Bridge panic

[psneeld]

Originally Posted by twistedtree

Just curious - does everyone know their air draft? We have a bridge here with an operator who we all fondly call the "bridge Nazi". He's constantly busting people's chops over not knowing their air draft. Lots of people want him to open when they can get under just fine. It's the second busiest draw bridge on the eastern seaboard, so I can understand his frustration.

Lots of places air draft doesn't matter at all, but in other areas, like the NY and Canadian canal systems, it matters a lot.

27 to top of antennas, 24 to top of mast, 17 to top of bimini, 13 to top of flybridge cowling.

Every bridge from NJ to Florida verfied and notes in cruising guide (as they are often wrong)...every note from changes in sceduled openings to tidal variations and actual measurement marker errors and "extra" nav height if bridge is not flat on the bottom.

No stopping for me if I don't have'ta...

[portager]

Originally Posted by psneeld

a small change in trim may affect that idea...

I would use a PC/104 based live video overlay board such as http://www.ampltd.com/dload/vmix104.pdf and integrate an inclinometer. The horizontal reference line could be adjusted in near real time (actual latency would be about 33 milliseconds). The PC/104 board stack should be enclosed in a sealed cantainer such as Tri-M Can-Tainer - PC104 Container/Chassis/Enclosure Designed For Hostile Environments to protect it from the marine environment.

If that is too complex, mount the camera on a small platform that rotates in pitch with a counter weight mounted below on a rigid arm so that the camera platform is gravity stabilized. Don't forget to include a viscous damper to eliminate overshoot.

[caltexflanc]

Originally Posted by markpierce

Usually to the former Kaiser pipe plant.

Really? Not into downtown by the Third St bridge? I hear they re-did the town dock up there. Used to make a great day trip, but I needed a designated captain. That was back when Copia was still open, but needless to say we hit a few other places downtown regardless.

The trickiest piece of navigation was right past the power lines after the bridgem where the channel swung around and the markers somewhat ambiguous, including the green in the middle of a mud flat.

[GarryP]

Originally Posted by portager

Another alternative could be to mount a small waterproof video camera pointing forward on the top of the mast and graphic overlay module that can generate a horizontal line at what ever pixel row you select. With a little calibration you could get the horizontal line to indicate the level of the top of the mast. That should eliminate the guesswork and provide a good lookout.

Actually, no marks or graphic is needed. With a camera on the masthead, it's easy to tell if you'll clear the bridge. As you approach, if the obstruction is rising in the video image, you'll clear; if it's not rising, you won't clear.

[markpierce]

Originally Posted by caltexflanc

Really? Not into downtown by the Third St bridge? I hear they re-did the town dock up there. Used to make a great day trip, but I needed a designated captain. That was back when Copia was still open, but needless to say we hit a few other places downtown regardless.

The trickiest piece of navigation was right past the power lines after the bridgem where the channel swung around and the markers somewhat ambiguous, including the green in the middle of a mud flat.

Beyond the old Kaiser plant, I'm leery to proceed without local knowledge. Also, Napa City doesn't have the money to dredge the turning basin and put in a dock.

The wide, lower part of the river, consisting of two "S" curves, is mostly very shallow, with navigation limited to a poorly marked, natural channel. One needs to not get closer than 50 to 100 yards from any channel marker and weave toward one marker to another as a straight course from one marker to another can/will make you scrape bottom.

Here's a short article on boating on the river. The dock at Napa downtown mentioned in the article was removed in 2005.

http://www.deltacalifornia.com/napa_river_info.htm

Edit: according to this article, the city now has the money to construct a dock.

http://friendsofthenapariver.org/

Another Napa River article:

http://www.boatingsf.com/article/cru...the-napa-river

[caltexflanc]

I was given to believe the dock is there now; it's been awhile but we never had issues past the turn off into the Kaiser plant with 4 ft draft. You could call Napa Marina or the Yacht club if you're paranoid (which is an OK thing to be in these matters)
I made this trip many times, but not for the last 5 years. It's fun, you go through the Carneros district for a good part of the trip which can be viewed from the flying bridge or by standing on top of the deck house of a non-FB boat.

Your links describe what I was saying exactly about getting through the wide section after the power lines.

Edit: just looked at a Google earth image dated 9/12.. no dock. All the other improvements and development are there, you can see the pilings from the old dock. Of course, you could just anchor out and dinghy or kayak over since the bridge marks the end of navigation. A guy in some sort of express cruiser did that once when we were there and there was no room at the dock. Or just tie up to the pilings if they are still there.

[bfloyd4445]

Originally Posted by Peter B

Yeah, he knew that. ,he was just looking for a 'scuse to post more pics of his fancy mast, eh Mark.

ye may have hit the nail, that mast is awfully busy wonder whats it doing?

[portager]

Originally Posted by GarryP

Actually, no marks or graphic is needed. With a camera on the masthead, it's easy to tell if you'll clear the bridge. As you approach, if the obstruction is rising in the video image, you'll clear; if it's not rising, you won't clear.

Good point, and it works regardless of trim.

[Northern Spy]

What an interesting place to boat. Just spent a little time on Navionics looking at charts. Now I understand why you call it the delta. Thanks for sharing.

[ARoss]

Originally Posted by Stelaine

His forestay melted too! Now THAT sounds painful, glad I don't have one. Thanks mom & dad.

aww.. and I thought TF had standards!!!

[FlyWright]

I just passed through there last Wed on my way back from 2 weeks on the Napa.





Wed morning, the fog was 1/4 to 1/2 mile visibility when I left the homes on Milton Rd. I thought it would burn off quickly but was surprised to find it less than 1/4 mile the entire stretch of the Napa including my approach to the Mare Island Causeway Bridge for an opening.

As I approached the Hwy 37 Bridge, it came into sight at about 0.2NM. Shortly after passing under Hwy 37, I made the initial call for an opening of the Causeway Bridge at 0.4NM without the bridge in sight. The bridge tender replied that he couldn't see me or the bridge traffic in the current thick fog, but to continue my approach and he'd advise. The bridge came into view at 0.17NM and I just held position north of the opening. After a minute or two, the bridge tender replied that he had me and the stopped road traffic in sight and verified my vertical clearance requirement. (It's actually 15'6", I fit in my 15' 8" covered slip, but I round up to 17' for bridge inaccuracies, my antennae and my own fudge factor.) With the fog as thick as it was, I was more focused on traffic anchored downstream on my radar than my vertical clearance. The tender assured me I had the room, so I proceeded, confident in his ability to perform his duties. I proceeded slowly, but was too busy to snap any pictures.

Further into the Mare Island Str the visibility picked up to close to a mile. Here is a shot from the Mare Island Straight as Giggitoni was texting me to watch out for fairies in the fog. (What can I say, this IS on the edge of the Bay Area!!)



As I passed the Carquinez Straight, the fog started to burn off and the sun poked through. I liked this perspective as I passed under I-80.



The final tally for the 2-week trip as I approached my marina:

[twistedtree]

Originally Posted by psneeld

27 to top of antennas, 24 to top of mast, 17 to top of bimini, 13 to top of flybridge cowling.

Every bridge from NJ to Florida verfied and notes in cruising guide (as they are often wrong)...every note from changes in sceduled openings to tidal variations and actual measurement marker errors and "extra" nav height if bridge is not flat on the bottom.

No stopping for me if I don't have'ta...

Now that's what I'm talkin' about

[angus99]

Originally Posted by Stelaine

His forestay melted too! Now THAT sounds painful, glad I don't have one. Thanks mom & dad.

We're all happy your parents were thinking <ahem> ahead.

The previous owners said it was like a stick of dynamite going off when they hit the power line, so it pays to know your air draft.

[Bilgewater]

FlyWright - What model is your Garmin? Looks like everything one would need is on one screen.

[caltexflanc]

Fly Wright, tell us more about the trip. How far up did you go? Looking at Google Earth and surfing the web, I could barely recognize downtown Napa along the river compared to the last time I was there, with all the new and redevelopment.

Don't you know you don't need radar in that area? You just stay put or anchor out in the channel when it gets real bad, so sayeth the "gurus" here....

[ancora]

My son was chief engineer on a container ship going into Port Chicago. Getting under the bridges was a matter of timing, having enough water under the keel and enough overhead clearance. Touch and go but they made it.

[FlyWright]

Bilgewater, my Garmin is a GPS128. It's an old non-mapping model with an externa antenna that came with the boat. I keep it for that summary page and its serial port feed that connects to an old backup laptop with navigation software if needed. It's also got a decent anchor alarm that I use regularly.

caltexflanc, I'll try to post a trip report in a new thread. Since the focus of the trip was fishing, I only ventured as far north as Rocktram. All nights were spent at a friend's dock on Milton Rd.

I was sure glad I had radar on that trip home. There were some anglers in a small aluminum boat anchored at the edge of the channel in the thick fog..no lights and no horns. Also, a guy was anchored just out of the channel immediately south of the Mare Island Causeway Bridge. My radar provided early warning of both of these guys. As it turned out, I was the only one operating in the fog with lights and fog horn. Even the 'professional' operators of tugs and ferries were dark and silent.

It was a great feeling to be able to traverse the hazards of the Napa River in near zero-zero conditions. Each time I find myself in that predicament, I learn something new about my environment, my boat or myself and build confidence in my boat's and my own abilities.

[Codger2]

Originally Posted by FlyWright

It was a great feeling to be able to traverse the hazards of the Napa River in near zero-zero conditions. Each time I find myself in that predicament, I learn something new about my environment, my boat or myself and build confidence in my boat's and my own abilities.

I call it "euphoria" and there's nothing quite like it! It happens to me every time I take the boat out as I learn something new every time! (And the fact that I've cheated death again,plays a big part in that feeling. )

[markpierce]

Originally Posted by FlyWright

... As it turned out, I was the only one operating in the fog with lights and fog horn. Even the 'professional' operators of tugs and ferries were dark and silent. ...

I'm proud of you, Al. ... Wish there was fog more often when I go out. Want to amortize the cost of my horns. I'm still in the "two digits per blast" range now. (First blast was four digits.) Thinking I'll start making three shorts when backing out of my berth. Never saw the need (almost all boats never seem to leave/enter their berths) until earlier this week when another boat was coming into its berth several berths away the same time I was backing out of mine.

Leaving tomorrow to explore Antelope Canyon, a tributary to the Grand Canyon (foot and boat trip). Will be back March.

[FlyWright]

Have a great time in AZ, Mark. I hope you don't make Perla do all the paddling.

Call when you return. Maybe I'll have a slip in your marina by then.