Finding the correct transducer location..and my fishfinder install

[ricohman]

This is probably the most important part of installing a fishfinder so any advice appreciated.
I have a Starcraft Islander 221 and a Humminbird 597ci HD DI.
Here is the transom.

I've read the manual and it suggests the right side. And that's a good thing as there are fittings on the left side.

The manual also suggests not mounting it right over the bunk and not to far outboard. So mounting it inside the bunk seems logical. But when you look at the bottom of the boat there is a small strake 5 feet forward. The manual suggests not mounting the transducer at the end of a strake but what about this situation?

On the other side of the bunk there is a strake that terminates at the transom, so thats no good. But there are a few inches which it could mount on the inboard side. And the Sternmate manual suggests the inboard side of a strake is better than the outboard side.

The inboard side of the bunk is only 16 or 17 inches from the centerline of the boat. I feel that may be to close to the leg?

If the boat is firmly on the trailer I cannot see how it could go forward enough to damage the transducer. Unless of course I miss the trailer at speed but then I will have much bigger problems anyway.
Do they caution this because the boat could come down and crush the transducer? With the Sternmate mount, it will be positioned back a couple more inches anyway.

 

[roscoe]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

I see nothing wrong with mounting directly over the bunk.
On one of my boats the transducer is mounted there, for the same reason as yours, except that my strakes all run to the transom.

Doesn't look like there is any way it could hit, unless you launch over the top of the trailer.

 

[ricohman]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

I see nothing wrong with mounting directly over the bunk.
On one of my boats the transducer is mounted there, for the same reason as yours, except that my strakes all run to the transom.

Doesn't look like there is any way it could hit, unless you launch over the top of the trailer.

I thought about this last night. If I position it between these two strakes it will be somewhat over the bunk. But beyond launching the boat over the trailer I cannot see any reason it would hit the bunk. But by then I would be running the boat into my truck.
Has anyone else ever used a Sternmate mount?
http://www.sternmate.com/Installation.html

 

[Bondo]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

I thought about this last night. If I position it between these two strakes it will be somewhat over the bunk. But beyond launching the boat over the trailer I cannot see any reason it would hit the bunk. But by then I would be running the boat into my truck.
Has anyone else ever used a Sternmate mount?
http://www.sternmate.com/Installation.html

Ayuh,.... I've got 2 fish finders on My Islander,...

The transducers are mounted 'bout 6 to 8" on either side of the drive...

'n they both work Perfectly...

 

[dingbat]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

If Bond-o didn't have one opeartional I would say good luck getting a transom mount to work with that rolled back edge and all the rivots on the bottom of the boat. Then again, I don't know Bond-o's criteria for perfect is

 

[1216bandit]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

You could always use some marine adhesive to secure some starboard to the transom then mount your transducer to that, no holes drilled into your boat, and easy to re-locate the transducer if you need too. I'd bet that if you scuffed up the starboard, 3m4200 would do the job. If you want to screw it into the transom, you may want to consider going close enough to the outdrive to allow for the possible addition of trim tabs down the road. I will be adding tabs to my Islander this year and have to move the transducer. Starboard is the same white hard plastic that a lot of cutting boards are made of. I got mine at a local industrial supply company.

 

[ricohman]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

I am using this.
http://www.sternmate.com/index.html
So the rolled edge and rivets won't be a problem. I'm not sure what starboard is but I don't think I will be needing it.
Thats great news about the transducer operation that close to the drive. That leaves more options for me. But it may start snowing again and the adhesive needs at least 65 degrees........I want warm weather.

 

[ricohman]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

This is where I think the tranducer belongs. This is the Sternmate transducer mount taped into position.
The Humminbird manual wants at least 15 inches from the prop blades. At this position the transducer will be about 17 1/4 from the edge of the prop.
Is this mounted to far outboard? It is in between two strakes. Once the Stermate is glued on, I dont want to have to move it.
Or am I thinking to much about this?
I won't be able to use the wood on the bottom to set my angle as the rivets at the transom protrude a bit, but I've read plenty about how to align it.

 

[ssobol]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

On my boat (a 16' RIB) the transom size limits the options for mounting the transducer. I could not get it as far away from the engine as the instructions said plus it is on the wrong side of the engine. However, the depth finder works without any problems. To check the operation, I was able to obtain a portable (detachable) mount. This consists of a suction cup and a mounting plate. It sticks on the back of the boat. I used it to test the operation of the depth finder before I drilled any holes.

The mount looks simple, but it held the transducer in place at speeds up to 30mph (my boat doesn't go faster than that).

It turns out that most of the depth finder transducers are manufactured by one company under OEM agreements (www.airmartechnology.com). I bought my holder from Blue Heron Marine. This holder was ~$30. But this is cheaper than mounting the transducer in the wrong place and having to fix it.

 

[CatTwentyTwo]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

I ended up moving mine closer to the center than the directions advised based on the suggestion of my electronics dealer. The transducer is 13 inches from the centerline so with my 15 inch prop it is only 7 or so inches from the edge of the prop. I have never felt anything that would make me think that the water flow to the prop was being disturbed even with it that close. I originally had it a couple of inches farther out but for some reason it would lose the bottom at anything above idle speed. Moving it just those few inches made all the difference in the world and now it will read the bottom up to about 25 mph.

 

[ricohman]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

I ended up moving it over a couple of inches. The Sternmate mount is glued on and although it was hard to take new paint off the hull the cement completely covers the bare aluminum so no worries about corrosion.
Now for mounting the control head. More holes! I got to get over this.
I am looking for the fuse panel and I don't think there is one. There is an access panel in the cuddy and I pulled that off to see the back of the instrument panel. Lots of room for the cables and a space above left exposed. I would guess it was left this way so you could mount stuff like this. Power it to the battery? Or to a switched source on the back of the panel?
One more thing. I have never had this boat in the water so I don't know where the water line will be. Can I assmue the top of the drive that is bolted to the transom will be exposed when the boat is floating?

 

[ricohman]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

This is taking longer than I thought it would....
Here is the final location and position. It may be a bit low but there is a lot of room to move it up or down if need be.

I pretty much set it how Humminbird wants it and with the sternmate mount it may have to move up a bit.

After drilling that 5/8 hole in the boat I didnt feel bad about drilling two more small ones. I filled the hole with 4200 after running the cable through. I also filled the screw holes with 4200. Do I need to run a bead around this fitting?

Now for wiring.
The back of the console has plenty of wires. I don't think this boat has a fuse block or panel so I am going to find a hot wire and ground. Then run my 3 amp fuse from that.

I am glad they left this spot open.

This will be the location of the control head. I moved it around and ended up with this location. To late to change it now.

 

[ricohman]

Re: Finding the correct transducer location

Re: Finding the correct transducer location

This may have just gotten a lot easier.
I found this fused hot with ground wrapped up inside the console. Its marked 25 amp and has a 1 amp fuse. Any reason I can't swap the 1 amp fuse for the three amp fuse and use it? I believe there are a few more like it in there.

 

[aharper00]

Re: Finding the correct transducer location..and my fishfinder install

I'm going to follow this thread as I'm looking to add a fish finder to my boat... glad to see the pics.

 

[dingbat]

Re: Finding the correct transducer location..and my fishfinder install

I have a hard time believing that the rivets and the rolled edge are not going to be an issue but......there is only one way to find out.

Lets us know how it works.

 

[Texasmark]

Re: Finding the correct transducer location..and my fishfinder install

Mount it inboard. I have explained this several times. Will not elaborate any more.

Mark

 

[ricohman]

Re: Finding the correct transducer location..and my fishfinder install

I have a hard time believing that the rivets and the rolled edge are not going to be an issue but......there is only one way to find out.

Lets us know how it works.

There are many decades worth of Islanders out there running transducers so there must be a way. This Sternmate is kind of like a jackplate for the transducer. I am very curious to see how it works and the final position of the transducer. I think it will end up higher and with the rear tilted up a bit.
First splash this week if the weather holds. The wind has been 60-70kmh lately.

 

[TerryMSU]

Re: Finding the correct transducer location..and my fishfinder install

I would recommend that you follow the instructions from HB if at all possible. For the answer to your second question, if I recall correctly, Humminbird specifically says to run wires directly to the starting battery (definately not the trolling battery) using a fuse near the battery.

The first question (placement) is a little more tricky, but it looks to me like you may be a little high in your mounting position. The reason to mount to starboard of the motor has to do with the direction of typical prop rotation. The bottom of the transducer is suposed to be just below the bottom edge of the boat (about 1/16 to 1/18 inch if I recall correctly.) Finally, you want to avoid any turbulence from the bottom rivets, strakes, etc.

I insalled my 597 on a welded tinny following the istructions a closely as posible, and it works as advertised (like a champ). BTW, I believe mine is closer to the motor than they would have liked, but my boat is quite narrow and I had strake issues as well.

I realize this is all a little late, but if you have issues try a PM to HB_DeborahCRC. She works for HB and I know she will have some wise input.

Good luck
TerryMSU

 

[ricohman]

Re: Finding the correct transducer location..and my fishfinder install

I would recommend that you follow the instructions from HB if at all possible. For the answer to your second question, if I recall correctly, Humminbird specifically says to run wires directly to the starting battery (definately not the trolling battery) using a fuse near the battery.

The first question (placement) is a little more tricky, but it looks to me like you may be a little high in your mounting position. The reason to mount to starboard of the motor has to do with the direction of typical prop rotation. The bottom of the transducer is suposed to be just below the bottom edge of the boat (about 1/16 to 1/18 inch if I recall correctly.) Finally, you want to avoid any turbulence from the bottom rivets, strakes, etc.

I insalled my 597 on a welded tinny following the istructions a closely as posible, and it works as advertised (like a champ). BTW, I believe mine is closer to the motor than they would have liked, but my boat is quite narrow and I had strake issues as well.

I realize this is all a little late, but if you have issues try a PM to HB_DeborahCRC. She works for HB and I know she will have some wise input.

Good luck
TerryMSU

I do hope it works. It will work at slow speeds as the water line is at least 12 inches above it but since I've never had the boat out I don't know where the hull sits on plane. But I have seen some pics of Islanders with transducers mounted in more or less the same position. The strakes really put it in this spot. Otherwise its right in front of the motor.
I went with the pre-wired connection. I think Starcraft provided this connection for a fishfinder as a lot of fishfinders (including some Humminbird) specify a 1 amp fuse. This 597 specifies a 3 amp so I just swapped the fuse. It powers up fine and according to my MM, has the same voltage as the battery. When I had a demo of the boat I believe the tech was pointing this feature out to me, but I forgot about it.
The instructions with the Stermate mount want the transducer a bit higher, into the rising water. This mount does move the transducer back from the transom, so it will need some adjusting. I think it will actually end up a bit higher, and with the tail end tilted up, not down as the HB instructions specify. Some of the pics I've seen of this mount have the transducer bottom level with the hull or slightly above. This is also supposed to eliminate a rooster tail.
All in all this is an experiment with new equipment on a new boat and if the wind would slow from the 70kmh speeds we have right now I would get it into the water and see how everything works.
If I had to move the tranducer, at least I have no holes in the hull!