Boatnerd Discussion Forum

Check here - http://www.charts.noaa.gov/OnLineViewer/14911.shtml

US Army Corps of Engineers Project page, including the latest (2008) published depth survey in PDF format.

http://www.lre.usace.army.mil/who/opera ... rays_reef/

3 year old data for what its worth.

Most times that I went through there was on a light ship, and the last time I remember I was in the pilot house of the Wolverine, and looking down off the bridge wing on a sunny day, the water was pretty calm, but still some good ripples and wake from the boat, but I could clearly see the bottom and every detail through there, including some very large boulders on the bottom. We had to check back due to the squat and the heavy vibration, as most boats do. Even at the reduced speed there was still significant vibration, but far more managable than at full RPM.

Its not as deep as you think. We never go thought there any deeper than 23' 10" at datum. And footed never go thought loaded and when they do go thought upbound, they pump Alot of ballast out

I wouldn't go through there any deeper than 25' and then I check down because of the squat. There are some shallow spots at the south end. Most loaded ships avoid this passage and only go through there light ship.

As long as you stay in the channel, it appears that the depth is always deeper than 30 ft. I see mostly 36 ft depths with a few high spots. I have Chart #72 on the wall in front of me right now, and Inset B shows the passage in detail. Use a chart plotter or GPS with marine data as you travel and you can see where to stay in the channel and where you can cut corners in smaller (pleasure) craft. When we pass through I always keep at least 5-10 ft depth under the boat according to the chart plotter, so that I am usually covered if there is a boulder that has been moved by ice. We only draw about 5 ft or so when fully loaded with divers and gear so I stay in 10-12 ft or deeper and cut the corners to save time and distance.

Remember, even the footers go through this channel so you know it is deep enough for anybody.

Just wondering if any of the mariners on here know the exact deep in the Gray Reef Channel. I have to make a trip to Lake Michigan and was going down this way.


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