I recently purchased my first Parker and so far I’m loving it! I live in San Diego and use it for West Coast style fishing. One thing I will have to do is update all electronics since the ones currently on it are from 2004/2005. One of the components will be a new thru hull transducer (Airmar); however it currently has an Airmar B744V which is mounted with a fairing block. I’m thinking of getting a B175HW but my question is, can this be installed in same location as the old one? I know it is shaped differently and would I need to get a different fairing block? Or no fairing block? Will I need to patch up part of the existing hole, to accommodate the new transducer? Attached are pictures and dimensions of current transducer and fairing block…thanks in advance for your help.
Updating Electronics on 2005 2120, need help with replacing transducer.
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warthog5
Well-known member
Your in luck.....The small Bolt hole, that stops the assy from spinning will need to be filled. The main hole in the hull [stem of X-ducer] is 2in.
That will be temparily filled.... Your going to re drill in that spot.....A 3 3/4in hole.
That old B744V is a 600watt unit, non CHIRP. The B175HW is a 1000watt and it's Chirp.. It is a Tilted element unit.... There is NO fairing block.
On the B744V it has a Arrow on it......Arrow points FRONT.
On B175HW it has a arrow also.....It points at KEEL..... Do not make a mistake and point it FRONT like I have seen in the past. It even says KEEL with arrow beside it on top of unit. I just shake my head and say......"Failure to follow Instructions!"
Now....The B175HW is designed for shallower water...... What kind of depth is your normal fishing?
The #1 unit I've installed a bunch of around here is the B175M.
https://www.airmar.com/productdescription.html?id=147
That will be temparily filled.... Your going to re drill in that spot.....A 3 3/4in hole.
That old B744V is a 600watt unit, non CHIRP. The B175HW is a 1000watt and it's Chirp.. It is a Tilted element unit.... There is NO fairing block.
On the B744V it has a Arrow on it......Arrow points FRONT.
On B175HW it has a arrow also.....It points at KEEL..... Do not make a mistake and point it FRONT like I have seen in the past. It even says KEEL with arrow beside it on top of unit. I just shake my head and say......"Failure to follow Instructions!"
Now....The B175HW is designed for shallower water...... What kind of depth is your normal fishing?
The #1 unit I've installed a bunch of around here is the B175M.
https://www.airmar.com/productdescription.html?id=147
A couple things in addition to what Warthog said, which is correct:
You’ll have to special order the 3-3/4” hole saw. Don’t expect to find one in your local box store. I would definitely recommend getting one, however, as opposed to doing it with a rotozip or similar tool- much cleaner hole.
As an alternative to temp filling and redrilling the hole, if the existing hole is cleanly cut with a hole saw you can buy an arbor that allows you to use the hole saw that is the appropriate size for the existing hole as the guide, while the bigger saw on the outside cuts the larger hole. This will work as long as you want the new transducer centered in the same spot as the old one. If you want to move it you’ll need to go the route Warthog described.
Example here:
You’ll also need to cut away more of the shelf that’s over the existing transducer- the B175 has a much bigger footprint on the inside of the hull. Depending on clearance, you may be able to use a jigsaw for that, but an oscillating multitool may be easier if it’s a tight spot in the bilge.
As far as the HW model goes, if you’re trolling for pelagics high in the water column beneath you, it’s the bees knees. Gives you a nice wide view of what’s swimming around beneath the boat. If you need pinpoint accuracy of bottom structure much below about 100’, the transducer will show it, but the cone is so wide that whatever structure it’s seeing could be 20’ or more on either side of the boat. A frequent installation we see here in the northeast is a HW for trolling in conjunction with another model (H, M, or L) depending on the exact type of bottom fishing the owner prefers.
Here’s a good transducer reference from Airmar:
https://www.airmar.com/uploads/brochures/tilted-element-chirp.pdf
Personally I love my HW. Upgraded from a B60, incredible difference. I’m planning on adding a StructureScan 3D module, so that should carry most of the bottom fishing load in the depths that I frequent.
You’ll have to special order the 3-3/4” hole saw. Don’t expect to find one in your local box store. I would definitely recommend getting one, however, as opposed to doing it with a rotozip or similar tool- much cleaner hole.
As an alternative to temp filling and redrilling the hole, if the existing hole is cleanly cut with a hole saw you can buy an arbor that allows you to use the hole saw that is the appropriate size for the existing hole as the guide, while the bigger saw on the outside cuts the larger hole. This will work as long as you want the new transducer centered in the same spot as the old one. If you want to move it you’ll need to go the route Warthog described.
Example here:
You’ll also need to cut away more of the shelf that’s over the existing transducer- the B175 has a much bigger footprint on the inside of the hull. Depending on clearance, you may be able to use a jigsaw for that, but an oscillating multitool may be easier if it’s a tight spot in the bilge.
As far as the HW model goes, if you’re trolling for pelagics high in the water column beneath you, it’s the bees knees. Gives you a nice wide view of what’s swimming around beneath the boat. If you need pinpoint accuracy of bottom structure much below about 100’, the transducer will show it, but the cone is so wide that whatever structure it’s seeing could be 20’ or more on either side of the boat. A frequent installation we see here in the northeast is a HW for trolling in conjunction with another model (H, M, or L) depending on the exact type of bottom fishing the owner prefers.
Here’s a good transducer reference from Airmar:
https://www.airmar.com/uploads/brochures/tilted-element-chirp.pdf
Personally I love my HW. Upgraded from a B60, incredible difference. I’m planning on adding a StructureScan 3D module, so that should carry most of the bottom fishing load in the depths that I frequent.
Thanks for the info, but one thing that is still unclear to me…Are the holes currently cut into the hull only the 2” circular hole (stem of transducer) and a the smaller bolt hole to keep it from spinning? Because I thought the hole was the size of the oblong fairing block? Or is that blue piece just sandwiched on? If it is just the two smaller holes then I understand.
Warthog, Most of my fishing is done within 60-200 ft of water. For rock fishing I’m usually drifting anyway, so the wider cone wouldn’t really be an issue. And offshore I’m chasing pelagics higher in the water column and trolling or flylining. So I think the B175HW would work for me.
Pelagic 2530, thanks for the info. Just need a little clarification on the size and shape of the hole cut through my hull with this current transducer???
Warthog, Most of my fishing is done within 60-200 ft of water. For rock fishing I’m usually drifting anyway, so the wider cone wouldn’t really be an issue. And offshore I’m chasing pelagics higher in the water column and trolling or flylining. So I think the B175HW would work for me.
Pelagic 2530, thanks for the info. Just need a little clarification on the size and shape of the hole cut through my hull with this current transducer???
The holes through the hull are just the two circular holes that are shown in the picture. The fairing block (if installed correctly) is cut on an angle to match the deadrise of the hull. One side is installed on top, one side on the bottom, effectively “sandwiching” the hull.
Thanks for the clarification, now that makes sense. As far as the distance between the two holes; according to the diagram, the distance between the centerline of both holes is 5.5 inches so that would make the outer edges closer to 6 inches. I would definitely have to fill and seal the smaller hole. I will search around for the correct size hole saw.
warthog5
Well-known member
That Starret holesaw is a nice setup....Starret is a top of the line tool...I have their stuff in a Vernier caliper and mic's.....But not their hole saws.
Having done a few and one of them recently......I took a pice a 18ga sheetmetal and wraped wax paper around it....a piece of 1/4/3/8 plywood would work also. You just want it small enough that it lays flat against the hull, but covers the hole......and gets Duct taped to the bottom of the hull.
With a 2in holesaw cut a plug, can be fiberglass or wood...glue it in the existing hole. Bondo or hot glue works well.
I have just Hot glued a scrap of plywood over the hole laid on the inside of the hull with a good flat fit and Hot glue.
Now you have a point for the centering bit to hold to make your 3 3/4in hole....
DO NOT use a Damn Rotor Zip and have a raggedy ass hole, as you will if you do.
The smaller 3/8 / 1/2 in hole fix it like any other hull repair 9 to 1 ratio.
Having done a few and one of them recently......I took a pice a 18ga sheetmetal and wraped wax paper around it....a piece of 1/4/3/8 plywood would work also. You just want it small enough that it lays flat against the hull, but covers the hole......and gets Duct taped to the bottom of the hull.
With a 2in holesaw cut a plug, can be fiberglass or wood...glue it in the existing hole. Bondo or hot glue works well.
I have just Hot glued a scrap of plywood over the hole laid on the inside of the hull with a good flat fit and Hot glue.
Now you have a point for the centering bit to hold to make your 3 3/4in hole....
DO NOT use a Damn Rotor Zip and have a raggedy ass hole, as you will if you do.
The smaller 3/8 / 1/2 in hole fix it like any other hull repair 9 to 1 ratio.
I was able to come up with this…the center hole saw is 2” and outer is 3 3/4” but the center one only sticks out about a 1/4” above the outer hole saw. I think that should be enough to get me started as a guide for the larger hole I need to cut. Let me know what you think. Also, what should I fill the smaller screw hole in the hull with? Would Marine Tex work? Is there a better product out there?
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Try West Marine epoxy thickened with one of their thickening products like microballoons...stuff is bullet proof!
warthog5
Well-known member
Cabisol is MUCH stronger and harder to sand than Microballons....Microballons are designed for mixing in when you are fairing a surface.
Use a countersink on both inside and outside the hull to give a better biting surface.
Cabisol is West System's 404 High Density.
