To stabilize or not to stabilize?

kraftee said:

To use Lou Codega's words: It "platforms" the waves in conditions like that - in accordance with the laws of physics.

Click to expand...

i.e., it rolls, just like a planing hull boat. And as Delfin points out, fins will counteract that.

Delfin and Twistedtree,

I am not trying to win you over to "my side" - or pick a fight with you. The OP asked about 45-50' FD boats and whether to go with additional stabilization or not. I merely suggested that not ALL boats BENEFIT from additional stabilization - and you guys decided to refute my statement. But I'll say it again: A Great Harbour would not BENEFIT from additional stabilization. For many reasons - not least of which are the problems created by mounting fins. Fortunately, the naturally stable hull design allows them to travel safely in conditions that would REQUIRE external stabilization on most round-bilged boats. As to whether that motion would be preferable to that of a round-bilged hull with working active stabilizers? Personal preference and real-world comparisons might best determine that. But it would have to come from someone with a lot of sea miles on both types of boats. I can tell you that I have been subjected to those "12' beam seas" that Delfin mentioned for an extended passage offshore on a Great Harbour N37. It wasn't much fun. But I am pretty sure it wouldn't have been any fun in a Nordhavn/Krogen/what-have-you with active stabilizers either. Of course, absent or with malfunctioning fin stabilizers, I would question the ability of any round-bilged trawler to maintain that beam-sea heading.

I understand that you obviously have strong feelings about the style of hull and stabilization on your boat. No problem there. I am pleased that your choice of boats works so well for YOUR style of cruising. I am not trying to change your mind in any way. But there are other folks, like the OP, who may have legitimate questions about which type of hull might be best for THEM. In that case, denigrating the path Great Harbour has chosen to go with their hull - and with no practical experience on that style hull is doing a disservice to the Forum. But then, I'm just a salesman.

psneeld said:

It is hard to believe that ANY vessel at some point doesn't have an improved ride from some sort of stabilization.

Sure a hull can be designed to reduce that need...but as has been said...at some point roll is inevitable.

There are other types of stabilization that could possibly be used other than active fins...but I can't say for sure without further study.

Click to expand...

Paravanes would be an option I suppose, but I doubt would make much sense cost wise given the way these boats are typically used.

kraftee said:

Delfin and Twistedtree,

I am not trying to win you over to "my side" - or pick a fight with you. The OP asked about 45-50' FD boats and whether to go with additional stabilization or not. I merely suggested that not ALL boats BENEFIT from additional stabilization - and you guys decided to refute my statement. But I'll say it again: A Great Harbour would not BENEFIT from additional stabilization. For many reasons - not least of which are the problems created by mounting fins. Fortunately, the naturally stable hull design allows them to travel safely in conditions that would REQUIRE external stabilization on most round-bilged boats. As to whether that motion would be preferable to that of a round-bilged hull with working active stabilizers? Personal preference and real-world comparisons might best determine that. But it would have to come from someone with a lot of sea miles on both types of boats. I can tell you that I have been subjected to those "12' beam seas" that Delfin mentioned for an extended passage offshore on a Great Harbour N37. It wasn't much fun. But I am pretty sure it wouldn't have been any fun in a Nordhavn/Krogen/what-have-you with active stabilizers either. Of course, absent or with malfunctioning fin stabilizers, I would question the ability of any round-bilged trawler to maintain that beam-sea heading.

I understand that you obviously have strong feelings about the style of hull and stabilization on your boat. No problem there. I am pleased that your choice of boats works so well for YOUR style of cruising. I am not trying to change your mind in any way. But there are other folks, like the OP, who may have legitimate questions about which type of hull might be best for THEM. In that case, denigrating the path Great Harbour has chosen to go with their hull - and with no practical experience on that style hull is doing a disservice to the Forum. But then, I'm just a salesman.

Click to expand...

I guess you don't see the distinction between "would not benefit from" and "can't be accommodated". And while I can't speak for TT, I feel no particular need to defend the proposition that stabilized vessels roll less than unstabilized vessels. I was just correcting a statement that some vessels wouldn't benefit at all from stabilization of whatever form.

If the OP chooses a GH, or Manatee or Florida Bay Coaster he will no doubt love it because they are great boats. I doubt, however, that if he is in the beam seas that you encountered that you said was no fun would be seen by him as loads of fun, nor would he probably say that under those conditions it wouldn't be nice if the GH could be stabilized. Again, there is a difference between "can't" and "valueless".

Finally, having been in lots of beam seas of the size you encounter off Vancouver island I can tell you that Delfin is quite stable although the fins work hard. But then again, that is what active fins do - reduce roll to make the ride far more comfortable than it would be without.

Signing off.

I do understand the meaning of the word "Benefit". Benefit, loosely stated means to "be useful or helpful to". Adding potentially 3' more draft and/or 6' more beam, additional cost, additional complexity and two appendages to snag anchor rodes, pilings, the bottom, etc. would not be useful or helpful to the use of a Great Harbour! Would they make the ride slightly better in a very limited range of conditions that many GH owners will never see? Perhaps. I am not sure without actually testing that under real world conditions. But to be of overall benefit to the boat. Nope. Pretty sure on that one.

People sure get their panties in a knot over the weirdest things.

The person who's dreams gave birth to the Great Harbour series wanted a boat for coastal cruising and to cruise up the Amazon River. I invite Delfin to follow a Great Harbour N37 up the Amazon, and we'll see which is the better designed boat.

MurrayM said:

People sure get their panties in a knot over the weirdest things.

The person who's dreams gave birth to the Great Harbour series wanted a boat for coastal cruising and to cruise up the Amazon River. I invite Delfin to follow a Great Harbour N37 up the Amazon, and we'll see which is the better designed boat.

Click to expand...

You may have lost the plot here Murray. The question was not whether or not a shallow draft vessel is superior to a deep draft vessel in shallow water. That one I think we can all figure out without too much controversy. The question was whether the statement was correct that some vessels in the ocean cannot have their resistance to roll reduced by stabilization. That proposition would be false.

The question of whether some vessels, because of design, are unfit for some purposes should also be uncontroversial. The GH is unfit for stabilization and Delfin is unfit for gunkholing in 2 feet of water. Using the logic offered, the fact that Delfin cannot manage shallow waters should allow me to say that some vessels, like Delfin, can't benefit from shallow draft. And that would be about as silly as contending that some vessels have no need of stabilization under all conditions.

MurrayM said:

People sure get their panties in a knot over the weirdest things.

Click to expand...

So right, Murray, but here's two "real world" experienced boaters that know their vessels well. The verbiage used is hair splitting, and both points of view are logical. Any vessel abeam upon the surface of the water without a substantial enough ballast to plum the vessel vertical against the urge of enormous forces to lift one side of a boat while the other is plowing and loosing buoyancy at the same moment, the vessel would tend to yield to the angle of the wave over the average of its bottom shape.

If a vessel is at a 20 degrees Starboard angle on the front side of a wave and 15-20 degrees to Port on the backside of a wave, most of us would call that a roll (it sure feels like it), but depending on the frequency, a round bottom hull may roll several more times in the cycle. If some roll resistance is built into the design, those extra cycles of rolling between the waves are likely to be less. I've been side by side with an un-stabilized KK 42 when such a beam sea was present. I was rolling twice between wave cycles but was pretty flat when I hit the valley. He never stopped rolling during the entire period. On the other hand, I was reaching 30 degrees on the front side of the wave sometimes, and I doubted he ever reached 20. A half-hour later I turned back, legs exhausted from the movement in my relatively high helm position. Next day it was 2 ft. on the beam and really stretched out. Rock, rock, splash, and it was done.

When I think of the hull shape, beam, and draft of a GH, I believe it must be highly resistant to rolling cycles even while "platforming" over beam waves. I'm no Naval Architect, but I am an engineer, and in consideration of the leverage forces it would take to additionally stabilize such a heavy vessel (twice the weight of my Manatee over nearly the same length) in a beam sea, sheww.....even if you could get wings on it, they'd probably break off, and with paravanes, the fish and rigging would need to be so massive as to make them impractical.. A gyro...maybe if it was built in at the factory and not an add on. A roll-resistant design becomes the enemy of add-on stabilization. I wouldn't want to place that kind of torque on any hull that I owned. No benefit that I can see.

Thanks to Delfin and Kraftee for those provocative points.

There are gyro stabilizers and the tubes that extend and rotate (forget the name for the moment...where's RickB when you need him?) beyond fins and para's.


I still can't think of any hull I have ever seen that didn't roll at some point...and I have landed on many and hoisted to countless others.


It may not be practical based on economics or other reasons...but not because the GHs don't roll at some point.

What I was getting at is that while you may venture offshore with Delfin in conditions abeam which test your vessels design capabilities, another person with a Great Harbour would probably be anchored or exploring protected thin waters, waiting for conditions to moderate.

While sea kayaking the BC coast my wife and I heard all manner of doomsday stories about how we would never make it...crossing from the mainland to Port Hardy being one example. We waited a couple days for a break in the weather, and made the crossing by camping on the Deserters Group, paddling into Port Hardy the following day. Flat calm both days. Light rain. Killer Whales. Awesome.

An example with our Sundowner Tug would be the day we came out of a calm anchorage to see huge whitecaps rolling down Grenville Channel, so we turned around, anchored again, and spent the day photographing ashore.

My point being you wouldn't follow a Great Harbour up the Amazon, so why expect a Great Harbour to follow you into huge rollers abeam offshore?

psneeld said:

...and the tubes that extend and rotate...

Click to expand...

One example: RotorSwing

Yeah, about two years ago, I was up at Snead Island Boatworks and saw a huge Krogen on the hard that had something like those tubes sticking out of it. I imagined it must have been for stabilization, but didn't know how they worked. Thanks for the link.

kraftee said:

Not trying to pick a fight, just giving my opinion, based on about 10,000 nm aboard unstabilized GH's in all kinds of conditions.

Click to expand...

You can invite me along anytime
I'd love to see this for myself

To the OP--- Given the potential conditions you can encounter in the kind of boating it sounds like you want to do, I think if you can find a boat that you can afford that has active or passive stabilizers that are installed correctly, you will be happier with that boat than the same boat without stabilizers. Or, if you find a boat that you like but doesn't have stabilizers, if you can afford to have them installed correctly, it will prove to be a good investment.

However... if you find a boat that suits your purposes to a "T" but doesn't have stabilizers and you don't want to pay the cost of having them installed, it will not automatically mean that you won't enjoy the boat. You may need to mind weather and sea conditions a bit more carefully, depending on the boat's characteristics.

Our old 36' boat doesn't have stabilizers and installing them on a boat of this type would not be a viable expense in our opinion. Doesn't mean we wouldn't like a boat with stabilizers, or perhaps even prefer one once we experienced it. But it also doesn't mean we can't enjoy the boat we have to the fullest.

If it was us in your position, I think we'd try out boats we liked with and without stabilizers, ideally in the kinds of conditions we'd be likely to encounter. Beg rides or charter, but I think a boat of the type you are contemplating is too large an investment to base on assumptions, second-hand information, or opinions. These can help, of course, but in the end it's a decision you need to make yourself. Which to me means you want the most first-hand experience you can come up with.

All the forum posts in the world won't tell you what you really need to know, which is do YOU like the action of a boat with stabilizers, and do YOU like the action of a boat without stabilizers? Until you can definitively answer those two questions, you're just guessing.

healhustler said:

Yeah, about two years ago, I was up at Snead Island Boatworks and saw a huge Krogen on the hard that had something like those tubes sticking out of it. I imagined it must have been for stabilization, but didn't know how they worked. Thanks for the link.

Click to expand...

I'd never seen those before. I suppose you could install them on a flat underbody, since the orientation of the tube doesn't seem like it would have an effect on stabilization. And, you could retract them for those trips up the Amazon! But doesn't it seem like there would be a fair amount of drag in this system? I'm also trying to visualize how you manage the forces of very rapid deceleration. Do they each rotate in both directions, or only one with each rotating in a different direction? Unclear from what I saw, but a very interesting idea.

Yes, they would rotate both ways, and at various speeds depending on roll. Here's a simple explanation, with extra whiz-bang ($$$) over engineering for stationary stabilization:


What I like about this idea is if they are transom mounted (they would swing out when in use) they wouldn't effect ones ability to sneak through shallow waters.

Marin said:

To the OP--- Given the potential conditions you can encounter in the kind of boating it sounds like you want to do, I think if you can find a boat that you can afford that has active or passive stabilizers that are installed correctly, you will be happier with that boat than the same boat without stabilizers. Or, if you find a boat that you like but doesn't have stabilizers, if you can afford to have them installed correctly, it will prove to be a good investment.

However... if you find a boat that suits your purposes to a "T" but doesn't have stabilizers and you don't want to pay the cost of having them installed, it will not automatically mean that you won't enjoy the boat. You may need to mind weather and sea conditions a bit more carefully, depending on the boat's characteristics.

Our old 36' boat doesn't have stabilizers and installing them on a boat of this type would not be a viable expense in our opinion. Doesn't mean we wouldn't like a boat with stabilizers, or perhaps even prefer one once we experienced it. But it also doesn't mean we can't enjoy the boat we have to the fullest.

If it was us in your position, I think we'd try out boats we liked with and without stabilizers, ideally in the kinds of conditions we'd be likely to encounter. Beg rides or charter, but I think a boat of the type you are contemplating is too large an investment to base on assumptions, second-hand information, or opinions. These can help, of course, but in the end it's a decision you need to make yourself. Which to me means you want the most first-hand experience you can come up with.

All the forum posts in the world won't tell you what you really need to know, which is do YOU like the action of a boat with stabilizers, and do YOU like the action of a boat without stabilizers? Until you can definitively answer those two questions, you're just guessing.

Click to expand...

Very relevant comments - thank you. I am probably going into this without enough practical experience on these boats with and without stabilizers. I will try to get more experience. Also, I am leaning towards stabilizers and the boats I currently have in my sights have them. If I get tempted by one without, I'll have to make sure I do enough due diligence before I make a decision. Part of the problem is timing things to get the boats out in the kinds of conditions where stabilizers may really matter. Many of the boats I'm looking at are in relatively protected waters and getting them offshore won't be that easy.

Richard

Here's part of an email we received from a Kady Krogen 39 owner who had traveled from the Great Lakes to Trinidad plus spent several years cruising in the Caribbean with out stabilization. They added paravanes at a cost of just under 15K. They contracted the entire build/installation in Trinidad.

...We are also finding there is a large and steep learning curve to the paravanes. Things like launching and re-covering the dinghy, or re-covering and launching "the birds". Underway they are very close to a miracle. As you described, Larry, they seem to slow things down. The biggest difference I see is that the initial roll "down sea" is slower, but the "re-bound" is nearly non existent. We have been in beam seas with them that would have us running for cover before. At anchor, the characteristic roll Caribbean anchorage is far more comfortable. Bottom line....we like 'em!!

A friend that is a big boat captain was looking at a yacht for a client that had rotoswing stabilizers. He did a bunch of research on them and they do have a lot of fine attributes.. the biggest one is they can tuck back and that they work really well at anchor.

If you are going offshore on any boat that has less than two hulls all forms of stabilizers will help make the ride more comfortable.. even the barge like Florida Coasters and others of the same shape.. how they are carried out is the big question.

HOLLYWOOD

Delfin said:

I'd never seen those before. I suppose you could install them on a flat underbody, since the orientation of the tube doesn't seem like it would have an effect on stabilization. And, you could retract them for those trips up the Amazon! But doesn't it seem like there would be a fair amount of drag in this system? I'm also trying to visualize how you manage the forces of very rapid deceleration. Do they each rotate in both directions, or only one with each rotating in a different direction? Unclear from what I saw, but a very interesting idea.

Click to expand...

Nor had I wonder what they cost installed

Britannia said:

I did get one dissention as a PM - but still the numbers are overwhelming. The point made about being higher up on the boat was particularly telling - that would make roll far less tolerable than on a sailboat when one is at or near the waterline.

Click to expand...

Can confirm mouse on a broomstick theory. I work 90 feet above the water on a 140' tug, and let me tell ya, it can be one hell of a ride up here. The closest I've ever come to being seasick has been in this little sky box. Once it was so bad that the only relief I could find was to lay flat on the deck for a few minutes at a time. But then, at the end of my watch when I head below, it's practically pleasant sleeping weather.

Larry M said:

Here's part of an email we received from a Kady Krogen 39 owner who had traveled from the Great Lakes to Trinidad plus spent several years cruising in the Caribbean with out stabilization. They added paravanes at a cost of just under 15K. They contracted the entire build/installation in Trinidad.

...We are also finding there is a large and steep learning curve to the paravanes. Things like launching and re-covering the dinghy, or re-covering and launching "the birds". Underway they are very close to a miracle. As you described, Larry, they seem to slow things down. The biggest difference I see is that the initial roll "down sea" is slower, but the "re-bound" is nearly non existent. We have been in beam seas with them that would have us running for cover before. At anchor, the characteristic roll Caribbean anchorage is far more comfortable. Bottom line....we like 'em!!

Click to expand...

That is pretty much our experience also. Did it for $10k in Miami.
Our system seems simpler to deploy and retrieve, as I can deploy in a few minutes and retrieve just a few more, less than 10'

Also, easy for me to adjust, both underway and at rest.

Our system seems simpler to deploy and retrieve, as I can deploy in a few minutes and retrieve just a few more, less than 10'

Description , drawing , photo, video?

Alfons

Sir,
No Fins, no parafans or whatever, just get a Seakeeper Gyro. It cant get better then that! Sailboats are completely different and not comparable to Power. No work to be done with a gyro. Just switch it on!
I went through rough seas in Asia on Sail and Power. With a Gyro everyone on board wonders how comfy it is on a power boat even in rough conditions.
Alfons
Ps. you may have bought one already when you read this. Good on you. You never regret the expense.

Greetings,
Welcome aboard.

Wxx3 said:

That is pretty much our experience also. Did it for $10k in Miami.
Our system seems simpler to deploy and retrieve, as I can deploy in a few minutes and retrieve just a few more, less than 10'

Also, easy for me to adjust, both underway and at rest.

Click to expand...

Richard: I don't think you have seen the set up on the KK39. A different design/designer than on Hobo. We can also deploy and retrieve in a few minutes.

The difference in the cost is most likely in the fit and finish. He used SS compression posts vs. rope or wire. The poles are all painted. He went with a yacht finish.

Question: What conditions do you find it necessary to adjust the paravanes while underway?

I love my Naiad stabilizers and gave kept my dinner down more than once, just make sure if you buy a boat with them that they were serviced in the past three years or budget $3k to get the fins removed checked and the seals replaced .

Good luck

gwkiwi said:

I love my Naiad stabilizers and gave kept my dinner down more than once, just make sure if you buy a boat with them that they were serviced in the past three years or budget $3k to get the fins removed checked and the seals replaced .

Good luck

Click to expand...

Costs us about $1300 for 7 ft Wesmars. Schedule it during a bottom job haulout. Top notch yard does it.

THD said:

Eric-you posed my question-Where would stabilizers be installed on the GH hull? My understanding in that they should be somewhere around 30-35 degrees below horizontal to be most effective. I see no way tht could be done on the GH hull. that makes it a moot point as to whether the boat would perform better or not.

Click to expand...

Not exactly: Seakeeper Inc.

I'm of the opinion that stabilization is a big plus for ANY boat. The best type of stabilization may vary depending on your boat, and it may not always be cost effective; but it can always be improved one way or another.
No one has perfected the hull for all sea conditions; not even GH.

I've got bilge keels and sails for stabilization, but there are times when that is not enough.