Through-Hull Transducer

[fritz3000g]

Hi there,

I went aground in a shallow mucky lake (Lake Winnebago) this weekend on my '84 Mac25 , and realized I probably eventually need to replace my depth finder indicator (the old one is busted).

It has an existing through-hull transducer epoxied to the hull, and I'm wondering if through-hull transducers tend to work on Mac25s or not?

Interestingly, I slept on the boat outside a small marina in Oshkosh, and walked around the boats stored on land. Turns out 5 of 7 were MacGregors (all 25s or 22s I think). I guess it's a popular boat for Lake Winnebago!

[Sumner]

If you are asking about having the transducer inside the boat shooting through the hull most depth finders will work that way. The one that came with our boat was installed like that.



I added another one with some GPS ability and ....



.... mounted the transducer for it on the stern as I wanted water temperature...

http://purplesagetradingpost.com/sumner ... 20350.html

Sumner

============================
1300 miles to the Bahamas and back -- 2015

The MacGregor 26-S

The Endeavour 37

Trips to Utah, Wyoming, Idaho, Canada, Florida

Mac-Venture Links

[BOAT]

Hi there,

I went aground in a shallow mucky lake (Lake Winnebago) this weekend on my '84 Mac25 , and realized I probably eventually need to replace my depth finder indicator (the old one is busted).

It has an existing through-hull transducer epoxied to the hull, and I'm wondering if through-hull transducers tend to work on Mac25s or not?

Interestingly, I slept on the boat outside a small marina in Oshkosh, and walked around the boats stored on land. Turns out 5 of 7 were MacGregors (all 25s or 22s I think). I guess it's a popular boat for Lake Winnebago!

I don't know of any water ballast boats with a "THROUGH HULL" transducer, nor would I suggest anyone try to install one.

If you mean the IN-HULL transducers . . .

They work quite well.

I have this one:



These things are sold direct from Garmin and RayMarine - but they both use the exact same sensor - it's actually made by Airmar. Airmar makes really good stuff. I sure would like an Airmar wind instrument on the mast.

There is a place in the M boat where this can be mounted and is not over the ballast tank (you can't mount these over a ballast tank). I assume this will work on the X too - but not sure about the 25 - Apparently sumner knows of a place in the 25 to mount one that is not over the ballast tank?

[FLGSHP7]

In my 26s it's mounted through the hull in the lazarette floor.

[Russ]

What I've done is cut the bottom out of a plastic bowl and lay it where I want the transducer. Then squirt a tube of clear silicone caulk to make a "bed" being careful not to introduce bubbles. Then smash the transducer into the bed and let it dry. Easy peezy no holes. Cut it out with a knife if you want to remove it.





If the boat is in the water, you could place the transducer in a baggie full of water and set it down inside the hull to see if it gets a bounce to test before mounting it. cavity.

[BOAT]

Just make sure when you do the test that the ballast tank is empty.

[Seapup]

I went aground in a shallow mucky lake

Soft is good for grounding at least muck bottoms are sometimes tough to get a signal off of when you are shallow enough to hit bottom anyway.

Just make sure when you do the test that the ballast tank is empty.

I was surprised how easily you can just slap a transom mount transducer in a boat as long as its touching the actual hull bottom. I scraped barnacles off my transom mount for a few years before I realized the same transducer can be mounted inside and still have a fairly accurate temperature too.

Easiest I found is a thin smear of toilet wax inside the hull and stick the transducer in it somewhere out of the way. No waiting and easy to move later.

Toilet wax is part of my spares kit, it will plug a through hull or stop a leak amazingly well. Very similar to:

[fritz3000g]

Thanks guys! I'll see if I can reuse the existing transducer then!

With the Mac25, there was no water ballast - it's a cast iron swing keel.

[Russ]

I scraped barnacles off my transom mount for a few years before I realized the same transducer can be mounted inside and still have a fairly accurate temperature too.

Interesting. I may try installing another inside like this and if it works well get rid of the transom mounted one that makes me nervous that it could break off (leaving holes where the screws pulled out).

[reastmure]

Hi there,

I went aground in a shallow mucky lake (Lake Winnebago) this weekend on my '84 Mac25 , and realized I probably eventually need to replace my depth finder indicator (the old one is busted).

It has an existing through-hull transducer epoxied to the hull, and I'm wondering if through-hull transducers tend to work on Mac25s or not?

Interestingly, I slept on the boat outside a small marina in Oshkosh, and walked around the boats stored on land. Turns out 5 of 7 were MacGregors (all 25s or 22s I think). I guess it's a popular boat for Lake Winnebago!

I don't know of any water ballast boats with a "THROUGH HULL" transducer, nor would I suggest anyone try to install one.

If you mean the IN-HULL transducers . . .

They work quite well.

I have this one:



These things are sold direct from Garmin and RayMarine - but they both use the exact same sensor - it's actually made by Airmar. Airmar makes really good stuff. I sure would like an Airmar wind instrument on the mast.

There is a place in the M boat where this can be mounted and is not over the ballast tank (you can't mount these over a ballast tank). I assume this will work on the X too - but not sure about the 25 - Apparently sumner knows of a place in the 25 to mount one that is not over the ballast tank?

I thought you could mount these over the balast tank and will work as long as the balast tank is full? Where on the M do you mount where there is no balast tank?

[BOAT]

reastmure wrote:
I thought you could mount these over the balast tank and will work as long as the balast tank is full? Where on the M do you mount where there is no balast tank?

Nope. No can mount on ballast tank -
even if the tank is full you will get line across sonar screen says something 12 inches below your boat - it will still "see" the hull under the ballast tank and image it as a target (but what it is really is just an echo bouncing off the bottom of the boat) On the larger power boats they call it "Ring Down" - The line is usually not a big problem when shooting deep depths but can make the actual sounding inaccurate on the depth numbers at the most critical times: (when you are in shallow water). It just depends on what your expecting from your sonar. If your looking for fish - the bubbles in the tank will make ghost readings - if your not looking for fish who cares? right? If you trying to run super shallow waters you will always be fighting two images of the bottom - one the real image and the other the 'ring down' created by your ballast tank.

For me, the main thing is seeing shoaling: We have a real winter shoaling problem here in my home port so if i am sailing into the harbor I need to see the big moguls of sand that have piled up under water out in front of me so I can maneuver around them. Then my wife is always bugging me to find animals for her to take pictures of, so I also want to use the sonar to find the whales and dolphins so my wife can take their pictures when they come up to breath the air. So for me I decided to go with this sensor and mounted it under the dinette:



It works real good and I even made a stupid movie of the sonar in action - (I made it really silly because my daughter likes to be entertained by the silly movies I make):

https://vimeo.com/176998271

Sorry the video is so silly, but at least you can see what the sonar image looks like.

[ULLR]

My m 22 had a basic fish finder for a depth sounder. PO epoxied a piece of 4"pvc, filled it with some sort of oil and dropped the transducer inside it. It was then covered with a plastic cap w/ a hole drilled through it for the wire to pass through. Worked great as there was no water ballast in the boat so it was basically mounted right to the hull and didn't involve drilling any holes through the hull. I actually liked it as you could nose into places to check depth without exposing prop to hazards. My M is mounted on starboard side of transom and works well also but did prefer having it in the bow.

[BOAT]

I get a circle of coverage under the boat but the sounder projects the soundings as a flat 2 dimensional image. Whatever the shallowest sounding is that it gets in that circle of coverage is what it projects on the screen, so a sand mogul eight feet high showing on the sonar might actually be slightly to starboard from you, (or to port). So you need to do a little creative maneuvering to sonar your way around the moguls by turning the boat to change the image - that's how you maneuver around them. In the winter the moguls move around all winter long so making a note of where they are is pointless, (they keep moving!! )

Usually the sand moguls here sit on a 15 foot bottom and will pop shallow to about 4 to 8 feet so you can't see them but they can touch your DB. Add to that some huge swells and it gets a little dicey. The keel boat skippers here are experts at sounding the shoals. My first winter at Oceanside Harbor I clipped the moguls twice in big swells entering the mouth of the harbor. It made chips in the dagger board, (I had to fix them .)

Winter shoaling is noted on all the good electronic charts here:



You get used to them after a while - in the summer time the big dredge comes in and sucks out all the sand moguls and puts them on the beach for the kids to play on.

[Tomfoolery]

* Pop Quiz *

Who knows what the day shapes on that barge mean? No peeking.

Bonus question: What colors are associated with the two shapes shown when operating at night?

[BOAT]

* Pop Quiz *

Who knows what the day shapes on that barge mean? No peeking.

Bonus question: What colors are associated with the two shapes shown when operating at night?

This is a great time for you guys to really show us how smart your are - I'll go first and say that I do not know what the circle over diamonds mean - all I know is that something in that mess of symbols has something to do with a towed structure or barge or slow moving "thing" or some kind of signal to other boats. I will not cheat and admit right up front I don't know.

Who's next? (I'm betting my money on Catigale for this one).