Aquacscan MC-5

[Andydiversa]

Hi all

I'm apart of a team of technical rebreather dive based in Cape Town, South Africa. Team Underwater Explorers

We have a Aquacscan MC-5, with the logging interface and GPS connection on to a Garmin GPSMAP 168 sounder we also have Lowrance HDS7 Gen2 on the boat. The original owner was using it in the UK, so before it came out to us we had the tow fish replace and tuned to run is South Africa. The tow fish has a 100m cable on it.

We want to use it to find steel shipwreck to dive.

Where we are in South Africa, Cape Town we know there as a lot of steel ship sunk but not found yet. We are looking mainly for shipwreck in the 10m-60m arrange but could go deeper.

We have used the mag a few times over a shipwreck we dive regularly but could do with tips and tricks of the art of finding shipwrecks

Like, how fast you tow the fish?

What direction to tow the fish?

How do people do there search patents?

How to read the data after wards and maps to dive afterwards?

Any other tips your willing to give us, will be usefully as we are very much beginner at this stage.

Thanking you all in advance

Andy

 

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[ropesfish]

I am sure that you have seen the spec sheet (http://www.divetheworld.com/library/Mag/Mc5_Spec_0602.pdf) and the factory manual for the unit, which is pretty comprehensive. For those interested here is the link: http://www.aquascan.co.uk/HB_MC5_PES_PET_iss6_Mar08.pdf

Here are links to a book on my Google Drive that might help you < https://drive.google.com/open?id=0B31cEOWT4L3XaXhmZ0FoWEQzSFE >
The other option is to talk to Jim Whitaker <[email protected] > or Jason Nowell and ask them for assistance.

 

[Salvor6]

Hello Andy, we usually tow our Proton 3 mag in a north to south direction. We go a little over idle speed (about 3 knots) since the delay is two seconds. Try to get the mag as close to the bottom as possible. More advice to follow.

 

[Andydiversa]

Ropesfish got the Aquacscan info but will have a read of google drive.

Salvor6 how do you know how much cable to let out for the depth you are searching at?

Appreciate help guys

Andy

 

[ScubaFinder]

You will get tons of good advice here, but there is no substitute for experience. My advice is to take it out and use it! I have never used an MC-5 but I have used just about everything else. Proton mags don't really care which way they are towed, I usually follow the coastline or if in open water, a good way to decide is to figure out which way has the least magnetic drift.

3 to 4 knots is a good speed for that mag as Pete said. It should have either an altimeter to tell you how high off the bottom it is or a depth sensor to tell you how deep the fish is. When searching for Spanish Galleons, you need to run tight lines and keep the mag close to the bottom, but big steel ships are a little different. You can often see them from hundreds of feet away, so you may have better luck running 200 foot lanes and not worrying so much about the depth. When in 10 meters I would just float the mag under a buoy or PVC pipe.

My biggest tip: Lets say you run your survey in a north/south orientation, and you got one big hit like you would expect from a big steel ship. The center or peak of that hit will be the north coordinate of the object, but the east/west coordinate could be several hundred feet to the east or west. It is best to go back and run an east/west line over the target, and the peak of that hit will be your east west number. This will take you a little longer when surveying but will save you tons of time diving, because you won't have to search so much for your target.

You may find that your sonar is a better tool, especially in the mid-depths. They don't like shallow water, and they loose resolution as you go deeper but most steel shipwrecks are still sitting on top of the sand.

Good luck and keep us all posted on your efforts. I will try to get into setting up survey grids and importing them into your Garmin at a later date. That my friend is a looong story.

Jason

 

[ropesfish]

<I knew Jason would surface, so to speak >
Creeping around on manufacturer's websites is a good way to learn about things that you can seldom lay hands on casually like mags and high-end sidescans and sub-bottom profilers. Always look through their support/download/resources tabs and files too. You can find things like:
tow depth calculators for a towfish to get a ballpark idea of your starting parameters - Tow Depth Calculator - Geometrics

 

[Salvor6]

I only work in shallow water, 30' or less. So I let the whole 150' of cable out and use a fender bouy to keep the towfish just below the water.