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Need A SIMPLE Chartplotter - I don't fish
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Micahbigsur@msn.com



Joined: 27 May 2019
Posts: 484
City/Region: Big Sur
State or Province: CA
C-Dory Year: 2003
C-Dory Model: 25 Cruiser
Vessel Name: Sierra
Photos: Sierra
PostPosted: Sun Jul 14, 2019 11:11 am    Post subject: Reply with quote

I have installed shoot through the hull transducers, they do need to be placed over solid glass, but also in an area where the water flow against the hull is not turbulent. On our 25 the glass is solid only from the v-berth bulkhead forward which is not suitable on a planing boat. It seems to me that the usual mount on these boats is on the outside transom. Maybe the 22's are different?
Good luck.

_________________
Micah Curtis and Dana, RN
2003 C-dory 25 Sierra, 200, 9.9 and 2.5 Suzukis
2012 R25 SC Sequoia (2015-2018)
1978 Folkes 38 SV Audacious (2006-2015)
Micah, KJ6GUF, Dana, KJ6GXG
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thataway



Joined: 02 Nov 2003
Posts: 20778
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Sun Jul 14, 2019 12:01 pm    Post subject: Reply with quote

Most all of the C Dorys are laminated with either plywood, balsa or foam as a core. None of these will allow ultrasonic (depth sounder) frequency waves to pass thru the core material.

Some boats do have solid glass below the sumps for the bilge pump, others may have a lesser thickness of core material.

You can set a depth sounder transducer (for standard fish finders, not side scan) in a baggie of water, and move it around inside the boat to see if you can find an area where it will work. Very thick fiberglass (depending on the quality of lamination) may slightly attenuate the signal. But I shot thru over 1" thick solid glass in the Cal 46 and could hold the bottom at 600 feet with a low wattage depth sounder.

Inside mounts can be with silicone or a resin, such as epoxy (just assure that there are no bubbles). I often built a small box, of plywood, covered inside and out with fiberglass and a resin, laminated to the hull. I then fitted either a transom mount or thru hull most to the box, put a lid on, with a brass filler pipe and brass; we filled the box with mineral oil. This allowed easy change out of transducers when the electronics were up graded., Similar techniques were used in the racing boats to avoid any un-necessary protuberances below the surface of the hull.

_________________
Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL
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RobLL



Joined: 05 Aug 2014
Posts: 421
City/Region: Bremerton
State or Province: WA
C-Dory Year: 2007
C-Dory Model: 22 Cruiser
PostPosted: Sun Jul 14, 2019 12:21 pm    Post subject: Reply with quote

6 years ago I took the USCG auxiliary basic and navigation courses (both 3 months, once a week). The gal teaching thought the Lawrernce (mine) particularly poor, and was not all that impressed the the rest. She used a computer based system. She could take the computer home and plot hundreds of way-points etc. On her annual cruises to Alaska she could then choose the particular routes she would take that or the next day without any further programming. It did not take dozens of counter-intuitive pushes, hold, dances per 80s fancy watches to do anything.

The bitter end blog, now on facebook also raised the issue that computers, iPhones and pads may be, and would be, the better option. I dropped with unalloyed joy Garmins for my car. (thief got it - likely worth nothing, and I should have given her a hug)
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ssobol



Joined: 27 Oct 2012
Posts: 3358
City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
PostPosted: Sun Jul 14, 2019 12:32 pm    Post subject: Reply with quote

I used a stern saver mount for my transducer. Like this:

https://www.cabelas.com/product/STERN-SAVER-MINI-MOUNT/2421163.uts?productVariantId=4995791&WT.tsrc=PPC&WT.mc_id=GoogleProductAds&WT.z_mc_id1=04684214&rid=20&ds_rl=1246549&ds_rl=1246552&ds_rl=1252242&ds_rl=1252079&gclid=EAIaIQobChMI8I6T3-q04wIVgq_sCh0r8gbsEAQYAyABEgLD6_D_BwE&gclsrc=aw.ds
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Micahbigsur@msn.com



Joined: 27 May 2019
Posts: 484
City/Region: Big Sur
State or Province: CA
C-Dory Year: 2003
C-Dory Model: 25 Cruiser
Vessel Name: Sierra
Photos: Sierra
PostPosted: Sun Jul 14, 2019 3:47 pm    Post subject: Reply with quote

That looks like a good product to save your transom from screw holes
I also have used mineral oil in a glassed in pvc pipe to set a transducer in.
We use tablets for navigation as well as the chartplotter but a combo chartplotter with water temperature, depth, bottom profile, engine readouts, fuel flow, ais, and radar are so amazing along with your navigation suite it is magical compared to the old days.
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thataway



Joined: 02 Nov 2003
Posts: 20778
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Sun Jul 14, 2019 11:01 pm    Post subject: Reply with quote

For a number of years, I have been making my own Starboard blocks for transom mount transducers : 3/4" thick--using black Starboard recently, with black bottom paint. Initially I was using a small Dremel tool Dovetail bit to grove the back so the epoxy had a good bite. More recently, after some experimenting, I have gone to using a Fein (or other oscillating saw, with a 3/4" wide blade, and making cuts at 45* outward from a single "trench" in a series of grooves along the Back. Prepare the transom by sanding down to bare gel coat--use masking tape to define the area. Use G Flex Glue, do a rapid flame harden on the gluing surface of the Starboard. I usually use one of the old screw holes, pot it with epoxy, and put a screw to hold the Starboard in place while the G Flex dries. This is basically what these various kits do.

I am currently running two very large down/side scan transducers on the 8" x 4" block on the transom of the 25. You can move the transducers around to your hearts content, and no chance of damage to the transom core with multiple holes.
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