installing new unit

hey guys just bought a humminbird si and it looks like im gonna have to drill some holes to install. is there a special drill bit that i should look for so i dont crack the fiberglass?

I know what you mean about drilling holes in your boat. You didn’t mention what size of hole but you can buy a round hole saw blades that have a small center drill which prevents you from running off location, these will give you a clean hole. Take your time in drilling and make sure that there are no wires or other things on the break out side. Check your hardware store or lumber store for these drills. They also make a straight drills that has a starter point again to prevent you running off location, Good luck

Start with a smaller size drill bit to create a pilot hole. Then you can run the screw in to hold the transducer bracket onto your boat. Make sure you run some epoxoy or silicone after the bracket is secure, to prevent any slow leaks….

Put masking tak over the area you will be drilling. Mark the tape and drill in reverse for about 10 seconds, then forward. Apply light pressure and let the drill do all the work. The tape will keep the gel coat from cracking/splintering.

-J.

rip-n-lips
I have drilled several holes in my old Nitro from enlargi ng 2.5″ to 3″ vent holes with a hole saw. 2″ holes at specific angles to accomidate gimbal mount rod holders with a hole saw. 1″ and smaller holes with blade bits and high speed drill bits all without any problems. The two things I keep in mind at all times (1) makes sure what ever tool you are using is sharp and (2) keep your drill speed slow. You see when drilling in fiberglass it is like plastic it gets hot and starts sticking to your bit so keep it slow and stop once or twice to check the blade temperature. Good luck

I installed one on my Ranger 520 last year and there is a lot of things to consider as far a placment goes with that unit. What boat are you mounting it on???

I have seen it recommended to seal all holes or cuts with an epoxy to prevent moisture from entering the fiberglass and any hole creates a weak or stress point I believe they called it for a crack to potentially start.

Try using a brad point bit…I use them in woodworking, they have a center point, but also have a cutting edge on the outside of the tip to cut a clean hole without tearout. These bore a very nice clean hole in wood, fiberglass should be pretty close what with the fibers like wood.

If you are mounting the side imaging unit consider a mounting plate. I have just mounted it on my boat last week and you will definitly need to adjust it a few time to keep it from roostertailing. So if you buy a plate around 15bucks at a marine center you can screw up and only put 2 holes in the hull. Use 100% silicone I used aquarium grade it is cheep and will seal any chances for leeks. As hole size goes start small and go up. any bit type should work if it is sharp. Also if it is a side imaging transducer put it higher then the template shows. it doesn’t work on high speed anyway. put it so it is only in water when going slow. you can by a y connector and a high speed to do the rest.

i saw on a different site that some of the guys were mounting the ducer on their jackplate so i might try that. the thing im worried about is cracking the fiberglass when i mount the unit.

If you have a jack plate, that is the preferd place to mount it. I did not so I had to mount mine off to one side and on a ranger bass boat with a built in setback, I had to mounted along side of the motor mount. I usually have to trim the motor up about 2″ to get a really good view off the port side of the boat. You will need to glass a puck into the boat as well for higher speeds as the side imaging trans will not work as the boat comes up on plane. The only other thing I can say is if you have never used a SI unit, you will be amazed. Scott

I think you should just drill holes and ask questions later. Give me a call when you plan on doing this and I will come on up and help you out. Probably go down to my dads shop and grab the drill bits we need.