I am about to install an airmar low profile thru hull tranducers on my 04 257 Advance. Does anyone have any advice on how to do this?
Installing a low profile thru hull transducer
- Thread starter True Blue
- Start date
Had one on my Bimini, they work very well, i didn't do the install, i let the dealer do it. The only bad thing about, which i did not think in the beggining was that does nor read temp. and speed. Speed is not that important(you get that from GPS and pitot), but temp. is, so you have to install another sensor either thru hull or transom.
Sorry, was not on the Bimini(had in hull on that one), was on my inboard diesel boat.
Sorry, was not on the Bimini(had in hull on that one), was on my inboard diesel boat.
True Blue
Here is a post from THT authored by Peter Braffitt that may help you decide. Are you looking at a B-260 with high speed fairing or a flush mount tilted element model?
Default RE: Airmar B-260 Install
Warthog5, I have to say that you have put an impressive amount of pride and effort into the B260 install, and it is very well done. My estimation is that you will have very good readings at nearly all boat speeds, but the face of the transducer will still be exposed to some flow noise as well as the boundary layer of turbulence running down the hull. The result may be some loss of picture quality at speeds above 12-15 knots, but again, overall I believe you will be very satisfied.
I am not trying to change your mind on the install but I would like to share some observations we have made while developing the high speed fairings that we offer. For a trilered boat, high performnace fairings do present some challenges due to their size. The disadvantage if you trailer the boat is that they do protrude past the hull so the mounting location has to be selected with the boat on the trailer first, and then a suitable placement selected that will produce a clean flow of water to the transducer. One of the most important features of the fairing is that it does hang the transducer below the turbulent boundary layer of water that flows down the hull's surface. This will give very good bottom readings at all speeds, as cleaner water is flowing over the transducer. The thin leading edge of the fairing gently slices through and parts the water and it's length allows the water to straighten or "get used to" the change in flow direction that the transducer creates, lessening flow noise. Without a high performance fairing, that sudden change of direction that the water has to make creates flow noise that actually generates noise at the same frequencies that the sounder operates in. This will show up as snow on the sounder screen, forcing you to make gain changes, which reduces screen detail. You will lose the ability to see as much below the boat as you could if the noise wasn't present. I could equate this to having a conversation with a friend on the boat when my head's above the windshield (say above 15 knots), versus having that same conversation when I am well below the wind shield. When I'm above the windshield, the rush of wind passing over my melon cancels out a lot of the conversation and forces me to listen much harder . When I sit down, I can speak softer and also hear the other half of the conversation much clearer. The windshield is acting as my fairing. Another advantage is the fairing also has a slim trailing edge to allow the water to gently re-form again as it flows around the back of the transducer. This is also designed to reduce flow noise, just like the front, but it also acts to reduce the chance of prop ventilation or intake cavitation.
My closing comments are that I am not trying to discourage your install and I think you are going to be pleased with the results. If a person has the room for the fairing block it is certainly a much more cost effective install (because your time is worth more than the cost of the fairing) and the fairing has some measurable performance gains over a flush install. I have never seen a loss of vessel performance on a boat from 28 feet up if the location was properfly selected and the fairing properly installed. A few weeks ago I was at a very prominent fishing boat manufacturer's facility a few weeks ago (name withheld to protect my a__) to do an install on a B260 and fairing with them. I got involved because their engineering team felt that the size of the fairing would affect steering, handling and top speed on a 32 convertable being built for a customer (who had requested they install one for him). When I got to their facility we did an extensive amount of testing and measuring before the install to establish the performance of the boat. After the install we duplicated the exact series of tests and there was no measurable change in any performance parameter of the boat. The best news came from the customer who took delivery a week or so later. In the trip home with the boat, he was able to read bottom clearly, even with the boat at full boot (33 knots).
I am eager to hear of the results when you splash the boat. If I'm in the area I might even invite myself aboard to bend some rod tips with ya'!
__________________
Peter Braffitt
Business Development Manager
AIRMAR Technology Corp.
Milford, NH USA
pbraffitt is offline Report Post
Here is a post from THT authored by Peter Braffitt that may help you decide. Are you looking at a B-260 with high speed fairing or a flush mount tilted element model?
Default RE: Airmar B-260 Install
Warthog5, I have to say that you have put an impressive amount of pride and effort into the B260 install, and it is very well done. My estimation is that you will have very good readings at nearly all boat speeds, but the face of the transducer will still be exposed to some flow noise as well as the boundary layer of turbulence running down the hull. The result may be some loss of picture quality at speeds above 12-15 knots, but again, overall I believe you will be very satisfied.
I am not trying to change your mind on the install but I would like to share some observations we have made while developing the high speed fairings that we offer. For a trilered boat, high performnace fairings do present some challenges due to their size. The disadvantage if you trailer the boat is that they do protrude past the hull so the mounting location has to be selected with the boat on the trailer first, and then a suitable placement selected that will produce a clean flow of water to the transducer. One of the most important features of the fairing is that it does hang the transducer below the turbulent boundary layer of water that flows down the hull's surface. This will give very good bottom readings at all speeds, as cleaner water is flowing over the transducer. The thin leading edge of the fairing gently slices through and parts the water and it's length allows the water to straighten or "get used to" the change in flow direction that the transducer creates, lessening flow noise. Without a high performance fairing, that sudden change of direction that the water has to make creates flow noise that actually generates noise at the same frequencies that the sounder operates in. This will show up as snow on the sounder screen, forcing you to make gain changes, which reduces screen detail. You will lose the ability to see as much below the boat as you could if the noise wasn't present. I could equate this to having a conversation with a friend on the boat when my head's above the windshield (say above 15 knots), versus having that same conversation when I am well below the wind shield. When I'm above the windshield, the rush of wind passing over my melon cancels out a lot of the conversation and forces me to listen much harder . When I sit down, I can speak softer and also hear the other half of the conversation much clearer. The windshield is acting as my fairing. Another advantage is the fairing also has a slim trailing edge to allow the water to gently re-form again as it flows around the back of the transducer. This is also designed to reduce flow noise, just like the front, but it also acts to reduce the chance of prop ventilation or intake cavitation.
My closing comments are that I am not trying to discourage your install and I think you are going to be pleased with the results. If a person has the room for the fairing block it is certainly a much more cost effective install (because your time is worth more than the cost of the fairing) and the fairing has some measurable performance gains over a flush install. I have never seen a loss of vessel performance on a boat from 28 feet up if the location was properfly selected and the fairing properly installed. A few weeks ago I was at a very prominent fishing boat manufacturer's facility a few weeks ago (name withheld to protect my a__) to do an install on a B260 and fairing with them. I got involved because their engineering team felt that the size of the fairing would affect steering, handling and top speed on a 32 convertable being built for a customer (who had requested they install one for him). When I got to their facility we did an extensive amount of testing and measuring before the install to establish the performance of the boat. After the install we duplicated the exact series of tests and there was no measurable change in any performance parameter of the boat. The best news came from the customer who took delivery a week or so later. In the trip home with the boat, he was able to read bottom clearly, even with the boat at full boot (33 knots).
I am eager to hear of the results when you splash the boat. If I'm in the area I might even invite myself aboard to bend some rod tips with ya'!
__________________
Peter Braffitt
Business Development Manager
AIRMAR Technology Corp.
Milford, NH USA
pbraffitt is offline Report Post
Airmar B260 transducer install
Hey Peter,
I finished the install of the 20 degree tilted B260. After a lot measurements from the topside and bottomside of the boat I took the 4 inch hole into the bottomside of my Grady hull (this is not for faint hearted). After I got over this trama the rest of the install was easy for I ended up locating the transcducer in aft third of the hull and off of my trailer bunks.
My first trip was two weeks ago offshore of Charleston. We fished into 1200 feet of water and this was first time I've ever read my sounder this deep. I was thrilled!!!
Oh we also caught twenty mahi for the day. Now's the time to bend the rod.Thanks for a great product and improvement to my offshore fishing boat.
Hey Peter,
I finished the install of the 20 degree tilted B260. After a lot measurements from the topside and bottomside of the boat I took the 4 inch hole into the bottomside of my Grady hull (this is not for faint hearted). After I got over this trama the rest of the install was easy for I ended up locating the transcducer in aft third of the hull and off of my trailer bunks.
My first trip was two weeks ago offshore of Charleston. We fished into 1200 feet of water and this was first time I've ever read my sounder this deep. I was thrilled!!!
Oh we also caught twenty mahi for the day. Now's the time to bend the rod.Thanks for a great product and improvement to my offshore fishing boat.
Follow the directions that Airmar provides. It's very simple. I just installed one on a Grady 258.
I purchased a 20 Degree for a sweet deal and was reading thru directions and said something about using Fiberglass Cloth in the hole and kind of scared me a little about installing myself. I have a 1998 Voyager and am curious where exactly to put it. The directions say do NOT install on the flats. Pictures or diagrams would be especially appreciated. Thanks.
Bust it Big said:
The fiberglass cloth is only used for cored hulls, where another material, like balsa, is sandwiched between layers of fiberglass. Your Grady is straight fiberglass, so you don't have to worry about that.
Any clear area in your bilge, a few inch's off center should be fine.
You're better off de-coring the area around the hole and filling it with eopxy/cabosil if you have a cored hull, but we don't have to worry about that. With a hole that size you sould also sandwich a glassed board between the hull and the nut of the xducer.
Thanks for response. I assume by the responses that I have a pure fiberglass hull but am a little confused by the Grog's post about using a fibergalss board. Can you clarify what and why. I am feeling betteabout doing it myself but want to understand what I am getting into. WHat is best sealant to use...5200??
I also thought about the B260 but decied on an M260 instead. The B260 with fairing just seems too large for my needs (almost looks a small sailboat keel) 
Recently I installed a Furuno (made by Airmar) 235DHT-MSE for depth in shallow water and more importantly for accurate temperature readings needed for offshore fishing.
I know this is not what you asked, but I thought it might help you or someone else. I decided to drilll a 2" diameter hole through the starboard mounting flat on my 2006 Marlin for the 235DHT-MSE transducer. Of course I spent way more time measuring and double checking than actually drilling the 2" hole. I was expecting the hull to be at least one inch thick, much to my surprise it was only a little over 1/2" thick of solid fiberglass. I doubt the rest of the hull below the waterline is only 1/2" thick, but I thought I would share the infomation.
The boat is still on blocks and will be going in the water soon. I'll let you know how both transducers perform as soon as I get to test them.
Recently I installed a Furuno (made by Airmar) 235DHT-MSE for depth in shallow water and more importantly for accurate temperature readings needed for offshore fishing.
I know this is not what you asked, but I thought it might help you or someone else. I decided to drilll a 2" diameter hole through the starboard mounting flat on my 2006 Marlin for the 235DHT-MSE transducer. Of course I spent way more time measuring and double checking than actually drilling the 2" hole. I was expecting the hull to be at least one inch thick, much to my surprise it was only a little over 1/2" thick of solid fiberglass. I doubt the rest of the hull below the waterline is only 1/2" thick, but I thought I would share the infomation.
The boat is still on blocks and will be going in the water soon. I'll let you know how both transducers perform as soon as I get to test them.
Oh, and as far as sealant goes I researched and researched some more. The concensus was that 3M 4200 was the first choice, same sealing properties as 5200, just not quite as adhesive. The thinking is sme day that transducer will fail or need to be upgraded, when it does you (or the next guy) will be glad you used 4200. I am told removing a trtansducer mounted with 5200 can damage a hull.
Bust it Big.... the reason for not mounting the 20 deg transducer on the flats is because it is 20 deg that is to compensate for the deadrise in the hull bottom.
A zero deg transducer would be best on the flats.
I have the 260 and fairing block, fitted myself, on my 265 and have no handling or other issues at all. Reads clean bottom just like airmar say at 30 knots. I tried it first without the fairing and it had lots of interference on the screen at cruise speeds.
We are constantly on the lookout for bottom structure and bait between the coast and the reef so it is important to be able to read bottom at cruise speeds.
A zero deg transducer would be best on the flats.
I have the 260 and fairing block, fitted myself, on my 265 and have no handling or other issues at all. Reads clean bottom just like airmar say at 30 knots. I tried it first without the fairing and it had lots of interference on the screen at cruise speeds.
We are constantly on the lookout for bottom structure and bait between the coast and the reef so it is important to be able to read bottom at cruise speeds.
oh I forgot to say i mounted it right on the keel dead centre........and the hull thickness was 1- 1 1/2 inches thick solid glass.
Bust it Big said:
I found a pic of someone doing a thru-hull but your transdeucer is just bigger:
The "washer" is there to help distrubute the load over a larger area. A 4" hole is pretty big, the sealed plywood is there just to spread the load out over a larger area.