[clnewman]

I'm no nautical design engineer, and I'm hoping one of you designers that peruses this forum can answer these questions for me:

1. Would a draft of 4.92 ft. (1.50m) be unusually shallow for a full displacement hull displacing 83,725 pounds?

2. Is this light for a vessel with a LOA of 63.25 ft., LWL of 57.50 ft and a beam of 17.17 ft.?

3. Assuming a rounded bilge bottom, could one expect unusual pitch/roll characteristics, with no bulbous bow, but equipped with active stabilization?

4. How about roll when anchored, w/o flopper stoppers?

If you need more data to give an informed answer, drop me an email.

Thanks,

Chuck

[Loren Schweizer]

1) No
2) Yes
3) No
4) Yes

Seriously.

[AMG]

On nr 3 and 4, it also has something to do what is above, how many decks and in what material...

[clnewman]

Here's a rendering of the profile:



I apologize in advance if I shouldn't have posted the rendering here. Thought it would help.

We've just entered into a (very) preliminary discussion re: a possible build of this, and the shallow draft (compared to the draft of similar sized displacement vessels I've come across) sticks in my head as a potential issue. However, the price is definitely right, so it's worth looking into further.

It's supposed to be all FRP construction. I don't have comprehensive specs yet, so I don't know about the overlays, thicknesses, etc. They're supposed to be coming today.

We can always add flopper stopper booms (perhaps just 1, not sure) during the build process.

The light weight also gives me concerns about righting ability in the event of a knockdown. From my understanding, there's only 1500# of ballast in the keel.

[AMG]

The righting ability should be no problem, as long as there is no water intrusion.

For stability a couple of bilge keels could help.

When I look at the stern extension it appear as this boat is designed to have a bulbous bow? But whatever, S&S use to know what they are doing, so there is no reason for concern I think.

[clnewman]

S&S does have a good reputation, so am assuming all is well with the design. I just received a profile drawing of the vessel, and it shows a bulbous bow. My mistake before.

I discussed bilge keels with the designer, and he says there are no current plans to implement them. Hull #1 is just out of the mold. If we buy, we'd be hull #2 or #3. Unfortunately, there won't be time to have a sea trial on #1 before #2 goes into production.

The builder is Queenship, in a yard in Zhuhai, China. Apparently they're now OK financially. Does anybody have any recent feedback (good or bad) on them?

[AMG]

About bilge keels, on a GRP yacht they are not as easy to fit as on a metal hull so I should probably not try. There must be a center keel anyway which also helps at rest. Another option that you can retrofit is a mast with a small sail if you should experience too much rolling. It could actually be removable and stored on deck.

My experience with Far East production is that they are using a little too much material, making the yachts heavy. But with a displacement yacht this may be just favorable.

[clnewman]

A stay sail is indeed an option, as are downrigger booms that not only handle flopper stoppers at anchor, but paravanes while underway.

As far as too much material goes, this vessel only displaces around 42 tons, so I don't think they're using too much material. If anything, perhaps not enough. Am still awaiting hull material/construction specs.

[AMG]

If it isn´t built yet, you don´t know the final displacement...

About paravanes, maybe useful at rest, but underway I wouldn´t use them on a pleasure yacht. I have heard horror stories on incidents when they must be recovered in heavy weather, they can both hurt yourself and crash through portholes or windows...

[clnewman]

This is true... all specs are estimates. However, I was quoting their preliminary "estimate" for (lightship) displacement. That said, the quoted 4.92' draft is a lightship estimate, too. However, with the hull design as it is, more draft due to higher displacement means less freeboard. A Catch-22, yes?

I saw The Perfect Storm, too... and have no desire to have paravanes come crashing into my pilothouse That would ruin my entire day.

Originally Posted by AMG

If it isn´t built yet, you don´t know the final displacement...

About paravanes, maybe useful at rest, but underway I wouldn´t use them on a pleasure yacht. I have heard horror stories on incidents when they must be recovered in heavy weather, they can both hurt yourself and crash through portholes or windows...

[Loren Schweizer]

I am 100% with Lars-- flopper stoppers will, at the very least, remove meat from your hands, if not whole fingers, over time.

They are, in this modern age of bow thrusters and the like, an anachronism and a royal pain in the @ss to deploy--usually when it has already gotten snotty.

Get some active fin stabs and pay close attention to the square footage recommendation; if in doubt, get the next size up.

[clnewman]

Am not too concerned about active stabilization... the vessel comes with Wesmar RS9000s with 9 sq. ft. fins... so am good to go there.

My original thought was the use of flopper stopper discs (as opposed to paravanes) for use while anchored/moored.

[JWY]

Am chiming in here a bit late, but agree with the comments already posted: negative on added bilge keels on fiberglass, negative on flopper stoppers even the discs at anchor (go with an "at anchor" active fin stabilization system).

The righting ability of the vessel may be affected by any flexing in the hull at the time of rollover as relates particularly to the windows which may relate to AMG's comments about water intrusion. A staysail that would be large enough to be effective, along with the mast, adds significant weight on the upper deck and combined with davit,dinghy & engine may created a different roll issue.

Although it has "rounded bilge bottom", is there any mention of chines?

Judy

[cranky]

Active stabilisers require lots of energy therfore one would need a generator running to provided hydrolic power 24/7 On a 60 ft displacent vessel it should be possible to be at anchor for 12 hours running on batteries alone ( assuming one uses the correct equipment ) In this case flopper stoppers are the best option.

Yes deploying and handeling flopper stopers can be dangerous to the careless or inexperianced but they do work, even better when underway.

[Loren Schweizer]

Hate to disagree, cranky, but stabs actually require very little power, at least in running mode ( 8 kts ).