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DST800 Adventure

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DST800 Adventure
07-23-16, 12:30 AM
Post: #1
DST800 Adventure
I thought I would write up what I call the great Tri-ducer Adventure. I wanted to document this whole (now successful) saga for other newbies. Many people are like me being in an area where popping down to the parts store or lots of support isn't possible. This is a bit long but I hope provides some thoughts and encouragement for the newbies (like me). I've always been grateful for the stories to help me be better; this is some small give back to the community.

I have a 1995 Beneteau Oceanis 321 currently docked here in Campbell River, British Columbia. Being on the north end of Vancouver Island, I don't have anybody who knows anything about my Raymarine set up. When I moved from Toronto, I had the boat trucked to and then had a complete retrofit done in Vancouver by the guys at First Yacht Services. Starting at the bow and rolling back to the stern, everything was done including replacing the original Autohelm instruments with:

a95 MFD
i70 Display
P70 Autopilot
iTC-5 Converter

I had that [censored] Navpod put it, bimini top added to the existing dodger, and so on. I'm the original owner and this was pure joy to get this done as I had always wanted to outfit her like the big shots in the 42 ft and up types!

Due to my being in Korea where I work, the guys brought the boat up from Vancouver to me on the Island. When I got home, stuff needed to be done as there were things not working. Thanks to Chuck on the Raymarine forum, most of the silly things that I was doing wrong (as in wrong screen = no wind speed shown) got corrected. One problem, tho, was the depth reading. Intermittent with nobody here in Campbell River (or anywhere up island) having a clue. The best I could get was disconnect the ITC 5, send it in to Raymarine. If it checks good, replace the DST800 Tri-ducer and off you go. Nobody on island or on the phone could offer much suggestions as there is very little else you can do.

So what I decided to do is run down a series of "lemmie just see" checklist items and see if there is the possibility there's something wrong with installation or wiring or some such before assuming the tri-ducer is bad or the ITC-5 is bad.

Here is what I did:

First, checked the wiring into the ITC-5. All good. Connected properly and the lights showed it good.

Next, wiggled the end, gently, on the tri-ducer insert to see if the indicator on the ITC-5 or the depth changed with the wiggle. I have an iPad with the remote view/control software so I could see all of this with my head in the bilge.

All was good but in a confirmed 15 feet of water while at dock, I was still reading 3 feet of water. Head out into 45 feet of water and depth was reading 5.5 feet of water and so on.

I then, while at dock, pulled the DST-800 insert and did two things. Cleaned it both the paddle wheel and the depth part of the insert. Upon putting it back, presto, we have 15 feet of water.

But only for 15 minutes. What I didn't realize at the time was that a cruise ship blew up the channel and created a big wake rolling into the marina. Bounced the [censored] out of the boats and back to 3 feet of water.

We took the boat out into the channel and, 10 minutes of good reading, then back to bad reading.

It was at this point, I went into my software training and started to think, okay, what's different. One thing at a time until I hit upon the through hull.

In 1995, the boat had two through hulls for instruments. On the port side was the paddle wheel for the Autohelm and on the starboard side, the transducer, also the original autohelm stuff. The "Tri-ducer" (all-n-one) didn't exist.

During the retrofit, the team used the port side through hull for the DST-800. This through hull was designed so you could pull that original paddle wheel unit out to clean off the wheel of whatever with a internal flap closing the through hull, limiting the amount of water coming into the boat. Always a good thing to minimize the water coming in via holes in a boat; so I'm told.

On the DST800, on the top, there is an arrow you use to point the device in the right direction; obviously to ensure the paddle wheel will work and give you speed indication. When lined up exactly forward, what was happening was that safety flap was pushing against the depth side of the insert underside and this resulted in the intermittent reading. Put the tri-ducer in backwards, perfect readings all the time but no speed obviously as the wheel would be in reverse.

To resolve this issue, I turned the insert just about 5 degrees off center to port. Just enough to essentially get the safety flap somewhat out of the way. We then zipped all over; zigging and zagging with perfect depth reading and the paddle wheel showing correct speed, SOG correct, essentially everything/every feature of my instrument set works perfectly now.

What all of this taught me was the notion of creating a checklist of parts and any differences between a/b in the case of upgrading/changing. To Raymarine's reliability credit, I always believed it was anything but bad equipment given things worked sortta, voltage was right, lights all showed good connections, etc.

So, there you have it. Hopefully, in the future a key word search will have this pop up and somebody will get an ah hah moment. Fair winds to all and if you're up in my neck of the woods, please look me up.

Fair Winds,

Rick Segal
S/V Tessie Marie
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DST800 Adventure - RickSegal - 07-23-16 12:30 AM

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