fairing block

[handball]

Just bought a standard fairing block by airmar and have a couple of questions regarding the block.<br /><br />My transducer is a 525st-msd triducer and there is a depression on the top of it for about a 5/8 dia male that is on the fairing, except on the transducer counterbore there is a 1/4 dia blob of black plastic sticking up that stops the fairing boss from entering it.I assume that this little black boss can be lowered so the airmar fairing can seat itself .<br /><br />Also the fairing has a raised circular area that is around the 2" hole that will not allow the transducer to sit flush with the fairing. This raised area looks like it might act as a seal,another thing that won't allow the transducer to seat completely is the transducer has about a 1/8 radius where the threads meet the top of the transducer.<br /><br />I am ready to finish mounting the transducer but want to make sure before I finish it.<br /><br />Bill

 

[ThomWV]

Re: fairing block

Bill,<br /><br />I have installed a few of those transducers, and its predecessor, the 520ST-MSD, using the standard Airmar fairing block. I have never seen one that the block didn't match up to the transducer perfectly. Sounds to me like you have a bit of a problem there. Also, the slight radius where the stem of the transducer meets the body should be matched by a slight radius in the fairing block. I wasn't real sure what you were trying to say with the alignment dimple, but they too should match right up.<br /><br />Thom

 

[handball]

Re: fairing block

Thomwv,<br />If you look into the relief in the transducer for the matching boss on the fairing there is a black 1/4 " dia boss that looks like some of the stuff used to fill the transducer for insulation was squeezed up.I think this should have been cleaned out by airmar and was just overlooked.<br /><br />Do you think I should remove some of the fairing around the area where the radius mates so that there is no gap between the transducer and the fairing? Have you usually been able to get them flush with each other?<br /><br />Bill

 

[ThomWV]

Re: fairing block

Bill,<br /><br />First off, yes, it is essential that the fairing block match the top of the transducer without a space. Now if you go look at my instructions on mounting a thru-hull you'll see that I use the stainless steel washer trick for my forward facing angle, but you'll also notice that I get everything perfect before I purposfully introduce that slight gap (less than 1/8") and then the gap is only at the heel of the transducer.<br /><br />Let me tell you what I would do if I didn't have a telephone. I'd cut the fairing block to match the transducer. The thing is that I do have a telephone and so here's what I suggest you do. Call Airmar and see what they have to say about it. While I'm certain that you can simply grind the offending knob off you'd be a lot better off hearing it from them than hearing it from me. I'm afraid I don't have their phone number here but you can get just as good an answer by calling their retail outlet, which is Gem Electronics. Gem can be reached at (843) 394-3565 and they are simply great to deal with. Some of the most helpful folks I have ever run across (next to 3-Rivers Marine Electronics and Consumer Marine Electronics). I'm sorry I don't have Airmar's number, my Palm Pilot took a dump on me and I lost it.<br /><br />Thom

 

[handball]

Re: fairing block

ThomWV,<br />I reasoned that if airmar designed this boss and c'bore for anti rotation , the blob of black insulation was an oversight and I removed it.<br /><br />I have mounted the transducer in the bottom for now and have run the cable thru the bilge and up to the consol.By the way Thom I have an almost impossibly small area to go from the bilge up to the consol, that is under the deck and over the starboard engine. I carved a piece of dowel stick about 4" long and 3/4" in dia. I tapered the dowel from the 3/4 dia on one end to about 5/16 on the other end, then drilled a hole thru its length.I then ran a piece of wire thru the narrow opening put the wire thru the narrow end of the dowel bent it at right angles on the 3/4 dia end , I then took the transducer cable and taped it to the 3/4 dia end of the dowel.This was then pulled up thru the narrow opening in the floor between other wiring and cables and up to the helm area. The tapered dowel really made this job possible as the end of the cable is large and bulky. Just thought I would mention it, might help someone else run their cables.<br /><br />As soon as the present bad weather passes I will drop the transducer and caulk it and the fairing block and finish up the assembly.<br /><br />Thanks again for all your help Thom,<br /><br />Bill