according to anticipated need.
 
Totally agree for a FD hull fins are well protected in most grounding situations. But for many SD hulls and even more so for planing hulls think that’s not the case. Think that’s augmented by the occurrence of commonly running aground in settings where depth is rapidly changing.


Like that my engine room has enough space for access. Putting more stuff in to have the SeaKeeper run off the propulsion engine would mean more difficulty getting around the front of the engine. So from above post if I can find the space I can put in another small genset for ~$6k or increase the hours on the existing one meaning it will need replacement sooner. Don’t think the economics are much different and having another thing taking up space and needing service is inconvenient.
Our SeaKeeper is on the stringers that run the length of the boat. Minimal reenforcement was required. It’s midline under the center lazerette access hatch so we have full access to all sides of the enclosure, pumps and related paraphernalia from above and side hatches. Perhaps on larger boats retrofitting off midline is possible. But suspect on many boats in the 40-50’ range placing it on existing support structures with additional beefing up if necessary would make more sense. Usually that means midline or close.
For fuel usage think it does decrease range but so far in use has minimal impact. Genset is 3/4gph. But SeaKeeper is on when we’re doing 7-10k. When going faster it’s rarely necessary. Our main propulsion engine is miserly at 7-10k but fuel use dramatically increases at >10k. So if we run at 7-8K with the SeaKeeper on we are using much less fuel overall than running at higher speeds and are still very comfortable. Coming from sail 7k-8k is just fine with us. Just ran from Deltaville VA to NEB RI on 278g. Went against current lower NYC and alternated with and against throughout L.I. Sound. Minor chop except one day in L.I. Sound and through Block I sound. Then 4’. Happy to trade fuel for comfort as the wife could put things down without them moving and no need to hold anything when you moving around. Happy wife happy life. Average speed mid sevens low eights.
Think for coastal SD boats the SeaKeeper is a good choice. Agree with Peter that for FD hulls fins may make more sense. At least with our program where skinny water is commonly involved fish make no sense. Like the idea of Magnus especially on the new LDL boats which will see mixed use. But again if crossing oceans is part of the program electric fins (Humphrees) would top my list. Less impact on space and less servicing as no hydraulics.
 
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Hippocampus said:
Totally agree for a FD hull fins are well protected in most grounding situations. But for many SD hulls and even more so for planing hulls think that’s not the case. Think that’s augmented by the occurrence of commonly running aground in settings where depth is rapidly changing.
Click to expand...

Even on my planing hull I think fins would remain within the hull/keel envelope. But as you mentioned, what kind of bottom you hit is a big factor in what parts of the boat you'll hit. Many boats (mine included) already have to be careful of that, however, as even with a keel, plenty of twins have pretty exposed props (mine are both exposed with not much in front of them and a few inches below the bottom of the keel).

Given a free choice of stabilization on my boat, I think I'd go for fins first, paravanes as a second choice. There's no good space for a Seakeeper, so that's pretty much ruled out for practical reasons. Fins would fit fine and be nice to have. Paravanes would be almost as good, provided the rig is easy to deploy / retrieve and can stow in a way that doesn't add a bunch of air draft. Realistically, the times where I'd want stabilization are mostly in deep enough, open enough water that dragging fish wouldn't be an issue, and at low speed (stabilization on plane would only be a nice bonus with fins, but I wouldn't consider it worth extra money).

Of course, when retrofitting any existing boat, there's always going to be the question of "what fits best?" Some boats will have a good spot for fins, others would require moving major equipment. Same thing with a Seakeeper. And some are more practical than others to mount paravanes.
 
Hippocampus said:
Totally agree for a FD hull fins are well protected in most grounding situations. But for many SD hulls and even more so for planing hulls think that’s not the case. Think that’s augmented by the occurrence of commonly running aground in settings where depth is rapidly changing.


Like that my engine room has enough space for access. Putting more stuff in to have the SeaKeeper run off the propulsion engine would mean more difficulty getting around the front of the engine. So from above post if I can find the space I can put in another small genset for ~$6k or increase the hours on the existing one meaning it will need replacement sooner. Don’t think the economics are much different and having another thing taking up space and needing service is inconvenient.
Our SeaKeeper is on the stringers that run the length of the boat. Minimal reenforcement was required. It’s midline under the center lazerette access hatch so we have full access to all sides of the enclosure, pumps and related paraphernalia from above and side hatches. Perhaps on larger boats retrofitting off midline is possible. But suspect on many boats in the 40-50’ range placing it on existing support structures with additional beefing up if necessary would make more sense. Usually that means midline or close.
For fuel usage think it does decrease range but so far in use has minimal impact. Genset is 3/4gph. But SeaKeeper is on when we’re doing 7-10k. When going faster it’s rarely necessary. Our main propulsion engine is miserly at 7-10k but fuel use dramatically increases at >10k. So if we run at 7-8K with the SeaKeeper on we are using much less fuel overall than running at higher speeds and are still very comfortable. Coming from sail 7k-8k is just fine with us. Just ran from Deltaville VA to NEB RI on 278g. Went against current lower NYC and alternated with and against throughout L.I. Sound. Minor chop except one day in L.I. Sound and through Block I sound. Then 4’. Happy to trade fuel for comfort as the wife could put things down without them moving and no need to hold anything when you moving around. Happy wife happy life. Average speed mid sevens low eights.
Think for coastal SD boats the SeaKeeper is a good choice. Agree with Peter that for FD hulls fins may make more sense. At least with our program where skinny water is commonly involved fish make no sense. Like the idea of Magnus especially on the new LDL boats which will see mixed use. But again if crossing oceans is part of the program electric fins (Humphrees) would top my list. Less impact on space and less servicing as no hydraulics.
Click to expand...
I don't think there is any "best" form of stabilization for any given boat. There are pluses and minuses to each so selection is dependent on intended use and personal preference. But when it comes to gyros, top-of-list benefit is some form of 'no holes needed' or 'no exposed fins to tear off.' Those are emotional appeals that conviently avoid 60+ years of data that clearly show probability of catastrophic failure is infinitesimallly small. You have a better chance of throwing a rod in a generator running a Seakeeper than snapping off a fin.

Peter
 
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