through hull transducer

[trapper]

I appear to have asked many questions on their site without supplying the Grady group with very many answers, but here goes again. Have any 208 owners installed a through hull in there boat? I am considering it for my Furuno 1870F and would appreciate any tutorials as to location and tips on resolving any potential problems in the install. From my home work it looks fairly straight forward, but could use any tips you are willing to share. Much thanks, trapper

 

[DennisG01]

Yup, pretty straight forward. The directions that come with a unit are usually pretty good and thorough. You can typically download the owner's manual from the manufacturer's site ahead of time, if you wanted to take a look.

Are you doing an actual thru-hull, or a shoot-thru?

 

[trapper]

Thanks Dennis, Yes I am seriously thinking of cutting a hole. Ouch!

 

[journeyman]

Thanks Dennis, Yes I am seriously thinking of cutting a hole. Ouch!

Pick up a copy of this year's March issue of "Boating" magazine. There's an article on installing through-hull transducers. Page 48. You may pick up some pointers.

 

[DennisG01]

Thanks Dennis, Yes I am seriously thinking of cutting a hole. Ouch!

Nah, no band-aids needed. :mrgreen: I've got no problems with cutting a hole in a boat - but the cut edge should be beveled and then epoxy-sealed and then of course the whole thing sealed properly with top quality sealant. Depending on the style of thru-hull, I like to use a backer plate, too, for extra strength. That said, a solid fiberglass hull bottom will work extremely well with a shoot-thru style ducer. I've done both (along with transom mount) numerous times. My least favorite is the transom mount. The other two... it kinda just depends on the boat/application.

 

[Doc Stressor]

I put a 20 degree Airmar B60 in my 226 a few years ago. The job is simple and the Airmar instructions are clear. I drilled the pilot hole from the inside of the hull to be certain of the location. I mounted mine just aft of the freshwater tank, but any bilge location at least a foot forward of the transom and at least 3 inches from the center line will be fine. Cut the hole from the outside after taping the area to prevent chipping the gel coat. Since the hull is not cored on the smaller Grady's, you don't need to seal it with epoxy. Just mount the transducer with a non-permanent sealant in case you ever need to replace it. I used BoatLife LifeSeal, but 4200 is fine. I did not use a backing plate since the supplied thrust washer is robust enough.

The installation is very solid. I has survived 5 years of fork lift and trailer abrasion without any problems. The unit tracks bottom up to at least 30 mph if it isn't too rough.

 

[trapper]

Thanks guys for all the valuable input. Just trying to decide which thru hull transducer to use to match up with my Furuno 1870f. I am quite sure there is a big difference between the 600 and 1 kw transducers but so is the price. I see some of them hang on the outside of the hull, and some mount almost flush with the underside. I think I will be choosing the latter. Most of the fishing locally is between 200 and 300 ft. which can shallow up depending where around Vancouver Island one fishes. I guess you could say a "hole in one" coming up. Cheers with thanks, trapper

 

[journeyman]

I put a 20 degree Airmar B60 in my 226 a few years ago.

I believe that is the same one that was installed on my 258. Worked well.

Trapper, not that I know all that much about this subject but I do know they make these type of transducers with tilted elements to match your hull bottom. If this is the type you're going with, you need to orient the transducer properly so it is pointing down.

 

[Fishtales]

for what you are doing, I'd say the 600w is sufficient. I opted for a 1KW shoot thru transducer for my current boat as it was new and I didn't want to cut a hole in the hull. It was an easy no hole install. I've always had thru hull transducers prior and where you install is all glass, so you should have no issues.

 

[DennisG01]

Going along with what Jim said, make sure you get the ducer with the proper deadrise rating as there will usually be different models available for a specific range of deadrise's. Then, you follow the markings on the ducer as you install to match the deadrise of your boat. TAKE NOTE: You need to match the deadrise where you MOUNT the ducer - not just the deadrise at your transom (depending on how far from the transom you mount it, of course).

Even with a solid FRP hull, there's still merit to using epoxy. Chamfering and sealing the cut edge prevents possible water migration between the glass and gelcoat, thereby eliminating the possibility of delamination. The chamfering allows for better adhesion and also allows for a great "deadspace" area for your sealant. Most (including many manufacturer's) won't do this, but it is a better way to do things.

 

[trapper]

Thanks guys, just waiting awhile with the hope of the Canadian dollar picking up a bit. At the moment it is a big bite with pricing and shipping! Cheers, trapper

 

[seasick]

The 208 is a relatively short hull. That means that when on plane, the area that is fully submerged is pretty fat aft and not that large. The strainer for the live well and salt water washdowns are nearby and they may disturb the water. The more forward you place the thru hull, the more angle is rotates when getting on plane.
flow.
Accessing the bilge is also a real pain especially if you have the fresh water tank option. On my 208, my transom mount transducer works extremely well. It holds bottom all the way to WOT. I don't think I would try a through hull and find out that the spot I picked had issues. You can play with shoot through transducer since the hull is not cored.
Let us know what you end up doing

 

[trapper]

Yes seasick, there is an issue with location. I have made my freshwater tank area into a storage unit with a hinge and latch on the cover. Have a false floor in it and can access the hull there but.....it is beside the wash down pick up as you mentioned with a small area to work with. I have two transducers on the transome Furuno and Lowrance was hoping to tuck one inside. I loose the Furuno at speed, although the Lawrence seems to read bottom well at speed.Maybe being a little fussy. Not sure how much drag two transducers cause. I know they are suppose to skim the surface, but after many adjustments I have found they work a little better in the water than on the surface. I really don't believe there is any smooth water behind my 208 on the run. Thanks guys, still meditating on the next move, if there into be one. Cheers, trapper

 

[DennisG01]

I don't have the same boat as you and obviously I'm not there with you to physically look at. So I can't speak in regards to your access. But if you can locate the thru-hull forward of your washdown, that would be just fine. But I also wouldn't locate it too close, simply as a pre-caution for hull integrity. Obviously, a shoot-thru doesn't have the integrity issue and would allow you locate it closer to the washdown pickup.

FYI, for transom mounts... not necessarily "skimming". The leading edge should be slightly below the transom. The trailing edge should angled such that it is slightly below the leading edge when on plane.

 

[seasick]

I don't have the same boat as you and obviously I'm not there with you to physically look at. So I can't speak in regards to your access. But if you can locate the thru-hull forward of your washdown, that would be just fine. But I also wouldn't locate it too close, simply as a pre-caution for hull integrity. Obviously, a shoot-thru doesn't have the integrity issue and would allow you locate it closer to the washdown pickup.

FYI, for transom mounts... not necessarily "skimming". The leading edge should be slightly below the transom. The trailing edge should angled such that it is slightly below the leading edge when on plane.

I agree with the slightly below the water surface. In addition, I have found that tilting the ducer up in the back a notch off of level makes all the difference in the world. When level with the keel, I lose bottom at a about 20 or so knots. With one click up, I hold bottom all the way to WOT. Of course all bets are off if closely following another boat. The ducer does not like bubbles.