Max Boat Size for P79 Transducer?

scooper321

scooper321

Well-Known Member
Jul 4, 2015
1,857
Baltimore, MD
Boat Info
2003 Sea Ray 400DB
Engines
Twin Cummins 6CTA-8.3
I've got a 320DA. Earlier this year, I upgraded my plotter to a Simrad NSS9 evo2. Love it. Now looking to add the transducer. I don't want to add a hole to my boat and I don't fish. So I think the P79 will do me fine. But in their docs and ads, I see them say that it is for 25' boats max. Is that really true? What's the downside if I try to put it on my 32' boat? I can't really believe it won't work well. Any thoughts?

Thanks,
Steve
 
scooper321 said:
I've got a 320DA. Earlier this year, I upgraded my plotter to a Simrad NSS9 evo2. Love it. Now looking to add the transducer. I don't want to add a hole to my boat and I don't fish. So I think the P79 will do me fine. But in their docs and ads, I see them say that it is for 25' boats max. Is that really true? What's the downside if I try to put it on my 32' boat? I can't really believe it won't work well. Any thoughts?

Thanks,
Steve
Click to expand...

Its what I have installed on my 330. It works fine for my purpose. Holds bottom well and get decent fishfinder sonar. Location you install it is important. Original owner installed right on teh keel center line where the glass is about 3 inches thick. Worked like crap. I moved it to outboard of the starboard stringer as far forward in the bilge as it could be. Works fine now. Nothing ahead of it to cause interference in the water there and glass is thinner.
 
I have it as 2nd depth gauge on my boat and works fine under 10 kts... I guess faster than that there is too much turbulence in the area where I mounted it.
 
The Bill Collector said:
I have it as 2nd depth gauge on my boat and works fine under 10 kts... I guess faster than that there is too much turbulence in the area where I mounted it.
Click to expand...

Mine works right up to WOT and never losses bottom. If it ever does, it just means that the antifreeze fluid in the cup has evaporated and its time to top it up. I used to use mineral oil but I found it develops leaks in the 4200 sealant I use to mount the cup.
 
Last week I installed a P79 to work with a newly installed Simrad GO9, and it works great!
 
What does size have to do with it? It's hull thickness and materials that would affect it. I have one on my 340 with no problems at all..
 
The recommendation is merely a matching of the performance characteristics (wattage and beam angle) of the tranny to the boat size. For example the P79 is a 600w tranny so you are unlikey to run this on a larger boat with greater deepwater capabilities and on a head unit that will cater for a 1kw tranny. Conversely, you are unlikely to run a 1kw tranny on a 5 metre boat because of the narrower beam angle for the likely depth a 5 metre boat will be fishing in. - hence the recommendation for larger boat sizes for a 1 kw tranny.

Otherwise the P79 will perform fine on any boat size but will lose definition and or the bottom in deeper water.
 
Last edited:
mnm99 said:
What does size have to do with it? It's hull thickness and materials that would affect it. I have one on my 340 with no problems at all..
Click to expand...

Beats me. The main brochure for it (not the manual) says it's for boats up to 25'. I'm hearing that isn't really true...


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scooper321 said:
I've got a 320DA. Earlier this year, I upgraded my plotter to a Simrad NSS9 evo2. Love it. Now looking to add the transducer. I don't want to add a hole to my boat and I don't fish. So I think the P79 will do me fine. But in their docs and ads, I see them say that it is for 25' boats max. Is that really true? What's the downside if I try to put it on my 32' boat? I can't really believe it won't work well. Any thoughts?

Thanks,
Steve
Click to expand...

My requirements are similar to yours. I've got one on our 280 and no problems. I added it last year after the through hull died. I intended it to be temporary as a less expensive way to have depth data without hauling the boat mid season. I planned to replace during the winter but caught up with other events and the boat went in with the p79 still in service. It's still working fine. On your boat if you aren't fishing and aren't concerned that it only gets a response in depths less than 250' of water you be fine.


Henry


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Henry Boyd said:
My requirements are similar to yours. I've got one on our 280 and no problems. I added it last year after the through hull died. I intended it to be temporary as a less expensive way to have depth data without hauling the boat mid season. I planned to replace during the winter but caught up with other events and the boat went in with the p79 still in service. It's still working fine. On your boat if you aren't fishing and aren't concerned that it only gets a response in depths less than 250' of water you be fine.


Henry


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Click to expand...

I can't think of a spot in the Chesapeake Bay that's 250', so I should be ok. And no, no fishing on this boat.

I'm in the process of installing it now. Installed the base today, letting it cure overnight. I'll post pics when done.



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