Drilling 3/4" hole in side of boat....Tips/Advice

[DaleH]

A couple of ideas and observations:

I use a hole saw to cut through the hull for the through hull. Dozens done and never a problem. Use silicone sealer and stainless hose clamps. Screw the pump to a piece of cutting board (or HDPE), to keep the pump upright and out of the debris. Replacement will be a breeze. If you get vibration, glue the HDPE to the hull with a dollop of silicone sealant.

... just be aWARE that not silicones are made for application or use on aluminum, where the curing agent can corrode tin ...

 

[LDUBS]

Deleted because (take your pick): Oops. Goofed. My bad. Reading comprehension problem.

 

[mervebitanem]

My bilge pump hose runs up to the top of the transom Tutuapp 9Apps Showbox where I have a 90 degree barbed fitting that points over the top of the transom.

 

[cyclops2]

I always put all bilge pumps in a piece of S S screen BAG closed at the top with a electrical Ty Rap. keeps all the tiny bits of fish line & other junk from clogging the pump. Bits of small baits also can be stopped.

I DO NOT ever wire any bilge pumps to the battery directly. Reason is heavy rains WILL WILL run the battery down to far and cause it to fail too quickly. I go to the boat and stand on a seat next to the control panel. Start the engine first to a fast idle. THEN turn on the pump. My small boat battery is about 8 years old & still fine.

 

[siemio]

great

 

[Crazyboat]

I too do not like putting holes in boats, the smaller the boat the less I like it. If you can take the advice given above about running the outlet over the transom that's the route I prefer taking.

 

[Still Afloat]

Thanks for the suggestions.

I will do so measuring since I just received the through hull. It could very well be a 1" hole that is needed.

I do have a step bit. It would cover the 3/4"-1" hole. I am considering using it, but thought the Bi-Metal hole saw would be more accurate.

I'll have to decide on which to use.

Yes, I will haver a beer....but maybe after.....so I don't %$#$ it up! :mrgreen:

Maybe have two beers after measuring, center punching the location and drilling a pilot hole. Personally, my measuring accuracy seems to decrease exponentially with the quantity of alcohol consumed.

I use hole saws for bigger holes but, the step bits really work well up to an inch or so and this would be my preference for this hole. I usually start from one side go half way through and then finish from the other side. This seems to cut down on rough edges.

A 3/4” or larger twist drill would make a mess if it grabs.

 

[stocrandy]

I will do so measuring since I just received the through hull. It could very well be a 1" hole that is needed.

 

[lckstckn2smknbrls]

I will do so measuring since I just received the through hull. It could very well be a 1" hole that is needed.

Do a test hole in a scrap piece of aluminum. See how it fits.

 

[Still Afloat]

Looks good. I prefer a Uni-bit for thinner gauge metal as well. They produce a clean and round hole. Hole saws need some clean up and they tend to walk a bit. It think because the pilot hole eggs out.

 

[airshot]

Hole saws are no different than other tools, if you have a good quality one, it will cut an accurate hole but if a cheap one....well you know how that will end. A word of caution, I would never use silicone as a sealant on a boat...it will fail. Use a good quality marine sealant and you will be good.