Humminbird Scupper Hole Transducer - Improving Drainage

The Humminbird scupper hole transducer greatly reduces scupper drainage. If you have a Trident, this slow drainage can result in water leaking through the rod pod. This was discussed in Rhyak's Catalina sinking and I had it happen to me in a recent surf adventure resulting in several gallons of water in my hull. To improve drainage, I cut the end off a 1" pipe fitting the cut it in half and drilled it out. This was epoxied into the scupper hole to create a 1/2" gap. I Marine gooped a small piece of 1/2" pipe to the back of the transducer to create a 1/2" gap. Tightened up the nut and it drains great.

how does the water get in to the rod pod due to this? Is it cuz it fills the area to far upwards and it overflows into the rod pod or by some other path?

nice hack scott.

MikeinFresno..when a surf launch goes wrong and you take one over the bow, the entire cockpit can become flooded.  Water can seep into the rod pod at the lowest spot, which is between your legs near the seat.  The longer it takes to drain, the more water that can get it.

Ok, so the lid isnt a good seal and the yak is swamped, I see

Nice fix Scott.Hold on to some PVC stock for me if you have extra please.
Thanks,
Aaron

Nice fix Scott.Hold on to some PVC stock for me if you have extra please.
Thanks,
Aaron

Aaron -

I fabricated some fittings for you and will give you them on Saturday.

Scott

Scott, I understand the purpose of the drilled-out spacer, but what is the purpose of the piece you epoxied to the transducer? Is it to create more gap space too?

thats the way I see it, lets the water out quicker due to the gap created

In the standard installation there are 2 reasons for poor drainage:

1. The nut on top blocks the top of the scupper hole with only small gaps.

2. The bottom of the scupper hole is blocked because the transducer is pulled flush against the hull.

Over time, mud and sand leak into the scupper hole around the nut and accumulate on top of the transduer reducing drainage even more. If you look carefully at the picture of the transducer you can see the mud and sand stuck to the stem above the transducer. I would say that 2/3 of the drainage problem can be fixed by creating the lower gap above the transducer which is what Rhyak did, I believe. I wanted max drainage because I surf launch alot and when you punch through big waves, the cockpit floods so I created the upper gap. I also put a dab of marine goop on the front of the transducer and on the PVC spacer so the transducer is attached to the hull at 2 points. I believe you could use marine goop to attach the upper spacer also.

Thanks for sharing this Scott...I hav a humminbird with the scupper hole transducer that I am trying to install (hoping it magically jumps out of the box and installs itself actually!!  ).

Just one question...when you have the spacer on the bottom (which makes total sense to me now) do you think the transducer will stick out far enough below to potentially get caught on kelp or damaged in landings etc...

I have never used a FF before so please forgive me if the question is silly.

Thanks again.

Sincerely,

Jim

Thanks for sharing this Scott...I hav a humminbird with the scupper hole transducer that I am trying to install (hoping it magically jumps out of the box and installs itself actually!!  ).

Just one question...when you have the spacer on the bottom (which makes total sense to me now) do you think the transducer will stick out far enough below to potentially get caught on kelp or damaged in landings etc...

I have never used a FF before so please forgive me if the question is silly.

Thanks again.

Sincerely,

Jim

Jim -

I used a 3/8" spacer but you could use as small as 1/4". The aft section of the the transducer does stick out a little more so is slightly more vulnerable if you are dragging your yak over rocks but does not get hung up in kelp or increase drag. For the type of fishing you do, I don't think there is a downside. I will cut you some fittings for you and give it to one of the A Hulls. I have a ton of PVC. BTW, the Humminbird scupper hole installation is as easy as they come but the design was poorly thought out where the Trident is concerned. Too many Tridents have taken on water, IMO. I am going to have to hook up with you and Porky before the end of the season.

Scott

Thank you Scott for the reply, picture and offer of the PVC...I would be stoked to get some from you!!

Just let me know when you want to go fishing and we will make it happen!!
 
Sincerely,

Jim

Hi Scott,
I just bought the 385ci combo kayak for my T-13, and it should be here in a couple of days. Would you recommend the scupper transducer?, or mount the standard transducer(comes with easy mounting kit) inside the hull? Do you think there are any differences in performance?
Jim

Hi Scott,
I just bought the 385ci combo kayak for my T-13, and it should be here in a couple of days. Would you recommend the scupper transducer?, or mount the standard transducer(comes with easy mounting kit) inside the hull? Do you think there are any differences in performance?
Jim

Jim -

Personally I like the scupper hole installation vs shoot through hull but both have their pros and cons. Note that you will have to exchange the transducer that comes with the FF for the scupper hole version and as I remember, there was a cost to that. Here are the pros and cons:

Shoot Through - No additional cost, transducer more protected, no additional drag.
Scupper Hole - Better signal (depth and resolution), accurate water teperature, more reliable.

I used shoot through transducers for several years but got frustrated because they pop loose eventually and the signal is not as good. Because I fish trout, accurate water temp is also good.

Scott

Thanks Scott,
I'll go with the scupper type and use your mod. for better drainage. Dang, now I'm going to have to wait another 1-2 weeks for the trans. swap to use my new toy.
Jim