Humminbird Side Imaging Forums
Side Imaging Forums => 898c SI => Topic started by: xiphias on June 03, 2012, 01:47:05 PM
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Hi all. Just received my 898c SI. This is going on a Jones Brothers Cape Fisherman 20. Question about whether I may need to go to a through-hull vs. transom mount.
The attached pics show the engine trimmed down to the lowest position I use in operation. I have 4-6" clear space from the transom to the lower unit. Looks a little tight, depending on the beam pattern.
The old ducer is a standard Airmar unit. Worked well in that position in terms of hull turbulence. There is a half-length strake under the hull a bit outboard of the ducer.
The blue mount is for a removable baitwell pump. It is outboard of the strake. It doesn't need to stay there.
Any comments on position viability would be greatly appreciated.
Thanks!
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Update. A more common and acceptable trim position provides about 6.5-7" clearance. Pic attached.
Thanks.
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xiphias
Some general thoughts on the location.
I think the area where the Airmar is will be to close to the outboard. SI is more sensitive to interference from the engine than 2D.
About 15" from the motor is recommended. Which will probably put you behind the 1/2 strake. The clearance from transom to motor looks good.
Can you temporally mount the TD to a board and C-clamp it to the transom? This would allow you to move left/right and up/down until a good
location is found without drilling extra holes.
My guess is that running a baitwell pump that close to the SI TD will create interference also.
Mike
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Thanks Mike.
You are probably right about the lateral position. At 15" it might be in line with the half-strake. But I'll check it out.
Good to know you think the distance from transom to lower unit is ok. That was/is my biggest initial concern.
I could try a temporary clamp mount, but two issues:
1) if this is definitely pushing it for the transom mount anyway, I do not want to assemble the transom mount and lose the ability to exchange with Humminbird for the through-hull.
2) a temporary mounting board is going to push the location aft by the thickness of the board. But I could do this with 1/2" ply (or maybe even 1/4"). If I'm already tight fore and aft, that 1/2" might make a difference.
Alternatively, I'm helping a colleague test his 798ci SI this weekend. We're doing a custom sidemount on a pole. I could pull his ducer off the sidemount and try that one on a temporary board. It's the smaller XNT-9-SI-180-T ducer, but might be a reasonable proxy.
The baitwell pump hasn't been used in years. Replaced with different method. So not a consideration from electrical or turbulence perspective. Good reminder to take it off though. Mostly just for spatial reference.
Thanks again.
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I have one of my transducers for the 798 mounted in a similar fashion. The left si is slightly less than the right.
I think using the 798 'ducer on a board will give you some valuable info, and help you make up your mind.
I also have a through-hull ducer, which gives me a better side image view.
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2nd photo of the same thing: