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Old 12-08-2012, 16:55   #31
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Re: Locating Sunken Boat

I can chime in as another long time sidescan sonar operator. Started with the old double helix/revolving drum wet paper recorders, and the last one I used was the EG&G digital version. Also used Klein, Edo, Wesmar, Dowty, O.R.E. and GeoAcoustics systems. mostly 100 kHz, but also some of the 500 kHz systems, too. 40 years of finding and mapping and tracking stuff in the ocean. I was an employee of EG&G for 10 years, with O.R.E. 19 years, and did a lot of consulting as well. I've found lots of boats, cars, aircraft, anchors and military hardware. Lots of route survey work, pipeline inspection, too much to list it all.

Sidescan images can be really good if your wreck is a good reflector and is sitting in an area without a lot of other good reflectors. Just about any pile of debris on a smooth sand bottom will stick out like a sore thumb. But if the bottom is really rocky, it starts to get a little more difficult. If you're looking for a boat in an area of boulders, it starts getting hit or miss. Sidescans cannot tell you anything about the material, only their reflectivity. Things with air in them work really well as acoustic reflectors. Any time acoustic energy passes through the interface between two materials with different sound velocities, some of that energy is reflected.

Interpreting sidescan data can be difficult under some conditions. When it's easy, it's REAL easy, but when it's not it's frustrating.

It might be easier to start the survey with a towed magnetometer if you have the route mapped out. Almost any boat will have some significant ferrous material in it. Anchors, engine blocks, things that will give you a hit on a maggie. Then go back and either dive those locations, or rent an ROV and fly that down for a look.

If you're looking for someone who runs sidescans for a freelance living these days, Gary Kozak from Klein is still active and one of the best. I was just reading about him finding a submarine recently.
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Old 12-08-2012, 17:36   #32
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Re: Locating Sunken Boat

Theres an outfit in Lake Charles Louisiana, that makes bottom maps for the oil industry, and the Gov. I saw some of there work a few years ago that they did in Panama. They did a bottom scan of the lake bottom just to have something to do and to test there equipment !it was so good you could see the old railroad bed that was used to bild the canal !! it was as clear as anything you ever saw! and so many other objects that could be easily identfied !! Don't remember the company name but they could find anything ya want to find on the sea bed !! Im sure you could find them with a little web work !! don't know if this will help but we hope your search go's well !
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Old 12-08-2012, 20:56   #33
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Re: Locating Sunken Boat

Trimarans dont sink! even if you hole all three hulls they will float semi submerged on the surface until they are run down by a fish boat or cruise ship or more likely they will break up from the stresses of big seas with tons of water inside. They could also very likely be beat to little pieces on one of thousands of rocky shores in that part of the world. The chance of finding a trimaran shaped object on the bottom of someplace that is only guesswork is slim to none. I sympathise with the unexplained loss of a family member, but to even suggest that spending upwards of 100,000 dollars on a high tech wild goose chase is at best unfair to the family. This has hit emotionally far too close to home for me, and I think giving familys unrealistic hope is cruel.___Sorry folks, but that is my opinion._____Grant.
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Old 13-08-2012, 08:49   #34
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Re: Locating Sunken Boat

Gjordan, I agree with you on the search part. After running hunreds of them, I strongly suggest that if you don't have a search area narrowed down to a specific spot, you could waste a lot of time and money trying to find it, and might not know if it was there and you missed it. It's not conclusive unless you locate and identify. Sidescan's best used surveying the area around a spot where you already believe it is located. An eyewitness account, or a last GPS fix, that kind of thing. The shape of any debris, and the background it's sitting in, further complicates it. It's really hard to find things in the ocean if you don't pretty much already know where they are. 500 yards off might as well be 500 miles for most commercial sonars. You trade range for resolution with the frequencies.
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Old 26-08-2014, 10:50   #35
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Re: Locating Sunken Boat

Quote:
Originally Posted by LynnMarie View Post
My name is Lynn Hudak from Sumter SC....this morning in our paper The Item there is a unsolved death from 1976 of a male and a female that were killed in 1976 on Interstate 95 in Sumter County. They were buried as John and Jane Doe.

As of this morning there is a possibility that they are Michael McMinn and his wife Cordelia McMinn from OR.

Please notify Rob Cottingham rcottingham@theitem.com
(803) 774-1225
I follow Sumter "Mystery Couple" John & Jane Doe. IMO the McMinn's have been the best suggestion I've seen.

Sumter Sheriff John & Jane Doe 1976

Case File 189UFSC - Unidentified White Female

Case File 198UMSC - Unidentified White Male[/QUOTE]

Quote:
Originally Posted by subdude View Post
Drum, 25 foot trimaran, completed from a kit in Portland, OR in 1972
Owners: Michael and Cordelia McMinn. The two sailed to Hawaii and lived on various islands before departing in May of 1976 from Hanalei Bay, Kauai for Port Angeles, WA. Both were extremely skilled and resourceful sailors. They would both be 60 years old today.

The RCMP and FBI document four reputable sitings around the ETA (June) in the area of northwestern Vancouver Is and as far south as 25 miles north of Port Angeles in Canadian waters. Positive sitings are only of the boat and of one individual not matching the description of either owner.

Many other details exist which are not appropriate to post in this forum but which lend heavily to the theory of hi-jacking.

It was of course a long time ago, but as Michael's brother, I'm partial to keep searching for a lead. My aim in this and other forums is to perhaps jog the memory of the person(s) who might still be able to provide any missing pieces to the puzzle. Obviously, the window for this likelihood is swiftly closing.
Were you able to figure out how long it took to sail from Hawaii to where their boat was supposedly seen?

Thanks to you posting online; John McMinn and Cordelia McMinn were put in the National Missing and Unidentified System, NamUs; as of 2/14/13; both with a DNA profile to be compared to the Sumter "Mystery Couple"

What is very strange is that we have no clue if they've been compared to the "Mystery Couple"! Have you been told anything?
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