Hull Construction

Mina

I’m looking to replace the non working Lowrance 3200 currently on the boat with something newer. My guess is that this is the original. I looked at the Garmin ECHOMAP g3 74cv. FF/Plotter on sale at West Marine for $549.99 until the 17th. I discussed this with the Mechanic I’ve been using and now have a question regarding the hull.  Does anyone know if the the Hull is corded or all fiberglass?  Any suggestions on other replacement options would be appreciated.

skennelly

Pretty sure the hull is solid fiberglass below the water line.

Echomap are good units.

aero3113

My 2001 242 was plywood between fiberglass/gel coat.

aero3113

Mina

Wow, what is the hole for?

aero3113

@Mina , it was for easy access to the starter, LoL!
I installed a new chart plotter, I drilled the hole for a transducer.

PickleRick

Wow, i thought most manufacturers had converted over to a solid hull below the water line.  My 1977 san juan saiboat has nearly 2 inches of solid fiberglass hull. I don't know if applied to all carvers but the santa Cruz model stopped cored hulls in the late 70s. 

My 235 has no wood core in the hull, i can see light shining  through the fiberglass in the spots I've removed blisters(gel coat removed in those spots) in the front of the hull.  Im letting it dry all winter before painting/preparing this spring. I noticed light through the fiberglass when i ripped out the carpet.

PickleRick

I have a shoot through hull transducer mounted in my sailboat but she doesn't see over 10 mph.   

To test if shoot through works for you put a zip lock bag full of water against hull then transducer on top of bag of water.

Many people make the mistake of mounting shoot though with silicone.  Any air bubbles will kill the signal, what i found was put a wax toilet ring firmly against boat hull. Set transducer inside toilet ring, fill toilet ring almost full of water.  Might need to add water once a season.  

Transducer cant be bouncing around, i used a little 4200 to glue the mount flange to the side of the storage compartment under the cockpit,


I also do this in my fishing kayaks as i dont want to buy a depth finder for each one,  just transfer it from boat to boat.

I've never tried this in a planning hull. My new garmen for the rinker is transom hung as designed.

Mina

So since I’m reluctant to drill through the hull due to the cost of the haul out what options do I have?

PickleRick

@Mina how are your local connections?  

Borrow a lift or trailer?  

Is your transducer transom hung or thru hull?




If you want temporary you can do what i suggested, fill a zip lock bag full of water, place bag down on flat spot of hull.  Push transducer against bag, no air bubbles!    See if it reads.  If it reads then push a 7 dollar toilet wax ring in that same spot, it should make a nice little wax pool to put a little water in.  Fix the transducer temporarily inside that ring so it doesnt rock or bounce, you can use the side of the wax ring to help mold it into place, just be sure water can easily make its way under it so leave some if it exposed.


If it works wait until pull out to install. For fancy sonar/chirp it may not pick up on fish, it may just read botttom and depth.  

You want to find a place in hull that is solid fiberglass, no wood core or voids, as flat as possible.  

Ive seen sailors 5200 a 2 or 3 inch piece of pvc to the hull and then drop the transducer into the center.  Then fill the little 2 or 3 inch tall piece of pvc about half full of water, just enough to drown the part of the transducer that would be under water.  For a temp install use marine silicone as a glue for the pvc pipe and it cleans back up easily if you don't like the wax ring idea. No need to find a mounting support if your transducer fits snuggly inside the pvc pipe.  Just needs to be tall enough to give support to keep transducer upright.  


Sailors dont like holes in hulls,  especially the racing boats with glass smooth hulls.  These guys usually have deep keels and need to keep an eye on depth.

Hope this helps as a temporary solution.  

Willhound

Just do an external transom mount. Two easily sealable screw holes and you're good.

PickleRick

@Willhound, still need it out of water to install a transom hung transducer.    

If it was an outboard you could beach it and wait until low tide but wont work with and i/o. Atleast not mine, my outdrive wont raise high enough to beach the transom.


I have the fresh water 4.3 version of that, it came with a transom hung transducer.

Only the center section of my transom is cored, the hull is a little over half an inch solid fiberglass.  I installed it into the solid area so no chance for water intrusion of the wood core i worked so hard to replace.    

MarkB

aero3113 said:

@Mina , it was for easy access to the starter, LoL!
I installed a new chart plotter, I drilled the hole for a transducer.

Is that through the transom or the hull? 

aero3113

Through the hull

reneechris14

@aero3113 Its a good thing you sold that boat it had a hole in the bottom 

PickleRick

Flex seal can fix that

aero3113

LoL, it took me a while to get myself to drill that hole!

Mina

The thought of cutting a hole like that in the hull really makes my stomach turn.  According to the gal at WestMarine it’s not necessary with the Garmin ECHOMAP.  I hope she’s right cause cutting holes in the bottom of a perfectly good boat is like jumping out of a perfectly good airplane.

PickleRick

If sealed and installed properly it will never be an issue.  

aero3113

You can see in this picture that it was installed next to the original depth transducer. The new one was for depth and sonar. They ran on different frequencies so no issues with them being so close.

MarkB

Mina said:

The thought of cutting a hole like that in the hull really makes my stomach turn.  According to the gal at WestMarine it’s not necessary with the Garmin ECHOMAP.  I hope she’s right cause cutting holes in the bottom of a perfectly good boat is like jumping out of a perfectly good airplane.

Most sonars have the option for a through hull transducer (installed flat with epoxy to floor in bilge, and they actually can read much better than direct transducers in most cases (if installed properly) because they turn the entire hull into a transmitter and receiver.