Somewhat to Josh’s point, I mentioned in the spring I would report back on my 
experience on the DX900+ and ForwardScan.

While I cannot comment on the ultrasonic as far as speed goes, the Airmar techs 
kind of were suggesting that (UDST800) over the DX900, which gave me pause, 
(like maybe they didn’t think the DX900 was ready for prime time)  but I am 
drawn to new tech stuff, so I went with the electromagnetic.

In poking around areas I am familiar with, it seemed to me that electromagnetic 
was not fooled by heavy weeds or light mud. I could remember my last Raymarine 
bouncing around while going through those same weedy areas, but this did not. 
The speed is ultra sensitive & very accurate, I had to dampen it somewhat. I 
never thought to check it in reverse to see if it indeed would register a  
negative – reading, unfortunately. Have not messed with the leeway function, as 
this currently must be done on a Tabled with Bluetooth, and I still haven’t 
gotten my boat pointing in the appropriate direction, so first things first. 
This certainly would not work mounted on the inside of the hull.

 

When the boat was just hauled, it was clean as a whistle. I put water-base 
antifouling on it, (but not the 5 sensors). The forwardscan was also clean as a 
whistle, also with water based antifouling. I am in fresh water, so there is 
that, but I think the fact that the forwardscan transducer sticks out around ¾” 
keeps it a little cleaner.  They recommend cleaning them every few weeks, but I 
never touched them.

It is very handy when coming into unknown marinas and shallows, I think I will 
use this much more when I have a MFD that can show it in the cockpit. I did use 
tablet to view on occasion, but would be easier with a dedicated display. When 
left on Auto calibrate, the forward look is much further out vs. in shallow 
water.  I think the ForwardScan drew me in, because I remember 20 years ago 
forward looking sonar was around 10 grand, as compared to $600 now.

 

Bill Coleman

Erie PA

 

From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Josh Muckley 
via CnC-List
Sent: Wednesday, October 30, 2019 9:23 AM
To: C&C List
Cc: Josh Muckley
Subject: Re: Stus-List Advice on replacing 33-2 BandG 32mm transducer with 
Airmar 52mm transducer

 

As I understand it, that location forward of the keel was expected by the 
designers to be the location for the speed and depth transducers.  As such the 
hull is solid in that location.  

 

If you drill it out and find otherwise then a typical removing of the core 
while leaving the inner and outer skins in place would be appropriate.  Dig the 
core back as far as possible.  With a 52mm hole, angling a drill bit and other 
various implements should be pretty easy.  Back fill the cavity with thickened 
epoxy, allow to cure, and redrill the 52mm hole as needed.  Install the 
transducer with 5200.

 

You will most likely find that the original was bedded with 5200 and will not 
come free.  There are products available that are supposed to loosen/weaken 
5200.  Try them first but it may still take days of soaking.  If that fails 
then a sanding drum on a drill can make pretty short work of the plastic and 
5200.  For the new hole, a hole saw typically needs the drill bit to center and 
stabilize the drum but with a 32mm hole already there it can be difficult.  
Create a stabilizing core by getting a hole saw that fits the existing hole 
(either in the hull or in the existing transducer fitting) and drill a plug 
from a 2x4.  Now change the saw to your 52mm and slide the wood plug over the 
drill bit.  The plug will act as a centering guide as you drill the new hole.  
Depending on the size of the old fittings this may be sufficient and 
pre-removal may be unnecessary.

 

I find biological growth to fowl my speedwheel constantly during the summer 
months.  I'm frequently removing the speedwheel with the boat in the water 
resulting in a small geyser.  To avoid this I am seriously considering an 
ultrasonic speed sensor.  Have you considered this yourself?  I would like even 
more if I could find one that was able to be glued to the inner hull and simply 
shoot through.  I know some depth transducers are made this way but speed is a 
different story.

 

Josh Muckley 

S/V Sea Hawk 

1989 C&C 37+

Solomons, MD

 

 

On Wed, Oct 30, 2019, 8:55 AM Doug Welch via CnC-List <cnc-list@cnc-list.com> 
wrote:

It's time to replace the B and G Network Quad instruments on my 33-2. This 
means replacing the old 32 mm paddle wheel speed transducer with a 52 mm airmar 
transducer. I understand that the 33-2 is partially cored hull, so my question 
is the area where the transducers are currently located cored. They are located 
in the locker at the foot of the vberth. Any other advice on removing the old 
and installing the new is gratefully received. I went with a Garmin Echomap 
plus cv75 and sonar,depth, temperature transducer.

 

Cheers,

Doug Welch

Celtic Knot 

33-2 c/b 

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