Use holesaw for inspection port?

Thread starter #1
Hi everyone, I have a few questions, i posted a message (http://www.sunfishforum.com/showthread.php?t=28959) not too long ago in regards to a SF I picked up.

I'm sure more questions will follow but for now, I am wondering if I can use a 4" hole saw to make the inspection ports? will it damage the teeth? or should I use a jigsaw? The reason I'm asking is because I have access to a hole saw but don't want to use it if it will damage the teeth, since it will be borrowed from my foreman.

How many inspection ports should I cut out? and how big? 4" or 6"? I found a place locally that sells the ports for $10 each, which is much cheaper than I've found online including shipping.


Any help would be appreciated and once again, thanks everyone for such a great and helpful forum.

Cheers
 
#2
I just did this twice (one in each boat). I used a 5" port and a good (but not new) fine tooth blade on a jig saw. I read online that it may take 2-3 blades. Took about two minutes to cut the hole and I didn't have any problems and the blade is the same as it was. It was no different than cutting plywood in my opinion. That was my experience, thats all I got.
 
#4
I would recommend the larger inspection port, the 6inch. It will make doing future work, where you may need to get a your whole are arm and whatever else in the hole, easier.

The number of inspection ports depends on what you are tying to do. Are you tying to fix a particular area or are you just trying to dry out the hull? Generally people put one port just forward of the centerboard. A second would generally go aft of the cockpit.
 
#5
I have used a jigsaw and a hole saw to cut inspection ports. From my experience, a hole saw is much easier, and creates a cleaner job.

Andy
 
#6
I think a holesaw might be a bit too aggressive and chip your gelcoat or maybe even too rough with the fiberglass.

I used a jig saw with a blade for metal. First I drilled a hole as a place to start and cut it out. I cut two 5" holes with the same blade.
 
Thread starter #7
Thank you everyone for the advice, but unfortunately I don't have access to a jigsaw..and..also I'm very afraid of messing up the hole, that's why the hole saw posibility came to mind.

Would a hole saw really tear of up fiberglass? or would it be a straight cut like Andy suggested?

can anyone else share if they have used a hole saw?

Thanks agian.
 
#8
I've put in at least several dozen 6" ports over the years using a hole saw. I takes a 1/2 drill to power that large a saw, but you get a dead clean hole.
To be on the safe side when purchasing the saw head take the port with you and the port extension should just slip inside the saw body. That gives you the maximum flange area for bolting.
And as an FYI do not install the port until you've finished all the interior work you added the port to do. The extra opening between the hole and the actual inside of the port makes for a lot easier reach.
 
#9
A question for those who have used hole saws-was it on newer boats?
My boat is a '74 and the gelcoat will chip from a drill bit with light pressure. I wonder if the age has something to do with it.
 
#10
I've always used a Rotozip, or spiral saw, for these kind of jobs. It cuts with what looks like a drill bit but is actually a cutting blade. This offers a very smooth method of cutting fiberglass, without all the bouncing around that a skillsaw or jigsaw can cause. I cut a 6" port in my '72 Fish last year, and the result was great--no chipped gelcoat, etc. It took a total of 30 seconds or so. You just have to work carefully since the Rotozip really does cut through fiberglass like the proverbial knife through butter!

I should add that these kind of saws are available at many places and by different names. Harbor Freight (if you have one around) has one pretty cheap:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=42831
 
#11
A question for those who have used hole saws-was it on newer boats?
My boat is a '74 and the gelcoat will chip from a drill bit with light pressure. I wonder if the age has something to do with it.
I have used a hole saw on 3 new boats (2004+). In the past I have used a jigsaw on a 1986 boat. Using the hole saw is a snap and clean. Even if there ends up being a few little gelcoat chips, they will be under the flange of the inspection port, and sealed. If you are really concerned with the chips, you can put masking tape on the area before drilling in.
 
Thread starter #12
Being new to sailing and boating in general, this includes any small crafts of any sort, I purchased a sunfish for $100CD to get a taste for things. Now here come the repairs.

So I went ahead and purchased 2 6" inspection ports to install along with some 3M Marine Adhesive/caulk. Now to wait for the 6 1/4 holesaw to be borrowed next week.

So I went ahead and took some pictures of the boat itself. It came with all the hardware including the ruder and dagger board. Now here come the questions. Does it matter if i screw the ports on or use nuts and bolts? I was thinking of using nuts and bolts with washers to support, just to make things nice and tight and firm. Any ideas?

Any thoughts on my purchase would be much appreciated, I am open to all suggestions and advice, and also criticism. :)

I am hoping to get out on the water with this little guy during the summer sometime, hopefully all the repairs will be completed.

Here's a link to the photo's of my $100CD sunfish.

http://picasaweb.google.com/MrGoodOne/Boat05182008?authkey=Gv1sRgCMvHq-7f_d6rdQ&feat=directlink
 
#14
I have used hole saws on fiberglass and gelcoat bathtubs/showers, from 1" to 4" with no problems, ever. (I am a plumber) I have cut several holes, in my sunfishs, ( for inspection ports) with hole saws and even with a roto zip. I like the roto zip method ( using the hole cutting jig) best. No need in buying ( or borrowing) expensive hole saws. The jig lets you cut what ever size you want!
If you are worried about chipping or jumping, first drill your center hole ( without hole saw) and then use the hole saw in reverse, until you cut through the gelcoat, then swich to forward to finish. Or I suppose you could do the entire thing in reverse, since the deck is only 3/16". Using reverse is just , less the chance of jumping out of control.
 
#15
I've always used a Rotozip, or spiral saw, for these kind of jobs. It cuts with what looks like a drill bit but is actually a cutting blade. This offers a very smooth method of cutting fiberglass, without all the bouncing around that a skillsaw or jigsaw can cause. I cut a 6" port in my '72 Fish last year, and the result was great--no chipped gelcoat, etc. It took a total of 30 seconds or so. You just have to work carefully since the Rotozip really does cut through fiberglass like the proverbial knife through butter!

I should add that these kind of saws are available at many places and by different names. Harbor Freight (if you have one around) has one pretty cheap:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=42831
I use a RotoZip for all sorts of cutting in fiberglass. They dull pretty fast on thick material, but work well on Sunfishes. I've cut seven ports on three boats and it cuts fairly clean. You have to be careful. The hole is a round as you are steady.

Wear hearing protection.
 
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