Topic: Humminbird 798ci Q? I'm new - Hello!

[sika]

Hello, I am from NZ and wanting to know a few things about this side imaging stuff. [This is a duplicate post, just found this forum]

I have read the FAQs. All good stuff in there.

I am looking at getting the 798ci HD SI Combo. I guess that is the one to go for.

I have a mounting question first. Below is a picture of my boat. I built it last year. It is a flat bottom dory. Flat, no deadrise at all.



It is flat bottom. Currently I am running a Garmin GPS/fishfinder combo. It uses a thru hull transducer.

Few Qs;
1. I see a thru hull transducer for the 798ci? I like the thru hull options because they dont get in the way. Shown here on the web XPTH Transducer BUT it says "798c SI Combo (does not include 800 kHz for high definition)"?
2. Will the 2" rubbing strip "keel" interfere with the SI transducer if I thru hull mount one?  Below is a pic of the hull (prior to finishing). The rubbing strips are 2" high.



The red circle indicates where I might have the thru hull. The current one is about here. I guess another question would be "what angle does the transducer beam come out at"? Will that angle allow the beam to miss the 2" rubbing strips? Make sense?

3. What are other mounting options? Does the outboard interfere with the si transducer. (refering to the pic of my boat).

4. Does this unit, combo work in saltwater. I googled that I man were there some arguments!

I am aware that only imperial versions come via the US. No biggie I guess, I can work in feet mph etc. Guess I will buy the Navionics charts also.

I have heard the GPS locating/startup times are aroun 5-10mins for US units outside the US? Is that true or horsesh#t?

Any other ideas welcome.
Regards.

[Humminbird_Greg]

1. Not sure what your question is here so I will guess that the “798c SI Combo (does not include 800 kHz for high definition)” statement left you with some questions. This transducer, like all HDSi transducers, was designed to produce both the 455kHz and the 800kHz Si sonar frequencies. The 798 units were designed to only use the 455kHz Si sonar frequency and cannot produce the 800kHz Si sonar frequency. All this means is that the 798 units will only have the 455kHz Si sonar capability – they will not also gain the 800kHz Si sonar capability just because they are connected to this transducer.

2. The fairing block that comes with the XPTH-9-HDSi-180-T transducer is only 1.6 inches thick, so I believe that the rubbing strips will interfere with the Si sonar.

3. Transom mounting is your only option as I see it. The Outboard can interfere with the Si sonar. The standard Compact Side Imaging (CSi) transducer that comes with the 798ci HD Si unit needs about 5 inches of clearance between the motor and transom so that it does not block any of the Si sonar. Many just trim up the motor while using the Si sonar since it is best used at low speeds anyways. If your boat does not have that clearance and you cannot trim up the motor you may have to look at installing a second CSi transducer on the opposite side of the motor and using an AS-Si-LR-Y cable to connect both transducers to the 798 unit.

A cold start for the GPS could possibly take that long but after that it should take less than a minute. We do not prevent the GPS from working just because it is outside the U.S.A.. Just a warning about using a domestic unit in NZ: the unit will not have the local Time Zone. Domestic units only have U.S. Time Zones. If you should need service for your unit you may find that the local service centers may refuse to offer service for your unit.

[sika]

Thanks for the reply greg. Will keep the thinking hat on.