Drilling through the hull........need advice

Ok so this weekend I am going to install my make-a-wake ballast system. I am going to put in a vent line for all the bags and then with this system it only needs one empty line. So for now that will be 4 thru hull oulets above the waterline.

Ok I have never drilled through my boat before and I am extremely nervous. I need and pointers that I can get. Pics will be alot of help/ Also I wanted to know what you guys thought. should I place the thru hull above the rub rail or below?

Thanks in advance

I just talked to the MC dealer here about doing that and i was told to put duck tape over where you want to put the hole. drill a pilot hole with a small drill bit. then with your circular saw drill piece, drill in reverse first just to get a little groove going. once you have a clean groove you can put it in forward and finish out your hole. before all of that be sure to measure, measure again, and measure again to make sure you a have everything where you want it. i'm not an expert or anything...just what i was told to do.

Good advice from Jay. This is how I did my drilling for perfect pass. I had no chipping in the gel coat with this process.

Thanks for the info I will take some pics and keep you guys updated. Please if there is anymore info out there of pitfalls etc please post them. Thanks so much for all the replies

Just did the same thing last weekend. Here are a couple of things to check. The outside flange diameter of the thru-hull fitting is bigger than the hole you are drilling. Make sure you are below the rub rail far enough so the flange won't interfere with the rubrail. Below the rubrail is going to look better IMO.

I used plain adhesive tape; easy to make your marks. Use the inside plastic nut of the TH fitting as a template.

Bevel the outside edges of the hole with sandpaper. You want a smooth curved edge to avoid spider cracks.

don't know about the duct tape. I always read masking tape was the thing to use. I used the blue masking tape and put it on pretty thick when I drilled the thru hull for my ballast and PP. Also drilled holes for all of the tower bolts. 18 holes total and no chipping. Like stated above, bevel the holes and drill a pilot hole.

Masking tape, and definitely check the flange like Rich said.

I also meant masking tape; got my tapes mixed up.

Preston,

I am the guy that bought your Simers. Thanks by the way! I just finished up installing a ballast system in my VLX from scratch using those pumps. It works great and wasn't too bad to do other than tracking down each smaller component. I installed PP at the same time so after drilling the first hole the other four were cake. Just double check position, drill a pilot hole to be sure and go for it...........

Giles,
I am glad that you are happy with the pumps. I was just wondering the other day hiw the install went. I actually found the replacement impellars that come with the pumps the other day and if you send me an email hall@hhep.com">phall@hhep.com with you address I will send those to you no charge. Thanks for the advice about drilling the holes

Preston

Dang, you must be talented....I never heard of someone using a circular saw on gelcoat.

http://en.wikipedia.org/wiki/Circular_saw

Just busting your chops, I think you meant to say a hole saw. I've had great success installing scuppers, thru hulls, and additional cup holders with a hole saw, it's almost impossible to screw it up.

http://en.wikipedia.org/wiki/Hole_saw

In addition to the above, and it may be obvious to some but is worth saying, make sure you're coming through where you want to on the inside of the boat. I think it's actually better to drill out from the inside first with a 1/4" bit, and then come in from the outside with the hole saw.

spend the money to buy a good hole saw designed for fiberglass. It will give you a perfect hole with smooth edges. I think i spent $15 on one bit for my PP install. well worth it, my boat has yet to sink....

I would also say, lay out your entire system before you drill any holes. You may be looking around after everything is laid out and say "ahh I should have put them there".

As some stated, make sure you look where the hole will end up on the inside. I drilled from outside in, in case of 'blow out'. I used very light pressure when making the initial cut into gelcoat.

Also, you might want to sand/chamfer the holes after they are drilled to help reduce the chance of cracking later on.

One more thing to add, do not choose a spot that is in front of a Perfectpass paddlewheel or depth finder puck. The intake will disturb the water flow, and cause bad readings.

"I think it's actually better to drill out from the inside first with a 1/4" bit, and then come in from the outside with the hole saw."

I agree with this completely. You won't chip the gelcoat and you know the hole is going to be exactly where you want it to be.

Yeah, it might chip, but who cares? You're taking out a much bigger hole around it anyway.

Preston, I just drilled through the hull last night. I used masking tape over the hole. I drilled a fine bit through from the outside to make sure my measurements were accurate, they were, they I drilled the pilot hole using just the drill bit from the hole saw. I then "scored" the area with the holesaw in my hand from the inside to prevent chipping when the saw broke through. Under the boat, I attached the bit back on the hole saw, went in reverse for the first bit to get through the gel coat, then went forward. I recommend an electric drill. I pressed way to hard towards the end and popped through pretty hard, but it was fine. No dust whatsoever, possibly because my wife was holding a shop vac within inches of the hole. I then sanded or "chamfered" the edges of the hole, to get it super smooth. No chips on the gelcoat.

My 2" holesaw (for a 1 1/2 inch through hull scoop) was about $5 at Menards, the cheap kind are all you need, don't waste your money on the carbide tipped one.

Here is the pic before sanding.

WTF is this?

that is a molded in depression on the MC 205V hull. The mold is the same one used for the DD hull, and that spot is used for something on the DD, but not the V.

See where the masking tape is? That's where everybody puts the Paddle Wheel for PP. It's the only place you can put it where it won't catch turbulence from the depression on the Port side or the water pickup on the SB side.

(Message edited by Rich_G on April 20, 2007)

yeah, that's my marking for the PP paddlewheel. The depression is actually the raw water pickup scoop for the DD 205's.

Surprised I haven't gotten flamed yet for my corroded brass!

(Message edited by etakk7 on April 21, 2007)

Make sure you know what is behind where you're drilling. Dont wanna add fixing mangled wiring to the list.

Dremel tool....works pretty sweet. You need the RPM's to keep the Gelcoat from spalling out