Long and Maybe a bit OT, Santee navigation

So I bought a Tracker 175 last month and two days after getting it took it down to Lake Marion. Went into Stumphole with raised motor and idled to the places I've found these last few years back in there. No problems. Pretty slow fishing so decided to go to Jacks Creek, where I've never been because I've never felt entirely comfortable on that bigger water in my Gheenoe. Long story short, I got out of the river channel (which I think is poorly marked) and realizing I was in 6 feet of water, slowed to just above idle but didn't raise the motor and hit a stump at less than 10mph destroying my prop. It took 2 hours to limp back to Stumphole landing, and a trip to Columbia to get a new prop and salvage the weekend trip.

Can someone clarify the navigation hazards, specifically the rock piles, at either end of the canal? Also, I understand red and green navigation bouys, but do not understand the poles with square placard on top, some with numbers, most with nothing.
If I'm not mistaken, on most lakes an underwater obstacle is marked with a white buoy/orange diamond. I realize as well, that Lake Marion is one big underwater hazard and no way can they mark everything. There are rock piles on each end of the canal and on both sides as I understand. A friend told me if going from the canal to Moultrie, "Don't get out of the 'lane' because there are rock piles just under the water. On the other end, outside of the canal toward Harrys near the Marion dam there are several markers that say "ROCK" but is that it? Do those poles identified only with a number indicate an underwater hazard?

Is there any newer maps or software that offers some level of safe navigation or am I missing something, or is that just the hazard of fishing the Santee lakes?

I've puttered all over up in and near Stumphole in my little Gheenoe with a 9.9 hp but suddenly feel helplessly in danger of prop and engine damage in this newer boat. Yet I see people running at speed in bass boats, center consoles, deep V's etc. Am I missing something obvious?

The posts with squares and numbers are the channel markers. Basically the one you are at, aim for the next one. The clear channel is narrow and VERY curvy. Very easy to get out of it. Navionics is very close and you could probably follow it. If you don't have it you can even download their boating app on your phone.Attachment 462421

As you mentioned.....lakes can become very dangerous to your equipment. IMO nothing replaces time spent on the water "learning" the areas you are fishing in. A good depth finder with maps is CRUTIAL marking underwater obstacles. In my lakes the red and green markers mark the river channels (green is Ga/red is SC). The creek channels are also marked in creeks full of submerged timber.

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Originally Posted by hobbz

The posts with squares and numbers are the channel markers. Basically the one you are at, aim for the next one. The clear channel is narrow and VERY curvy. Very easy to get out of it. Navionics is very close and you could probably follow it. If you don't have it you can even download their boating app on your phone.Attachment 462421

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I know when heading upstream keep the red markers on the right, green on left and mark the original river channel. But you're saying the poles with squares and numbers are channel markers as well. Do you keep these markers to the right or left depending on going upstream or down? Or if you're aiming from one to the next you're okay as long as you pass close to them?
On the second day there I did get the Navionics app on my phone which is helpful in following the river channel. But I'm still confused as to the rock piles at either end of the canal. Thanks for the info!

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Originally Posted by gabowman

As you mentioned.....lakes can become very dangerous to your equipment. IMO nothing replaces time spent on the water "learning" the areas you are fishing in. A good depth finder with maps is CRUTIAL marking underwater obstacles. In my lakes the red and green markers mark the river channels (green is Ga/red is SC). The creek channels are also marked in creeks full of submerged timber.

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You mean a depthfinder with map built in correct? I've been looking at upgrading to a side scan Garmin 7 or 8 but for another $100 bucks I can get the map version. Certainly cheaper than a prop, or worse, a lower unit. I guess at either Santee lake, it's just a good idea to raise the motor any time you're in water less than 10 feet deep. Although I've not yet been in Moultrie, my understanding is, unlike Marion, Moultrie WAS mostly logged before flooding. I need to go to Santee sometime and forget fishing, just find some safe passages to places I want to fish, like you said. Hard to drive 4 hours and not fish though!!! Thanks for the help!

Ive gotten to where I wouldnt run my boat without maps (GPS) on anymore. The maps shows you soooooo much...creek/river channels, submerged timber, etc. Even when trolling you can see when youre coming up on a shallow point so you can adjust course before getting too shallow. And alot of times my longlining involves following the creek channels which are also marked on the maps. Theres so many people that just doesnt realize how shallow theyre running their boats/props when they dont kave a depth finder with maps.

The rockpile I know of on the canal is man made and plenty deep enough not to be a hazard. It's there, along with the rocks at the top of either side, to be a fail safe should one dam or the other fail, to hold water in the other lake, as to not completely drain both lakes. That's how it was explained to me anyway.

I've bought and installed a new Garmin Echomap UHD 93sv. I've been wanting a side view sonar, figured I'd get the 7 and didn't really need the maps, but gabowman makes sense and the maps are at the very least, handy to have. Bass Pro had some of the last generation 93's on sale, and family had given me a BP gift card so I pulled the trigger.
Of course I had to get a Ram mount, which is awesome by the way! Everything is installed and working and I am itching to get on the water with it. I think this (4th of July) weekend is not the time though, so I'm gonna have to itch a while before scratching.
I realize the map won't ID all underwater obstacles but certainly will be helpful in following channels and for monitoring water depth BEFORE I wander into shallow water. Helpful for fishing AND navigating. Can't wait to try the side scan.

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Originally Posted by TreednNC

The rockpile I know of on the canal is man made and plenty deep enough not to be a hazard. It's there, along with the rocks at the top of either side, to be a fail safe should one dam or the other fail, to hold water in the other lake, as to not completely drain both lakes. That's how it was explained to me anyway.

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The day after destroying my prop on upper Marion as described in the OP, we went to the canal. Where the canal opens up into Marion I saw boats fishing near one of those markers on the left. Later we ventured up near there, idling along to see if we could see what it was and hit something with my new one day old prop. Wasn't like a stump, figured rock and sure enough had small chips along the leading edge. Thank goodness we were barely moving but still, rough on the motor.
So.... I don't know.
But as you exit the canal it's on the left, near the first marker. Further up Mac's and Harry's is on your right and there ARE some markers that say "ROCK". I'm going back down in July and I may venture up to near that spot and using side scan, see if I can see just what is where. I intend to spend some time in that area NOT fishing just trying to learn the water.

To start, invest in a stainless prop. Secondly, get a CMC kick up jack plate. These two items will allow low speed stump strikes without damage to either prop or motor. Marion can be hazardous, but there are many many safe lanes to run on speed. Any time you exit the river channel the water depth will shallow. This doesn’t mean you can’t run on speed, you just need to know the safe lane. There are three well marked lanes into Jacks Creek, the first two will need to be learned by watching others or going with someone that knows them. The third can be ran on speed by anyone. Go to channel marker 132 in the river, hang a left staying centered in creek, water will be 5 to 6 feet to start but most importantly stump free.

Google “Navionics Web App”. It will allow you to view Navioncs lake mapping on your computer or phone without paying a fee. It obviously does not show stumps but it does clearly show the boating lane exiting the canal and other marked boating lanes. Good thing to study before you go. You can also get the Navionics app for your phone and use it on the water to help with navigation.

Also, it’s not a great idea to idle around with the motor looking for boating obstacles. You will find them with the motor, just like you experienced. Raise your trolling motor way up and ease in and check if you must.

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Originally Posted by 91tiger

Google “Navionics Web App”. It will allow you to view Navioncs lake mapping on your computer or phone without paying a fee. It obviously does not show stumps but it does clearly show the boating lane exiting the canal and other marked boating lanes. Good thing to study before you go. You can also get the Navionics app for your phone and use it on the water to help with navigation.

Also, it’s not a great idea to idle around with the motor looking for boating obstacles. You will find them with the motor, just like you experienced. Raise your trolling motor way up and ease in and check if you must.

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Yeah I got the Navionics app for a while now. I can see the usefulness of it, particularly following channels as you mention. It's also a great compliment to the new Garmin and checking contours, creek channels, points, etc. in most all the lakes around.
And to clarify, no, I wouldn't go looking for specific stumps and rocks with the main motor down. If there's something specific like the Santee rock piles I'd ease up with the trolling motor.

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Originally Posted by Bigtrout

Yeah I got the Navionics app for a while now. I can see the usefulness of it, particularly following channels as you mention. It's also a great compliment to the new Garmin and checking contours, creek channels, points, etc. in most all the lakes around.
And to clarify, no, I wouldn't go looking for specific stumps and rocks with the main motor down. If there's something specific like the Santee rock piles I'd ease up with the trolling motor.

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I've never used mapping on the Garmin but there does seem to be a push by the depthfinder manufacturers to provide much more accurate mapping. Lowrance came out with their CMap card which my understanding is they sent out teams to survey the lakes and create ultra high resolution mapping. I've never used it for Santee because I haven't fished there in years but it is unreal how good it is for Hartwell and Murray. But unfortunately it isn't accurate at all for Greenwood, Navionics is way more accurate there. But it may be worth talking to the local bass guys at Santee and see which card they like best for there. If you see one with three 12 inch screens at his console that's probably the one to ask. The bass guy I know that fishes Santee regularly really likes the Lake Master chip form Hummingbird but I don't think he has tried the Lowrance Chip there.

I have the Garmin ECHOMAP UHD 93sv. At Bass Pro I asked the guy about it. It comes with Garmins LakeVU maps of pretty much most inland lakes, and the GT54 transducer. I asked him why one was on sale and the other was almost twice as much. The one on sale is about 5 years old, discontinued to be replaced with a newer unit, and thus marked down. The newer unit has the newest GT56 transducer and Navionics. I asked about the difference between LakeVu and Navionics. He said LakeVu was Garmin's own lake mapping but that Garmin had bought Navionics and added it to their new units. I asked if one mapping had a definite advantage over the other. His response was, "Nah, not really". I decided to save the money and get the older unit and figure it is adequate for my needs.
And I figure the best one can expect at Santee anyway, is using mapping to mark the established channels. Well, and like any other lake, channels, dropoffs, humps, or other underwater features in the deeper water.

I used my new Garmin on Greenwood this week, rather extensively just to learn the basics. First it is awesome. The only thing I need to work on is tweaking the color/contrast/brightness to see the objects on SideView. I see the shadows clearly but have a difficult time seeing what is casting the shadow.

The other thing I noticed specific to mapping. I was looking at a place on Greenwood where a side creek channel joins the main channel. The Navionics app on my phone, and the mapping in my unit showed the same bottom contour, however, they did not show me in the same position on the lake. Close, but not the same. Cannot say for sure which one was off but could have been one or the other was updating GPS signal at the time. I'll check that again to see if it's consistent or just happened at that point.

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Originally Posted by Bigtrout

The other thing I noticed specific to mapping. I was looking at a place on Greenwood where a side creek channel joins the main channel. The Navionics app on my phone, and the mapping in my unit showed the same bottom contour, however, they did not show me in the same position on the lake. Close, but not the same. Cannot say for sure which one was off but could have been one or the other was updating GPS signal at the time. I'll check that again to see if it's consistent or just happened at that point.

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The few times I have used my phone app, the GPS position was not super accurate. You wouldn't want to use it to run a narrow stump lined channel like in the upper end of Clarks Hill.

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Originally Posted by 91tiger

The few times I have used my phone app, the GPS position was not super accurate. You wouldn't want to use it to run a narrow stump lined channel like in the upper end of Clarks Hill.

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Good to know. I have noticed on the phone app, if I'm trying to hit a specific point, the position icon sometimes stops moving then jumps or turns. Kinda glitchy like. I assumed that was the phone GPS updating the signal. May be the cause of what you speak of.

Be careful with ANY mapping, especially before you verify it, but I know of one lake in SC that Cmaps shows being 20-24ft deep, that's actually several acres of flats with stumps in it, that can even be seen via google earth/maps. I've alerted them about a year ago, but no change. Not that Im aware of anyway. I don't have a subscription to it, but use their web ap, and it's been down a while since their security breach a few weeks ago.

I may be totally off base here but I believe most maps that show lake bottom contour are based on topographic maps. So that would mean using topographic maps before the creation of the lake, since topographic maps were made using aerial photos, which were updated only after a period of years, and wouldn't detect lake bottom contours after creation of the lake. Something could have changed drastically between the last update and closing the dam to flood land. Siltation and erosion could be a huge factor in lake bottom changes.

I don't know if satellite imagery is used today, or if some technology exists that DOES actually map the bottom, like sonar soundings, etc. I'd have a tendency to trust Navionics most, since it IS specific to water navigation. That said, we used to navigate lakes BEFORE we had any type of mapping software, just using our brains. Which, at the end of the day, is our first and last line of defense.

I see many a boats running at speed in 5-6 feet of water. I always figured they just didnt know how shallow it really is. NOT what I wanna do though!:yikesSantee can be EXTREMELY dangerous to navigate if you dont know the lake.

Broad river from the mouth of cooter creek is shallow to the bridge. It becomes almost unnavigable when the hill falls below the 5 foot level. Many years ago it was right at 50 ft deep under broad river bridge. Now it is lucky to make 8ft when full pool.

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Originally Posted by gabowman

I see many a boats running at speed in 5-6 feet of water. I always figured they just didnt know how shallow it really is. NOT what I wanna do though!:yikesSantee can be EXTREMELY dangerous to navigate if you dont know the lake.

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Yeah, so have I. I've seen some serious sized center console, deep V boats running up towards Stumphole. There is one place up the river, before getting in the river proper, it gets extremely shallow. I don't know how they get on the river unless they just churn mud.

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Originally Posted by Ttexastom

Broad river from the mouth of cooter creek is shallow to the bridge. It becomes almost unnavigable when the hill falls below the 5 foot level. Many years ago it was right at 50 ft deep under broad river bridge. Now it is lucky to make 8ft when full pool.

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Yeah, exactly. Point being, I think we all have seen lake bottoms change drastically over the years, particularly at the mouth of creeks etc. due to sedimentation. Just wondering when or even IF the lake mapping is updated to take this into account.