Handling a Large Wave

[Discovery]

Discovery here,

Boat D in the above problem. Actually we were the third boat over the wave, due to our close proximity to the container ship. I would have attempted to move further away from the ship, but a sailboat was directly in front of us, and had stalled out (lost the wind due to the shadow of the ship. I could only turn starboard, toward the ship and hold on. We were about 150" from the ship as it passed. The front of the wave was 6' to 8', and the trough was 10' or more. the second wave followed by 15' to 20', and then the third wave after. We hit at 35 to 45 degrees, and stepped over one hull at a time (Discovery is a TC255 TomCat). The starboard bow dipped a little, and picked up some water. The only problem was that the starboard window was open about 4". I radioed that I just got my feet wet. We turned to look at Dora~Jean as she took the waves. As Steve said he fell into the trough and hit on the starboard quarter, plowing under, then shot into the air, and then fell into the second trough. Quite a show.

Don't know if I could have done anything different, under the circumstances. The sailboat left me nowhere to go. I saw Saltly-C's escape, but missed Pounder's head on approach.

Actually have a pix of the Container Ship approaching us. Maybe with time I can figure out how to link it.

Brent

[Dora~Jean]

Thanks Brent and Dixie (Discovery) I thought maybe I was exaggerating on the size of the wave/trough, but guess not according to your description. You know the feeling when something catastrophic or life-threatening occurs? -- everything slows down...I remember this wave at about 30 frames a second in my mind!!

Larry (Nancy H) I agree that on certain waves (non-breaking) it would be easiest on the boat and crew to turn tail and reduce the impact speed and allow the wave to pass under, I'll have to try it someday if I ever encounter another one of these 'generated' waves.

One thing is clear though, testament to the durability and stability of these boats. Not sure a deep-vee would have been quite so forgiving during the roll portion. After owning 7 other ocean-capable deep and modified vee's, this boat is hands-down the most controllable, comfortable, economical and stable I've ever owned, bar none.

[Discovery]

Here is an attempt to post the pix of the ship--although from this view it looks benign and far away. The ship bagan to turn and accelerate right after the pix was taken but my photog lost her cool and didn't get another shot.




I got it in, but I don't know how to change the size?! For a larger view, look in the Cygnet album.

Brent

TyBoo edit:

Brent - you did the link perfectly, but to get the bigger shot you need to click the thumbnail so it will display the full or "sized" pic, and then do just what you did with that version.

[SeaSpray]

This is a great thread for learning from shared experience. I have been near ships in the bay and the delta but never encountered waves as bad as these. I will be more aware in the future. Sure glad everyone come out okay.

There are a couple of things to keep in mind with large ships. They must maintain a certain amount of speed to maintain control of the vessel. I am not saying that this vessel was not going too fast but we don't know. If it was with the current it may have needed higher speed for control. Maybe he should have been under tug control.

I don't know for sure but I think there is a speed limit for ships in the bay. There is a Vessel Traffic Safety facility located on Yerba Beuna Island that keeps track of all ships in the bay. The ships are also supposed to stay in certain traffic lanes unless they have permission to do otherwise. You can listen to VTS and the ships talk on the VHF to find out what they are doing.

There is another thing to consider with big ships and something I have experienced. If you are in a channel or river when a ship comes by you can see it is pushing a lot of water in front of the bow. That water has to come from somewhere. If you are near the bank (between the ship and the shore) as the ship comes by, the water level will drop quickly and maybe by more than a foot. If you are in shallow water you could hit bottom. Then the stern waves will come along. BTDT

Steve

[Pete in NY]

I hope you guys don’t mind if an easterner chimes in.

I have been tracking my son Mike who is working on the Polar Adventure as a cadet observer, a just shy of 900ft tanker transporting crude between Valdez and the west coast. In doing so I am getting a new perspective on what it is like today from the bridge of the big guys. When I say track, I mean from my laptop in my living room. I have found public web sites to the AIS (Automatic Identification System) that show real time or near real time location of ships and larger harbor vessels in San Francisco, Seattle and Valdez so I can see where my son is at. GPS and identifying course, speed, name, call sign etc. info is broadcast from the ships to base stations. This is the law, it is mandatory for larger vessels. The Coast Guard monitors the real time versions of these signals continuously on computer screens (as well as on harbor stationery radar) and it is all interfaced. If a radar target pops up and no AIS info an alarm goes off. If the vessel is going too fast or off course another alarm and a call on the mandatory radio to the bridge or greater response. This could mean fines and sanctions against the licenses of the officers in charge if they don’t follow the rules. The professionals have more reason to follow the law since their job is at stake compared to the general recreational boater.

I checked the chart for the Oakland Bridge area and it is clear that there are dogleg channels for the big guys on either side of the bridge. Their turn would be predictable. Since the shipping channels are marked or noted on the chart as “vessel traffic services area – see note ‘D’ “, it would be prudent to avoid these when planning a trip or operating there. If you see a large ship you can also reasonably predict their course by looking at the chart. I have observed in NY harbor and its approaches that all the big guys and commercial barge traffic use the same courses and speeds as dictated by regulations. I should also note that the vessel pictured likely had a harbor pilot on board directing speed and direction to maintain the legal distance between him and the other big guys.

This predictability can mean safety for us C-Dory types since we can anticipate what the big guy will likely do and can avoid them like any other navigational hazard.

Getting back to the topic: I was amazed by my experience in 6 – 10ft square closely spaced (20-40ft between peaks) breaking wind waves on my CD25 crossing LI sound on a course perpendicular to 35knot E-NE winds and wind waves (beam sea). My course was parallel to the waves. Since the hull is shallow, about flat and the windage above the water quite high, the force of the water doesn’t transfer to the boat and the waves slid under the boat harmlessly. It seems that the wide beam and large reserve buoyancy above the waterline keeps the boat from rocking port and starboard very much like one might imagine and the wind pressure on the house windward side also steadies any rocking. There was never any feeling of imminent capsize since the boat only leans over so far, side to side and the waves just slide underneath. The ride parallel to the waves was much like that on a sailboat just going up and down in a beam sea and heeling a bit. I also did not have to slow down and maintained a 15mph speed. The boat did not rock like a round bilged trawler type hull or deep vee. I am certain that if my course would have been to windward that I would have had to slow to displacement speed or less since the bow has less reserve buoyancy up front and tends to bury into oncoming waves when plowing into them. I regularly stop or go very slow if a big wake is coming head on and the boat just floats up and over. With little or no way on the boat behaves like a corked bottle and just floats up and down. I am confident that nothing scary would happen in anywhere from bow on to beam on waves. Stern to waves of bigger stuff or rear quartering I don’t have any experience on the CD25 yet.

I’d be interested to hear from someone’s experience in bigger following or rear quartering seas since I have not done that yet and my imagination might be scarier than the actual experience and I won't go downwind in bigger stuff yet. Also, how does the boat behave without power in scary rough conditions?

[oldgrowth]

[Byrdman]

Yes... do share the site as to allow us this/these sights...humm.

[Pete in NY]

AIS sites:

http://www.aislive.com/AISLivePortal/DesktopDefault.aspx?tabindex=0&tabid=1

http://www.sealinks.net/US.htm

http://mxais.sfmx.org/bas/login.aspx?ReturnUrl=%2fbas%2fDefault.aspx

http://www.sailwx.info/shiptrack/index.html#search

The different sites give various detail. The color changes if they are anchored or underway. You need to register on some sites for the free/basic service. Realtime more detailed tracking costs bucks.

My Maptech navigator pro has the ability to track realtime AIS signals on the boat from my laptop but I don't have a receiver. On the big guys they can all see each other. If I was boating in a busy harbor like Seattle I'd consider looking into a transponder to show my boat or at the very least have a high quality radar reflector.

I use these sites to update myself on my son's location so I know when he might be in cell phone range. While they were anchored in Port Angeles I was able to talk to him on the bridge while seeing his ship on this webcam in realtime:

http://www.portangelesinn.com/webcam.html

He described the bridge as being like the starship Enterprise with multiple high end redundant systems with backup upon backup. The ship is steered by joystick that controls twin engine rooms and bow thrusters from a central better than Stidd type chair on tracks that can be adjusted for and aft 10ft or so. All systems are redundant and if they go off course more than 3 meters all sorts of alarms go off. If no one answers the alarms on the bridge an alarm goes off in all the officers quarters as well as a general alarm on the entire ship.

Isn't technology grand!

[Jim Gibson]

Brent-

Thanks for providing the picture and the quanitative description of the size of the wave. Helps really put it in perspective for everyone.

[Smuttynose]

I am amazed with this site. The simpliest question gets dozens of responses. I want to take the wave question to the next height. Do C-Dorys capsize? Send me to the right thread if I am missing it.

[JamesTXSD]

Pete, thank you for your perspective. It is educational and exciting for us to hear about how the CD-25 handles those conditions. We did our research for quite a while before heading to the SBS to see one of these in person. There's always that concern, no matter how much you research, that: did we make the right buying decision? It is great to hear another owner's perspective.

I expected many of our sailor friends to balk when they heard we were making the move from sail to C-Dory, but it has been quite the opposite - we are finding SO many of them who are familiar with the qualities of the C-Dory that make them so enticing to sailors... including how they ride in the sea conditions that started this thread.

Thanks again for your input.

Best wishes,
Jim B. (tick, tick, tick... counting down the days )

[TyBoo]

[KenMcC]

That ship had every right to increase its speed in that outbound situation. The speed limits are strictly imposed inbound, but not outbound (beyond certain points).

All of the answers, in my humble opinion, are wrong. And the primary reason is that it looks like you were all caught by surprise.

If you found yourselves dealing with a bigger wake than you had expected, or had even noticed, you may not have been totally aware of what was happening around you.

I learned as a 16 year old kid to avoid the two converted PT boats going in and out of the Ocean City (NJ) inlet, since they set up a huge bow wake. I learned, only because I was fascinated with the big boat, and was paying no attention to its wake. It was only when my Dad pointed out that I was watching the wrong thing, that I ran like hell away from the wake, since it was to big to head into for our little boat. Additionally, my brother and I used to go out into the shipping lanes, catching the southbound freighters and tankers out of New York Harbor. Those wakes were huge, so we learned to stay away, since they are displacing huge amounts of water.

I think the prudent thing to do is to avoid them altogether. There are two sets of rules, and both of them are written:

There are the "Rules of the Road", and there are the rules of dealing with big ships. The whole point is to stay away from the big ships. Especially when they are well underway.

FWIW

Ken

[gljjr]

[Dora~Jean]

Ken, I hear you about being lax on what's going on around you, I try my best to stay ahead of situations. This tanker came up essentially around a corner and at the time was going quite slow, well within manageability for all of us. Then as that sailboat crossed it's bow and stalled (they were far too close to attempt to cross its bow) the options began to narrow because it became another object to contend with in an increasingly tight area. The tanker accelerated and turned sharply (towards our exit path), I've never experienced a tanker accelerating that much in such a short distance. Possible it WAS trying to maintain control as Pete said or simply stayed slow to allow that sailboat to clear then gunned it.