|Posted: April 23 2010 at 00:01 | IP Logged
I have a 3207 of the same era and I believe they were built the same, so your 3007 should be cored only on the decks. The hull is fiberglass, hand laminated with mat and woven roving in alternating layers. If you have a survey, it will give you the construction, but I can put money down our hulls are the same. Because of this construction, you should be ok with the "shoot-through the hull" transducer mounted inside your hull. Make sure the transducer shoots the proper frequency and sends the proper signal for your sonar/fish finder unit.
Here are a few things to consider: Location - place the new transducer on the other side of the hull (if the current is on the stpd side, install the new on on the port side). Do this in case you or the next owner wants to add a new thru-hull in place of the old. Forward looking sonars are getting cheaper and you or a future owner may want one of these units and the best idea is to install it where the old thru-hull is now. Make sure the new transducer is as far from the original thru-hull transducer so there is less chance of signal interference. Make sure it is at a location that has undisturbed water at planing speed (though some say shooting straight down may not always serve you well ast planing speeds - too shallow could be too late. It definitely needs to work at slower speeds). Installation Testing - you can test the installation by using a good amount of vaseline to "stick" the transducer temporarily to the inner hull. Run your boat over good known depths at multiple speeds to test. Installation - Once you find the best location for best use, you can then clean the bilge area and glue the transducer in. Many call for epoxy, but some say that silicone works well too or 3M 5200. If you use epoxy, you can create a dam of silicone, so the epoxy will level. The whole idea is to stick it so it shoots straight down and has no air bubbles below it. Contact must be absolutely positive. Air bubbles below it in the glue material or in that section of the hull layup will negatively affect the "shoot".
Hope this helps.