Best method to cut inspection ports?

[fatire]

Hi All,
Just wondering the opinion from those that have cut round inspection ports for various projects i.e. floatation retro-fit?

Seems to me a bi-metal hole saw would be way to go (4 1/8 for 4" ports) but a google site search shows very few references to using one.

I know from other forums that there are those that really like the fein type tools but I'd rather not make that investment now and was thinking a straight on drilling saw might be easier in that it would require little maneuvering.

Just bought a DSII and a loose port side jib track is forcing my hand on cutting her up.

My plan is to install a 4 incher in the forward end of the seat i.e. cutty wall.
(I just hope I'll be able to get my arm up past the in-seat cooler, but that's prolly another topic!

Thanks
Steve in NH

[ChrisB]

Steve,

I just installed an 8" port in my bow deck to access the stemhead fitting. I already owned a Dremel tool so I purchased the multipurpose cutting kit to go with it. It worked like a charm, making the cut in a couple of minutes.

[GreenLake]

A completely low-tech approach is to just drill closely spaced holes around the perimeter. I used a round file to "join" two or three of them and then some other tool, either a flat file or a hacksaw blade to complete the cut by removing the little "bridges" between the holes.

I could use my battery powered drill, so no messing with cords, and it did not take very long. The downside is that the hole will not have a straight edge - however, as it will be hidden by the flange of the deck plate (inspection port) neatness there is a very "hidden" virtue that I could live without.



I did some sanding with one of those sandpaper cylinders for my drill, to sand away enough of the little protrusions to get a better fit for the deck plate - I had drilled the holes on a rather tight circle.

By the time you do three holes that way, you may break even with a faster tool, if you count the time you spent driving to the hardware store to buy it

The rule for inspection ports is to fit the largest size that you possibly can. 4" is way too small for flotation work, 6" is iffy and 8" would be best.

[fatire]

Hi Chris,
Thhanks for the reply
I have a Dremel. Did you make use of the guide and I would guess you used the multi-purpose bit not the drywall bit?

Steve

Steve,

I just installed an 8" port in my bow deck to access the stemhead fitting. I already owned a Dremel tool so I purchased the multipurpose cutting kit to go with it. It worked like a charm, making the cut in a couple of minutes.

[fatire]

Thanks for your reply.
Point taken on port size, guess its back to WM for larger ports.
I can see your hole cutting technique taking more time then I want to spend though so I guess the dremel might be the answer for me.
Steve

A completely low-tech approach is to just drill closely spaced holes around the perimeter. I used a round file to "join" two or three of them and then some other tool, either a flat file or a hacksaw blade to complete the cut by removing the little "bridges" between the holes.

I could use my battery powered drill, so no messing with cords, and it did not take very long. The downside is that the hole will not have a straight edge - however, as it will be hidden by the flange of the deck plate (inspection port) neatness there is a very "hidden" virtue that I could live without.



I did some sanding with one of those sandpaper cylinders for my drill, to sand away enough of the little protrusions to get a better fit for the deck plate - I had drilled the holes on a rather tight circle.

By the time you do three holes that way, you may break even with a faster tool, if you count the time you spent driving to the hardware store to buy it

The rule for inspection ports is to fit the largest size that you possibly can. 4" is way too small for flotation work, 6" is iffy and 8" would be best.

[ChrisB]

Steve,

Yes, absolutely use the guide and the multipurpose bit. It will probably be fairly dull after cutting through fiberglass but it will do the trick. Go slow and use as just enough pressure to keep the bit cutting so you don't snap it off.

[fatire]

So one hole per bit would you say?

Steve,

Yes, absolutely use the guide and the multipurpose bit. It will probably be fairly dull after cutting through fiberglass but it will do the trick. Go slow and use as just enough pressure to keep the bit cutting so you don't snap it off.

[ChrisB]

You will probably be able to do two holes with one bit. Just be prepared for an unscheduled trip to HD or Lowes for a new on if it stops cutting!

[fatire]

FYI A bit of research seems to indicate a roto-zip tile bit might be the optimum FG cutting bit and it supposedly fits in a dremel.
Referenced was the Dura-cut ZipBit DC1 but it's .25" diameter so not sure about fit yet but maybe a tile bit that will fit my dremel is the way to go.

You will probably be able to do two holes with one bit. Just be prepared for an unscheduled trip to HD or Lowes for a new on if it stops cutting!

[GreenLake]

I can see your hole cutting technique taking more time then I want to spend though so I guess the dremel might be the answer for me.

Steve, I mentioned it, in case you didn't have a "better" tool handy. I would certainly not advise buying a tool just to cut three inspection ports (that's the likely number for a DS1). Subjectively, it didn't feel like it took very long...but I'll concede it's probably not the fastest.

[fatire]

I do appreciate your suggestion, and my reply was quite subjective in that I'm not the most patient when it comes to working with itchy fiberglass!
My solution ended up purchasing a Ryobi One roto-zip clone attachment for $39 and a tile bit for about $10. (I have sevaral other RO system tools and 3 batteries, so I could see this rotary tool coming in very handy) It even has a circular hole jig but that will only work on the bow tank due to the tightness of the two seat ports.
I just buzzed out the port side 6" port like a hot knife thru buttah!
That will allow me to repair the loose jib rack with through bolts and get sailing this weekend.
I saw no floatation at all in the port side seat, only the foam wrapped around the cooler.
I'll snap a few pics tonight.

I can see your hole cutting technique taking more time then I want to spend though so I guess the dremel might be the answer for me.

Steve, I mentioned it, in case you didn't have a "better" tool handy. I would certainly not advise buying a tool just to cut three inspection ports (that's the likely number for a DS1). Subjectively, it didn't feel like it took very long...but I'll concede it's probably not the fastest.