[PSUBS-MAILIST] Forward Facing Scanning Sonar

Sun Feb 25 15:06:51 EST 2018

Hank,
thanks, that's good to know. 
I like the Simrad Forward Scan but a bit expensive to put in the water &
hope it survives. It has a different style of transducer than a normal depth 
sounder, with a flat face. It does forward & down. 
I talked with Simrad experts at a boat show, then at their offices in Auckland.
 ( they do a lot of development work here. ) Also got them to email the transducer manufacturer in Europe. The conclusion was that they weren't confident it
would shoot through a hull without some distortion & as I said, didn't have a foggy 
about depth rating. They also had no bad ones I could cut in half :(
I like the idea of a shoot through hull depth sounder as although you would have
to make a small penetration for a fibreglass plug, you wouldn't have to seal around the
transducer, or feed the wiring through a penetrator. It would be easy to change
in the future. ( if you can unglue it).
If the simrad forward scan could shoot though fibreglass I would have it in the water but reinforce it with as little thickness of fibreglass as possible over the transmitting area.
Alan

Sent from my iPad

> On 26/02/2018, at 8:12 AM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Alan,
> I would not dismiss the possible depth rating of the transducer.  I just installed a new sounder in Gamma with 1,000 foot range and the transducer seems like it could handle all of that.  I had the original  one to almost 500 feet so far, so stay tuned and I will see how far we can push these things.
> Hank
> On Sunday, February 25, 2018, 11:33:47 AM MST, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Brian,
> thanks, that sounds promising. 
> I could temporarily glue a sheet of fibreglass on to the transmitting
> face of the transducer & try it out on a boat first.
> Alan
> 
> Sent from my iPad
> 
>> On 25/02/2018, at 7:21 PM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> Alan,   
>>            I have a depth sounder on my sailboat.  It's a low end Garmin, I made the decision to mount the transducer on the inside of the fiberglass hull, the fiberglass is quite thick in that area.  My boat is an Islander built in the mid 70's so they went overboard with the thickness of the fiberglass back then.  I get a very good image,  it even penetrates the mud !  I can tell because I checked the calibration at the dock and it was very accurate .  
>>  
>> Brian
>>  
>> 
>> --- personal_submersibles at psubs.org wrote:
>> 
>> From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>
>> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
>> Subject: Re: [PSUBS-MAILIST] Forward Facing Scanning Sonar
>> Date: Sun, 25 Feb 2018 17:22:07 +1300
>> 
>> Thanks Vance & Keith,
>> There seems to be quite a range of products out there & the ones
>> that have images that look like something recognisable are very expensive.
>>    The simrad forward scan is in my range but is 2d, so you are only seeing
>> contours & distances directly in front of you. I could enclose the transducer in a thick
>> shell of fiberglass with an area over the transmitting face that was only 3mm thick
>> & this would give me my depth rating, but it might be a waste of money if
>> it doesn't shoot through the 3mm well enough. Transducer costs $700 & 
>> display costs $1000.
>>    Could always put it on a boat if it can't shoot through the fibreglass, & there
>> is always the option of upgrading to a better scanner later on.
>> Alan
>> 
>> 
>> 
>> Sent from my iPad
>> 
>> On 25/02/2018, at 3:38 PM, via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> Scanning sonar is the set of eyes you don't have. It's invaluable for anything beyond just dawdling around having a look in the light pool. Unfortunately, 10-15k won't touch what Pisces carries. The acoustic altimeter alone is getting on for 5k. Ouch.
>> Vance
>> 
>> 
>> -----Original Message-----
>> From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>
>> To: personal_submersibles <personal_submersibles at psubs.org>
>> Sent: Sat, Feb 24, 2018 8:19 pm
>> Subject: [PSUBS-MAILIST] Forward Facing Scanning Sonar
>> 
>> Just wondering whether a forward facing scanning sonar is worth it.
>> I have been re-looking at them to see if there have been any recent
>> developments.
>> A couple that I have looked at that are for the rov market, are around
>> 10-15k. I looked at a video showing a camera image with the scanner
>> screen image in the corner of the screen, & it looked unintelligible.
>> Am wondering if just a depth sounder mounted horizontally would do
>> just from the low visibility collision avoidance perspective. I could make a
>> small fibreglass plug to fit in a small through hull & mount a "shoot through
>> hull" depth sounder inside my hull. Did a quick analysis & a 2" diameter 
>> fibreglass plug 1/2" thick fitted over a 1" diameter hole would give me a 
>> 15,000ft depth rating. Have talked with sonar people who have advised not 
>> to go more than 1/2" thick with the fibreglass I am shooting through & to 
>> leave no air gaps between the transducer & fibreglass. 
>> I did pursue the idea of adapting the cheaper Simrad Forward Scan for boats
>> but after getting little information from manufacturers & reps, dropped the
>> idea. They also said they didn't think it would work with a shoot through hull
>> & had no idea of it's depth rating.
>> Has anyone had any experience with forward scan or a forward mounted
>> depth sounder. Or from your submarine experience do you think this is
>> not really necessary.
>> Cheers Alan
>> 
>> 
>> Sent from my iPad
>> 
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