stabilizer use in quartering seas

[Docs Holiday]

On a recent trip into the Gulf of Mexico-I experienced following seas (only 3-5 feet) which pushed the boat through and arch of about 60 degrees-the stabilizers were active and the boat rolled through the same degrees-very difficult to control and keep on a direct heading and basically threw ev eything inside-including the double door refrigerator into the middle of the galley. I tried speeding up (thats when the frig flew) which made things worse and going 9 knots did not alleviate the situation-in retrospect should I have deactivated the Seabrace stabilizers? or is there a problem with my stabilizers?

 

[Nonchalant1]

If you are in following seas, it can move water under the boat faster than you are going. This actually makes the stabilizers work in reverse! The fins try to correct the first samll roll and water mooving from astern against the fins makes the roll worse, so the fins move farther out, which makes the roll worse. This can be a dangerous situation. Speed will overcome it if that is the problem, but turning them off will too. You have to go faster than the water can move from astern.

Doug Shuman

 

[Genesis]

Turn 'em off in those conditions.

I don't know the specifics of your boat but Gigabite pretty much required an active hand on the wheel in following seas to keep her reasonable.

I did not have that sort of problem running her in those condtions - a 60 degree swing is HUGE and would have totally freaked me out!

 

[mike]

If you have the Niaid orig gyro system, and assuming they are functioning properly, you should have deactivated the stabilizers. The orig 2 axis gyro system is not capable of reacting to those conditions. Their new 3 term gyro cures the following-sea problem. Check out their web site for the details. The upgrade replaces the std gyro with accelerometers that senses all three axis and adjusts accordingly. It’s about a $15k upgrade, but worth it if you do a lot off offshore boating.

 

[doc g]

THe price is`25K for the "upgraded" electronic control.........Pat

 

[ThirdHatt]

THe price is`25K for the "upgraded" electronic control.........Pat

Naiad told me a couple of weeks ago that the COMPLETE system (model 252) with the upgraded electronic version is about $22k. Then ~$5k for various hoses, hydraulic fittings, plus installation($$$).

 

[Angela]

Interesting discussion....when we were still boat shopping back in January, we looked at a 58' YachtFish in Miami that had seen a lot of seas. We were reading their logs and found that these boats were very difficult to handle in following seas. There were many places where we read about the refrigerator taking a stroll, and the salon furniture rearranging itself while they were sitting on it, but the most stunning entry I read was on one from their trips either to Jamaica or Trinidad (can't remember which trip it was) where the boat actually spun around in a complete 360-degree circle before they were able to regain control - it did that TWICE. The owner who was driving at the time, said the stabilizers kicked in at some point and it was a very violent correction.

We also saw indication that that hull had taken some serious stress as the aft bulkhead in the master stateroom had separated from the side of the boat, but that was the only place where we saw anything like that. That YF brought her passengers home safely more than once, and that was the most important part. By the way, they had a deadline by which to get back to the States, and therefore, they did not wait for their best days at sea. For me, I'm not sure there is anything I just have to get back to that would make me go out on seas like that on a bad day. That's what airplanes are for if you must be elsewhere by a date certain.

 

[Docs Holiday]

Thanks all who replied --I will definitely turn off the stabilizers next time! Anyone know if Seabrace has an upgrade similar to Naiad's?

 

[Genesis]

I can't see where these boats could be THAT different in terms of their hull than my 45. She was interesting to handle in a following sea, but I wouldn't call it difficult or dangerous - just requiring a personal hand on the helm and an intelligent choice of operating speed. Running fast enough to crest a following sea and come into the next trough can be dangerous; I did it with moderate size seas in Gigabite, but you'd have to be nuts to do that in really big stuff - that's just begging to get sideways.

Any boat can be put at risk of a broach in a following sea. You can make it far more likely if the tabs are extended (at all), which they should NOT be in these conditions. Stabilizers are troublesome in these sorts of conditions because the water is flowing the "wrong way" from what they expect, so they can make things MUCH worse.

My biggest fear in really BIG following seas is that if you got broached you're exposing the salon windows to waves that could break on them, and that can sink you fast. Anything small enough to not present that threat isn't a sea state that should cause this kind of misbehavior.

I never rearranged the salon or galley in the time I owned Gigabite - and we got caught out in some really awful conditions more than once......

 

[Angela]

I believe those folks were in some really big stuff. The owner commented that they didn't have time to wait for better days at sea and just went on through it. So, it sounds like they crossed in conditions that they otherwise would not have. Still, I wouldn't do it - there is no deadline that important to me. In that trip, the water pump got ripped off the wall and thrown across the engine room. That's pretty violent. As nervous as I get about little stuff around here (never lived on the ocean until now), I would not have lived to tell about it had I been on that boat, because I would have had a stroke and died! But then again, I would NOT have been on that boat out there in THAT. Pretty telling...some of the other folks aboard that boat during that trip did fly home.

What I appreciate about what they did was knowing that a Hatteras can take that, albeit maybe not in every situation, but it is interesting to see just what one can take. Makes me feel even better about being a Hatteras owner. Don't try that with a Sea Ray or a Carver.

 

[Pete]

Our boat is a 48 LRC with the four fin version of GyroGale stabilizers. 3 to4 foot seas on the stern quarter is a fun ride on the boat at 8 knots with the waves rolling under the boat. I have the autopilot driven by a laptop and it holds the course without a problem. Just a slow up and down motion as the waves pass under us. I have been travelling with other boats in such conditions, and they have had to disengage their autopilots in these conditions to regain control. It may be the round chine displacement hull design, the large and deep keel, the stabilizers, or a combination of all of them. But it works great. Even when the waves are moving faster than your boat, the body of water is not moving, the wave progresses by transferring the energy through the water. Thus the stabilizers are still going through water as your propellers are in a forward motion.

Pete

 

[Capt K]

Years ago, there was a 53ED on my dock. I used to think that was one of the nicest boats around. Never guessed I would have something close to it a few years later. It was only occaissionally chartered out, usually during the off season for New England. One spring, it was coming back from Port Lucaya. The captain said a front was coming, but it was way off and moving slowly so he left along with a fairly large sport fish. They were of different speeds, etc, so they agreed to meet later on during the trip north.

Needless to say, the front sped up and caught them in very bad conditons. The expensive galley appliances and some of the granite countertops moved around the boat during this crossing. They lost the flybridge bimini top and the two jet skis along with the tender. He stated that he could not use the stabilzers due to the horrendous following sea conditions. More than once, he was bracing himself (feet first) against the salon windows while trying to keep the vessel in the proper orientation to avoid broaching or capsizing. This is the worst he and his mate (wife) ever encountered but they said they were never really worried about losing the boat. Just scared to death. To this day, he is a strong believer in a Hatteras.

Oh, yeah, never DID hear from the other boat. He figures it turned back or ran for it ducking into another port. The Hatt arrived at the expected location!

K

 

[jim rosenthal]

Agreed, but I am with Angela on this, I would stay in port and miss whatever deadline was going to pass. Old mariners versus bold mariners, but, sooner or later, no old and bold mariners.....
We had a recent run on my boat where we got caught out in occasional 5-6 footers; did okay and nothing smashed, but good and scared. A 36 foot boat does not feel big at all in those conditions.
The discussion about following seas and waves moving versus the water itself is interesting. Wave theory is that the energy moves through the medium causing motion up and down but that more or less the medium pretty much stays where it was on a longitudinal axis. (So in theory it wouldn't make a difference- the stabilizer fin would still see water going in the direction it was designed for. It's hard for me to believe that a following sea would equate to an eight or nine knot current going with the boat, although a current of that strength would easily be able to spin the boat around.)
At least that is what I was taught in college physics which is now a while ago- physic has a whole different meaning since I went to M.D. trade school. I am going to ask the owners of Playpen (56 LRC) what they think about using stabilizers in following seas; I think they have Naiads but I am not sure. I am curious to see what they say.

 

[Genesis]

I've been out (unintentionally) in 8-10s with a few 12s and 14s thrown in for good measure. That trip made a believer out of me in terms of owning a Hatt.

I never felt we were in danger of having the boat go out from under me, and we didn't even empty cupbords. Absolutely zero damage, and not a drop of water anywhere inside either. There was not a square millimeter of the exterior of the boat that was not wet, however. I, personally, was soaked. My biggest fear was taking a true breaker onto the forward windows, which likely would have been catastrophic. It didn't happen but you can bet I was VERY aware of the risk. The interior of the fridge was rearranged, but the latches and hold-downs on the unit itself held. This is, by the way, one reason I really like the 45C's fridge location and anchoring - it faces inward rather than fore and aft and mine was blocked VERY stoutly to the cabinetry - for it to come loose the entire galley would have to basically be ripped loose from the hull.

How do I know they were 8-10s with a few 12s and 14s? Well, I was on the flybridge and I couldn't see over the top of the waves! Seeing that the boat had a published 12' height above the waterline and my head is a good 2-3' above that, well, do the math......

I wouldn't go with that forecast on purpose, but if you fish offshore far enough for long enough it will happen to you. When you're 100nm offshore and port is 6 hours out in decent conditions when things start to deteriorate rapidly you're insane to run for port - you'll end up having to cross the bar in those conditions and THAT's a good way to lose the ship......

 

[luckydave215]

Unless the waves are breaking, the water moves in a vertical circular path. Only the wave front (pressure wave) moves througn the water, the water mass stays where it is. It's similar to wave energy in air (sound). The air isn't blowing at you, even standing right in front of the speakers at a Rolling Stones show, only the pressure wave is going past.
If the waves are breaking, the part of the wave that falls over the top is the only part of the water mass that moves laterally (and not very far), not the major mass of water.
To see this yourself, float your rubber ducky in the bathtub and make some non breaking waves. You will see the circular motion.

Lucky Dave
Instrument Design Engineer
Scripps Institution of Oceanography

 

[SKYCHENEY]

I've had my 53ED in 10 footers, but not a following sea. I also would not go out in this intentionally, but they built all day until that is what we were faced with. I was not fearful in the least and the boat handled them very well. As far as the stabilizers go, the worst following sea I have been in is about 5ft. I kept them turned on and didn't really feel any adverse effects. The autopilot did wander a bit, but not enough to turn it off and take over. I think that in most cases, the old 2 axis Naiads do a great job. I have thought about upgrading, but for 25-30K, I think I'll leave them alone.

 

[Ross Macdonald]

In a trip down to Mexico last year, We had good weather intel from Nets on the SSB and used weather routing service out of NY. As you all have mentioned, deadlines are trouble. We sat in Cabo San Lucas for 8 days waiting for a window to head North back to San Diego. Everyone we talked to on the radio or in person that got their butts kicked had a deadline to meet. We have 9 sq. ft. Wesmar stablilizers on a 60 Hatt enclosed bridge. They were put on by the previous owner and are way over-sized for the boat. In a 350 mile run down from San Diego to Turtle Bay (Half way point from SD-Cabo) we encountered 8ft following seas. We had to hand steer for about 6-7 hrs. If this happens this year, I'll try putting the stabs in stand by. It is extremely stressful running in these conditions in pitch black for 8-9hrs down the outside of the Baja peninsula. You have to literally drive the boat by feel and try not to oversteer. In a stiff head sea the stabs don't prevent the up and down motion, but in beam seas, and some quartering conditions they work well. I agree with the comment on the difference between a full displacement hull and the hull shape on most Hatt Sportfishers. Following seas would seem to be handled much smoother in the displacement hull. We always run the boat at 10-11 knots on these long trips just to extend range. This being said, our hull doesn't do well in big following seas....