Transducer (39)Shoot Through Hull Installation on a 91 2655-gctid386590

[Guest]

I was reading the Lowrance installation manual for the transducer and it cautioned of epoxying it to the hull for "shoot through" if it's foam core/filled? Couple of questions for anyone with experience in this area.

1. Does my 91 2655 have foam between the fiberglass

2. Where is the best place to epoxy to the floor

3. Should I install it this way, because it also suggests external transom mount and I've read mixed reviews on Shoot Through accuracy?

Thanks

[dmcb]

I have 2 shoot thru the hulls on my 38xx and one expensive thru hull. The cheaper shoot the hulls are within 1 foot of the thru hull at over 100 feet.

Bayliner puts their shoot thru the hulls just ahead of the engine.

If your in the water, fill a baggy with water. Put it on the spot you want to use, place your transducer on it.

If it works you have a good spot.

I wouldn't want to put a screw in the transom where a leak could cause the wood to rot.

Doug

[2850Bounty]

Personally, I don't care for the idea. I'd prefer a true Thru Hull transducer!

But many BOC members, including Doug, have had good luck with this method.

love2speed wrote:
2. Where is the best place to epoxy to the floor

2... This will be against the hull within the engine bay.

Do as Doug suggests with the baggy of water placed tightly against the hull... no air pockets or voids.

.

[dmcb]

Trailering a boat with a thru hull fitting can be a problem also. If it doesn't line up properly, ouch.

With a shoot thru the hull you lose the temp part of the unit.

[2850Bounty]

dmcb wrote:
Trailering a boat with a thru hull fitting can be a problem also. If it doesn't line up properly, ouch.

With a shoot thru the hull you lose the temp part of the unit.

True!

I had to slightly rearrange my bunk location to accommodate my transducer. It was very easy to do.

[Guest]

Just installed an Airmar P79 shoot-thru on our 4087- works perfectly.

I don't believe the 2655 is cored.

[dmcb]

Pau Hana wrote:
Just installed an Airmar P79 shoot-thru on our 4087- works perfectly.

I don't believe the 2655 is cored.

Agree. I have put shoot thru transducers on 4 Bays now and all worked perfect.

Doug

[Guest]

It was an easy decision and install, Doug- the original Lowrance 3500 on the flybridge crapped out, and I just used the same spot the Lowrance transducer was epoxied at to mount the Airmar. Works great with the new Raymarine E7D

I just didn't want to haul the boat for this one reason, either....

[Guest]

Thanks for all the info guy's...so just to clarify, I fill a balloon/bag with water, put it in the engine bay where I'm plan on placing the transducer, then put the transducer on top of the balloon and check the reading on the unit. if I get the 6 inch reading (diameter of the filled balloon) I have a good spot? I guess another strategy is to get a depth measurement at my slip and gauge it's accuracy that way?

Also are transducers/unit wiring universal?? The PO had a Hummingbird Fish Finder (I know this because he left the mounting bracket and wiring intact). There is no transom mount transducer so it must be in the engine bay, I'll have to check that. Anyway I have a Lowrance, can I just tie into the existing wiring, it would save me a lot of hassle fishing new wires up to the cockpit.

Also I didn't realize you lose temperature with shoot through, no mention of that in the book, is this in all cases?

[Guest]

love2speed wrote:
Thanks for all the info guy's...so just to clarify, I fill a balloon/bag with water, put it in the engine bay where I'm plan on placing the transducer, then put the transducer on top of the balloon and check the reading on the unit. if I get the 6 inch reading (diameter of the filled balloon) I have a good spot? I guess another strategy is to get a depth measurement at my slip and gauge it's accuracy that way?

Also are transducers/unit wiring universal?? The PO had a Hummingbird Fish Finder (I know this because he left the mounting bracket and wiring intact). There is no transom mount transducer so it must be in the engine bay, I'll have to check that. Anyway I have a Lowrance, can I just tie into the existing wiring, it would save me a lot of hassle fishing new wires up to the cockpit.

Also I didn't realize you lose temperature with shoot through, no mention of that in the book, is this in all cases?

Basically, that is correct. Here's how I do it:

1) establish a baseline with the boat in the water: Make sure the power to the head unit is off. Tape the transducer to a pole, then dip the transducer into the water just below surface level. Turn the power on, and observe the depth reading/how the return looks. Be sure to write down the numerical depth reading. Turn the power off, and remover the transducer from the pole. N

2) Get a gallon sized ziploc bag- put the transducer in it, fill about 3/4 with water, and use a tiewrap to close. At your desired install location, gently place the bag into the surface, turn to the power, and observe the reading/how the return looks (if the numerical depth reading is a bit different that's fine). If the returns are almost identical, you have a good location to install. If not, find a new location and repeat.

The numerical depth reading may be different because you're installing the transducer below the waterline- your head unit should have provision to offset the depth reading to correct the difference.

Airmar makes most transducers. You'll have to find out if the Humminbird and Lowrance use compatible transducers, then call Airmar tech support. If they are compatible, then you can get the wirign diagram and pinout and go to town. Otherwise, you'll have to install the new 'ducer. As a rule, the newer generation of electronics are not compatible with the older transducers, especially if your Lowrance is an HDS unit.

You will lose temp with the shoot-thru. The question is, do you need a temp reading, or merely desire it?

[dmcb]

love2speed wrote:
Thanks for all the info guy's...so just to clarify, I fill a balloon/bag with water, put it in the engine bay where I'm plan on placing the transducer, then put the transducer on top of the balloon and check the reading on the unit. if I get the 6 inch reading (diameter of the filled balloon) I have a good spot? I guess another strategy is to get a depth measurement at my slip and gauge it's accuracy that way?

Also are transducers/unit wiring universal?? The PO had a Hummingbird Fish Finder (I know this because he left the mounting bracket and wiring intact). There is no transom mount transducer so it must be in the engine bay, I'll have to check that. Anyway I have a Lowrance, can I just tie into the existing wiring, it would save me a lot of hassle fishing new wires up to the cockpit.

Also I didn't realize you lose temperature with shoot through, no mention of that in the book, is this in all cases?

The bag against the hull WITH THE BOAT IN THE WATER, will tell you the hull at that point has no bubbles in the fiberglass and it isn't cored. That is if the reading is accurate. The 6 inch baloon reading would do what?

The idea is the signal goes through the baloon or baggy, through the fiberglass hull, and reaches the bottom. If there is an air bubble in the fiberglass or it is cored you will get a very distorted reading. Figerglass acts just about the same as water, per Humminbird.

The bag of water makes sure you do not have air between the puck and the hull. No bubbles in that either between the puck and the bottom.

All transducers are not the same. If the same frequency it will work with another unit. If it isn't, it won't.

The puck now installed most likely will be just ahead of the engine.

If you operate two sounders at the same time that use different frequencies, both will work properly.

If both are the same, they will not.

You will not lose temp but you will get an accurate reading. It must be in the water for that.

Doug

[Guest]

I did not epoxy the mounting flange on mine, I used silicone glue. It can be easily removed later, however mine is perfect where its at and held on for 3 seasons now.

[Guest]

I used GE silicone, and filled the reservoir with RV antifreeze.

[Iproff]

I mounted the transducer for my Lowrance in the bilge are of my aft cabin. I used the same method that Doug described to test the location. The chartplotter has never failed to keep the bottom of the lake even at 35 mph. The accuracy for identifying fish is diminished but its the depth of water I am concerned with and want the transducer as far forward as possible and still reading while on plan.

Ken

I used a 5 minute epoxy that comes in a double syringe to secure it to the hull.

[Guest]

Thanks for the tips everyone, i will report back, specially on whether or not I can tie into the existing Hummingbird harness.

just a quick question for Pau Hana what do you mean "I used GE silicone, and filled the reservoir with RV antifreeze" what reservoir?