Changing Depth Finder -- New Hole instead of widening old hole?

[Mike or Sonya]

We are relatively new, so experienced advice is welcome. We purchased a 1996 300 Sundancer in Florida and had it brought home to Oklahoma where it stayed on the lake for a while until we had a trailer made in Florida and I went and hauled that home. Now the Sundancer travels regularly back and forth about 30 miles one way -- that is a key fact. We have purchased a Hawkeye depth finder to replace the Lowrance 3500 that was in the boat and only intermittently worked properly. We didn't even know where to find the transducer. We discovered it last night forward from the starboard engine and found that the transducer for the Lowrance is about a 1.25" hole which sits between the bunk of the trailer and the boat -- explaining why I (Sonya) could never find it when I crawled under the boat -- it was always sitting on it. The hole for the Hawkeye needs to be 2" as it is a P-19. Mike (Husband) Feels that traveling so much and sitting right on the trailer on it could not be good since the P-19 is not flush but has a slight raise to it. And since we would have to widen the hole any way -- we should just move to an area more towards center and make a new fresh hole.
I just wonder the effects of having another hole that close, and about what kind of sealant to use?
We will be delayed a bit due to the fact that I ordered a Transom mount and we evidently need a thru-hull so I will need to exchange..... oops.
Thank you all for your helpfulness. I have been pouring over posts for many months and I have learned much from you all.

 

[dtfeld]

Nothing wrong with just adding a second transducer. These need to go in front of all the underwater hardware. Maybe in front of the port engine? Access to it is always a consideration.

You could of course get the old one pulled and patch the hole, or enlarge it. 3M 5200 for sealing.

 

[Mike or Sonya]

Awesome! Thank you for helping!

 

[b_arrington]

For sealant, I would suggest something like 3m 4200. I would strongly advise NOT to use 5200. It is way too strong and not the right product for the application. If you ever had to remove the transducer, 4200 would let it be removed (with some difficulty) where 5200 would carry a very high likelihood of non removal and /or damage the the hull. It is seriously strong stuff.

 

[dtfeld]

5200 is for permanent installation for sure. 4200 cures faster, but has 1/2 the strength. Either will work.

5200 can be “unglued” with some products, but it’s a bitch. My local yard says heating will also release it....

For me anything permanent underwater needs 5200, but I’m paying someone else to do it because it is messy stuff, and if it leaks they can deal with it.

 

[Mike or Sonya]

Hmm. Ok. Definitely need to consider carefully my sealant then. Because at some point down the road I would like to upgrade to a fish/depth finder which has a display that shows the contours of the bottom of the lake and I don't know if the future upgrade in future years to come will use the same transducer.... You guys really rock!! Thank you for your honesty and reality with your answers!!

 

[b_arrington]

As a point of info, I installed a B60 transducer in my 270 AJ. Used 4200 and 12 years later had no issues. Suggest to do a bit of reading on best practices for the install. I can tell you that cutting the bottom with a hole saw is scary AF. Measure twice and drill once!

 

[ASH]

I would modify the trailer bunk to fit the existing hole. To make a small hull hole bigger you will need to use two hole saws stacked on each other. Another option is to figure out how the "fill" the small hole with something so the pilot drill bit will stay centered.

 

[Creekwood]

We are relatively new, so experienced advice is welcome. We purchased a 1996 300 Sundancer in Florida and had it brought home to Oklahoma where it stayed on the lake for a while until we had a trailer made in Florida and I went and hauled that home. Now the Sundancer travels regularly back and forth about 30 miles one way -- that is a key fact. We have purchased a Hawkeye depth finder to replace the Lowrance 3500 that was in the boat and only intermittently worked properly. We didn't even know where to find the transducer. We discovered it last night forward from the starboard engine and found that the transducer for the Lowrance is about a 1.25" hole which sits between the bunk of the trailer and the boat -- explaining why I (Sonya) could never find it when I crawled under the boat -- it was always sitting on it. The hole for the Hawkeye needs to be 2" as it is a P-19. Mike (Husband) Feels that traveling so much and sitting right on the trailer on it could not be good since the P-19 is not flush but has a slight raise to it. And since we would have to widen the hole any way -- we should just move to an area more towards center and make a new fresh hole.
I just wonder the effects of having another hole that close, and about what kind of sealant to use?
We will be delayed a bit due to the fact that I ordered a Transom mount and we evidently need a thru-hull so I will need to exchange..... oops.
Thank you all for your helpfulness. I have been pouring over posts for many months and I have learned much from you all.

When I replaced my 3500 plastic transducer I used the spot for a large bronze B60 for my Raymarine. Since I didn't care about the 3500, here is what I did to get it out and widen the hole.

I used a hole saw of the right size for the new transducer and started drilling dead center of the old one (from the bottom in case that isn't obvious.) When the pilot bit for the hole saw hit the inner ceramic element inside the transducer, I stopped and switched to a concrete bit of the same size as the hole saw pilot bit. The concrete bit will drill through the ceramic element. Once I was through, I switched back to the hole saw and drilled right over the transducer and the hull. So it drilled the new hole AND took out the old transducer in one step. Since Sea Ray located the 3500, I figured it was a good location for the new replacement.

But I guess if you want to move locations that won't work for you.
Edit: found a few pictures

 

[ColoSR]

Nextelbuddy is replacing his 3500 transducer similar to yours on the thread below. He might have some pointers if he is a little ahead of you. The P19 has a bronze equivalent, the B619, that might be an option if you would prefer to reuse the same hole. Just make sure that you get a model with the right deadrise. The thru hull P19 from Hawkeye is a 0 degree model, so you may need the 12 or 20 degree model depending on what your hull looks like.

The P19/B619 is really for basic depth/temp, if you are looking to do detailed sonar/fishfinder work you may want a different transducer.


http://www.clubsearay.com/index.php?threads/lowrance-3500-replacement-on-1997-searay-210.104615/

 

[Mike or Sonya]

When I replaced my 3500 plastic transducer I used the spot for a large bronze B60 for my Raymarine. Since I didn't care about the 3500, here is what I did to get it out and widen the hole.

I used a hole saw of the right size for the new transducer and started drilling dead center of the old one (from the bottom in case that isn't obvious.) When the pilot bit for the hole saw hit the inner ceramic element inside the transducer, I stopped and switched to a concrete bit of the same size as the hole saw pilot bit. The concrete bit will drill through the ceramic element. Once I was through, I switched back to the hole saw and drilled right over the transducer and the hull. So it drilled the new hole AND took out the old transducer in one step. Since Sea Ray located the 3500, I figured it was a good location for the new replacement.

But I guess if you want to move locations that won't work for you.
Edit: found a few pictures
View attachment 107528 View attachment 107529 View attachment 107530

The main reason for changing locations is that the current location is where the boat rests on the trailer --- weight bearing on the bunk of the trailer and the new transducer is not recessed but concave -- so that posed some concern.

 

[Mike or Sonya]

Nextelbuddy is replacing his 3500 transducer similar to yours on the thread below. He might have some pointers if he is a little ahead of you. The P19 has a bronze equivalent, the B619, that might be an option if you would prefer to reuse the same hole. Just make sure that you get a model with the right deadrise. The thru hull P19 from Hawkeye is a 0 degree model, so you may need the 12 or 20 degree model depending on what your hull looks like.

The P19/B619 is really for basic depth/temp, if you are looking to do detailed sonar/fishfinder work you may want a different transducer.


http://www.clubsearay.com/index.php?threads/lowrance-3500-replacement-on-1997-searay-210.104615/

Well, That does worry me. They did not ask me for any degree of slope at all when re-ordering. I (Sonya) do not know what angle or slope our bottom is. As to the last, however I know that it will be a few years before we are ready to go fishing or upgrade to a depth finder for fishing at all -- that will be on an entirely different lake.... But definitely good to know that information.
Thank you!

 

[Mike or Sonya]

Well, That does worry me. They did not ask me for any degree of slope at all when re-ordering. I (Sonya) do not know what angle or slope our bottom is. As to the last, however I know that it will be a few years before we are ready to go fishing or upgrade to a depth finder for fishing at all -- that will be on an entirely different lake.... But definitely good to know that information.
Thank you!

OH NO!! I went to their website and INDEED it does say on specifications 0-7 degree deadrise. Now a question while I cross my fingers ----- the small area that the transducer is going to be located in may not be as much of a slope as the rest of the boat --- does it go by overall degree or just the area it is placed in?

 

[Mike or Sonya]

Shifted boat over a hair so you can see original transducer right next to bunk. I have no idea what deadrise-- I just asked and they told me that it will only be off by a little should be ok to proceed. They have had people use with 20 degree and no issues---- maybe I can go with it?

 

[Little Ducky]

We will be delayed a bit due to the fact that I ordered a Transom mount and we evidently need a thru-hull so I will need to exchange..... oops.

Don't discount the transom mount.

If this is just temp until you get your fish finder I'd just go with the transom mount. Easy install and since you trailer you know exactly where to put it so it's not in the way. One small hole above the water line for the wires, some sealant in the hole and you are good to go.

 

[Mike or Sonya]

Don't discount the transom mount.

If this is just temp until you get your fish finder I'd just go with the transom mount. Easy install and since you trailer you know exactly where to put it so it's not in the way. One small hole above the water line for the wires, some sealant in the hole and you are good to go.

REALLY? We were told the transom mount would get nothing due to interference from v-drives?

UGH --- Its terrible being new and having such little knowledge ---Will be much better when we have experience and years under our belts!!!!

I just LEARNED there is an app called INstall Gemeco that is free that will let you use your phone or tablet to get your deadrise (also has wiring diagrams for airmar transducers and all kinds of neat testers)--- mine is 23 and 24 in the general area ---- so I am waiting Hawkeye's response as to what they think.
I had hopes of getting it all installed before the 4th but I keep making mistakes ----------learning steps.......

 

[KevinC]

As a point of info, I installed a B60 transducer in my 270 AJ. Used 4200 and 12 years later had no issues. Suggest to do a bit of reading on best practices for the install. I can tell you that cutting the bottom with a hole saw is scary AF. Measure twice and drill once!

+1 I agree with this 100% - transducers can fail and will then need to be replaced. Therefore they should not be considered permanent and 4200 would be the sealant of choice for this type of equipment.

-Kevin

 

[Creekwood]

REALLY? We were told the transom mount would get nothing due to interference from v-drives?

UGH --- Its terrible being new and having such little knowledge ---Will be much better when we have experience and years under our belts!!!!

I just LEARNED there is an app called INstall Gemeco that is free that will let you use your phone or tablet to get your deadrise (also has wiring diagrams for airmar transducers and all kinds of neat testers)--- mine is 23 and 24 in the general area ---- so I am waiting Hawkeye's response as to what they think.
I had hopes of getting it all installed before the 4th but I keep making mistakes ----------learning steps.......

You cannot use transom mount easily on vDrives unless you install it outside of the trim tabs and it won't work well. Your deadrise is in a specifications sheet or brochure. My guess is 21 degrees so a 20 degree is what you want. You don't want the hole on a strake. It should be on a flat spot between strakes with nothing on the hull ahead of it to interfere with water flow.

 

[Creekwood]

Do you have your manuals?:
https://s3.amazonaws.com/srweb-pvt-...ic/parts-manuals/1996__1996-300-SUNDANCER.pdf

Here is your spec sheet:
https://owners-resources.searayweb.com/model-archive-files/1C1_27_74DERNS8L864.pdf

 

[ColoSR]

I would be inclined to stay with the 20 degree dead rise version if you are drilling a hole. Airmar does make a 20 degree P19, you could just splice it into the Hawkeye

https://www.airmar.com/productdescription.html?id=140

If you are not worried about accuracy in deep water you could just glue the transom mount in the bilge and call it done. The signal goes through fiberglass hulls so no need to drill a hole if you don’t need temperature. Hawkeye has a video on gluing the IN-Hull/transom mount model in.