Comer Channel Tides

[mlibkind]

I want to transit from Thompson Bay (Long Island, Bahama) to Water Cay (Jumentos) through Comer Channel. With 6'3" draft I must do it at near high tide.

The closest tide station is Nassau. I have found two blogs with conflicting information. One said the tides at Comer Channel were 1.5 hours past Nassau. The other was not as specific, but said that the depths were very adequate for my boat's draft 2 hours before Nassau.

Given the shape of the tide curve, that's actually not that great of difference, but it would be nice to know the correct data. But certainly it would be worth knowing if the tide is rising or ebbing relative to Nassau.

Does anyone out there have any personal information about the tides at Comer Channel?

My best guess is that the high tide at Comer Channel is after Nassau, but it would be good to check this.

FYI, I'm trying to contact businesses at Thompson Bay thinking that they may have this information. So far no luck. If I find out anything I will post it.

[mlibkind]

THIS IS AN UPDATE

I transited Comer Channel twice in the last two weeks. Here is tide and depth information from those passages. Maybe it will help others.

Tides

First of all, I want to explain an experience I had in planning the passage. I was in California during the initial planning. I have 3 apps that can give me tide information. They differed greatly. Turns out that all but one gave the time with no reference to the time zone they are using. But one gave the time zone. It was EST, which is correct for the Bahamas. Turns out that two of the apps were using the time zone in which I was located when using the app. So be careful of that.

I used 4 tide locations from Garmin Bluechart Mobile (no longer available). Here is the the information I got for January 15, 2020.

Nurse Channel
Low 5:13 AM, -0.3 feet
High 11:20 AM, 2.4 feet

Clarence Harbor
Low 5:54 AM, -0.3 feet
High 12:01 PM, 2.9 feet

Long Island
Low 5:37 AM, 0.5 feet
High 11:58 AM, 3.0 feet

Nassau
Low 4:53 AM, -0.3
High 11:22 AM, 2.4 feet

I was told by an experienced Comer Channel cruiser (a dozen trips) that he found that Nassau time plus 40 minutes worked well. You can see that with that correction all the times are close enough to use with what I believe is some reliability for Comer Channel.

The height of the tides varies from location to location. That is to be expected. The differences did not make a difference for me.

Actual depth information for January 15, 2020 passage

Bluechart Mobile, which incorporates Explorer Chart data, gives the shallowest part of the Comer Channel at 5.6 feet. edThe draft of my boat is 6'3". My experience is that the charts are conservative and I might squeak by at low tide. But I still wanted some extra room. For the east to west crossing the timing of the tides is perfect and I planned my passage to be at the shallowest area at about noon. I should have 2+ feet of tide.

Here is what I experienced on the crossing.

During our passage through Comer Channel the lowest reading I saw on the depth gauge is 8.3 feet. Because the transducer is underwater with no offset, the actual shallowest I see about 9.3 feet. Assuming we passed through the shallowest area with 2+ feet of tide, the minimum depth at low water is about 7 feet.

On my return trip through Comer Channel on January 21, 2020, the timing of the tides was not good. If all went well, even at low tide I should be able to get through without grounding. But I delayed my departure from my anchorage to correspond to about 1-foot of tide at the channel. All went well.

Other information

Here are some other bits of information I gathered from the cruiser that told me about the Nassau tide correction for Comer Channel.

1. The bottom of Comer Channel is very silty and therefore any grounding will be very soft. He says that he has plowed through groundings, but I would not plan on that.

My recent experience confirms that the bottom is probably very soft silt. We had high winds while in the Jumentos and Ragged Islands. Both times crossing Comer Channel the water was milky and one could not see the bottom in even 8 feet of water while I could see the bottom in 25-30 feet of water on the Great Bahama Bank.

2. There can be local shoaling in the channel that is not indicated on charts. That might be what he "plowed through."

3. The depth can be different than what you calculate in high winds; the water can be significantly moved by the wind. I have no idea whether this is actually significant.

Coordinates for Comer Channel

These are the coordinates for the Comer Channel that I used.

Comer Channel East
23 deg 20.80' N
075 deg 19.87' W

Comer Channel
23 deg 19.50' N
075 deg 24.00' W

Comer Channel West
23 deg 20.25' N
075 deg 31.50' W

I hope that this information will help others planning to transit Comer Channel.

[Nightsky]

Thanks for this report even though I came across it 1 yr after your post. I am planning a trip to Water cay and eventually down to Ragged Island from Georgetown. Not sure I can make it in one day AND time the high water at Comer channel so was considering going to Thompson bay and leaving from there. Your post is exactly the kind of info I have been seeking. Do you recall whether or not you had cell coverage down there at all? My understanding is that Ragged island has btc tower. Cell coverage is needed for wx down loads.

[chris mac]

Originally Posted by Nightsky

Thanks for this report even though I came across it 1 yr after your post. I am planning a trip to Water cay and eventually down to Ragged Island from Georgetown. Not sure I can make it in one day AND time the high water at Comer channel so was considering going to Thompson bay and leaving from there. Your post is exactly the kind of info I have been seeking. Do you recall whether or not you had cell coverage down there at all? My understanding is that Ragged island has btc tower. Cell coverage is needed for wx down loads.

We just did that run about 3 weeks ago.
We went down thru Hog cay cut. Our buddy boat with 5' draft had no problem on 3/4 high tide.
We did come channel coming back up. No issues at all. Explorer charts were accurate.
Cell reception, good signal at Hog cay, at the top. Then hog cay at the bottom. Some say they get signal as soon as raccoon cay.

[Nightsky]

Originally Posted by chris mac

We just did that run about 3 weeks ago.
We went down thru Hog cay cut. Our buddy boat with 5' draft had no problem on 3/4 high tide.
We did come channel coming back up. No issues at all. Explorer charts were accurate.
Cell reception, good signal at Hog cay, at the top. Then hog cay at the bottom. Some say they get signal as soon as raccoon cay.

Thanks Chris Mac. I looked at hog cay cut on both navionics and aqua maps explore rcharts and decided I want no part of it. Perhaps if I was following someone with a known draft and knowledge of the route I would probably give it a go. Not on my own though for a first time. I see how that route would cut a day off our trip to water cay if I had the nerve or the experience.

[chris mac]

Originally Posted by Nightsky

Thanks Chris Mac. I looked at hog cay cut on both navionics and aqua maps explore rcharts and decided I want no part of it. Perhaps if I was following someone with a known draft and knowledge of the route I would probably give it a go. Not on my own though for a first time. I see how that route would cut a day off our trip to water cay if I had the nerve or the experience.

No problem going around either. If you are in a rush, then you're doing it wrong[emoji854]
And just to give some inspiration to head down there...
This is flamingo cay, loggerhead turtle swam right up to me. My wife took the pic off our swim step.

[Nightsky]

That is really cool. Hope we get so lucky.