Stabilizing systems compared

[skyhawk]

How would the ride compare between the various stabilizing methods that could be used on a MV and say a "typical" catamaran SV?

I'm thinking in terms of both ride while underway but also at a typical anchorage.....
Obviously some systems only work while underway, etc....

 

[mvweebles]

Not sure I am answering the exam question, but I can tell you that a friend with a Horizon Power Cat 52 - a very nice boat - would probably go back to a Naiad stabilized monohull. It's sort of stable, but a bit jerky. At-anchor is of course nice. I have flopper-stopper booms on both sides of my FD trawler which work very well.

I've been aboard his boat for a few 100+ nm runs. It's fine, but I to slightly prefer a stabilized monohull.

I've run a couple boats that had both fins and paravanes. Both are effective, and each have their pluses and minuses. Long range cruising favors fish. Shorter duration trips favor fins. I have no experience with gyros so cannot comment.

Peter

 

[Insequent]

Not sure I am answering the exam question, but I can tell you that a friend with a Horizon Power Cat 52 - a very nice boat - would probably go back to a Naiad stabilized monohull. It's sort of stable, but a bit jerky. At-anchor is of course nice. I have flopper-stopper booms on both sides of my FD trawler which work very well.

I've been aboard his boat for a few 100+ nm runs. It's fine, but I to slightly prefer a stabilized monohull.

I've run a couple boats that had both fins and paravanes. Both are effective, and each have their pluses and minuses. Long range cruising favors fish. Shorter duration trips favor fins. I have no experience with gyros so cannot comment.

Peter

I think that's about right.

A couple of years ago I was in the shallow waters around the Keppel Islands and bobbing around a bit even with my Naiads on. Then I looked over and saw a sailing cat having quite a wild ride (under power), both pitching and rolling. At the time thought to myself "so a cat is not always the answer then"

 

[skyhawk]

how would you compare your 'ride' with flopper stoppers at anchor to the cat anchored next door?

 

[mvweebles]

For me, my tip to tip beam of the flopper stoppers is about 28 feet. She's very flat at anchor, about the same as a cat. California coastal anchorages are mostly open roadsteads with frequent swell sets that invade the otherwise tranquil settings.

A decent flopper stopper setup is in the $4k-$5k range by the time everything is purchased and mounted. Not exactly cheap, but a helluva less than a paravanes setup engineered for underway usage.

Really depends on intended usage.

Peter

 

[Insequent]

how would you compare your 'ride' with flopper stoppers at anchor to the cat anchored next door?

I don't have flopper stoppers, yet.

We were both heading into a marina, neither of us were anchored or wanting to try and anchor given the conditions. My guess is that in an anchorage with some protection from wind/waves we would ride about the same if I did have flopper stoppers.

 

[AusCan]

This is an interesting option that I haven't seen before.

It can be used at anchor or underway. I like the simplicity.

 

[socalrider]

This is an interesting option that I haven't seen before.

It can be used at anchor or underway. I like the simplicity.

Any more info on that installation? I've been watching the Vendee globe so they look quite familiar!

 

[AusCan]

Any more info on that installation? I've been watching the Vendee globe so they look quite familiar!

No details. I just saw them on this boat advert.

https://yachthub.com/list/boats-for...n-long-range-aft-wheelhouse-grp-vessel/257617

I love the boat, but not the price tag.

 

[socalrider]

No details. I just saw them on this boat advert.

https://yachthub.com/list/boats-for...n-long-range-aft-wheelhouse-grp-vessel/257617

I love the boat, but not the price tag.

Interesting - I wonder how effective that would be in practice. Seems like not a whole lot of surface area for such a large vessel. If effective, it seems like a pretty cool solution compared to paravanes.

 

[jimdavi]

The Waveless fins look interesting. All electric, draws ~2kw I think.

 

[hollywood8118]

Interesting - I wonder how effective that would be in practice. Seems like not a whole lot of surface area for such a large vessel. If effective, it seems like a pretty cool solution compared to paravanes.

Those wings have a lot more area than paravane fish. I was always impressed how my less than 3 sq. ft paravanes (X2) kept a 60000 lb full displacement boat from rolling excessively. Its all in the generated lift.
HOLLYWOOD

 

[Simi 60]

This is an interesting option that I haven't seen before.

It can be used at anchor or underway. I like the simplicity.

Rogers and Lough do the batwing setup
https://rlmarine.com.au/stabilisers/

Nice boat, big fiberglass put her up here a while ago
https://www.trawlerforum.com/forums/showpost.php?p=948774&postcount=9630

 

[skyhawk]

so that wing...is it actuated, or am I understanding it correctly in that it only effectively makes the boat have a wider beam?

 

[socalrider]

so that wing...is it actuated, or am I understanding it correctly in that it only effectively makes the boat have a wider beam?

It's passive - effectively a removable rolling chock as far as I can understand (admittedly not far)

 

[DDW]

The wings work by supplying hydrodynamic lift opposing the motion as long as you are moving. They might have a slight dampening effect just due to the flat plate drag at anchor. There was a scholarly study done in one of the Canadian maritime colleges you can find online, testing the fins against fish. Fish were slightly more effective at the cost of more drag. Big bonus of fins was ease of operation (and installation).

Something that could be done very cheaply in many trawler designs (at the time of build) would be to install a long centerboard. I've never seen it done though. It can be quite effective on sailboats, even at anchor. It works just like the fins.

Rolling chocks also supply hydrodynamic lift while in motion, but are more like the lifting strakes on jets. They have a lot less leverage around the center of roll.