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Locations of inspection ports and mast step repair

David Jenkins

New Member
I may need to purchase a mast step kit but first I want to try to make repairs to my mast step without buying the kit.

My first task is to cut at least one 5.5" inspection port. I want to make sure that the hole(s) I am about to cut will be either completely inside the area that the repair kit would cover or completely outside of that area.

I cannot find dimensions of the deck piece that comes with the various repair kits. Does anyone know those dimensions?

By the way, there are three problems with the mast step on this newly-acquired 1973 Laser: water leaks out of the mast step as fast as I can pour water into it; the top of the tube (where it meets the deck) is not perfectly round; and the mast step is only nine inches deep, not 14 inches as I expected.

I may be able to solve the first two problems without ordering a repair kit. But I am not sure that I can solve the last problem without ordering a new tube (and I guess that means ordering and using everything that comes with a mast step repair kit). Right?

When I shine a light into the mast step I see what appears to be a thick disk at the bottom (i.e., there is a 1/16" space between the "disk" and the cylindrical walls of the tube).

I have drilled an inch or so into this "disk" and it is definitely resin, not wood or metal. My daughter's hand is small enough to reach down to the bottom of the tube but she cannot make the "disk" move in any direction.

Here is my theory: years ago someone poured about three cups of resin into the tube to stop a leak. The repairman may not have cleaned the tube with acetone or anything else prior to pouring in the resin. Over time the turning forces of the mast caused the resin to crack where it met the tube.

Here is my hope: since the resin "disk" is cracked on the sides maybe it has cracked on the bottom as well. In that case there might be a way to get it out of there.

One more piece of information: both the deck around the mast step and the hull area immediately below the mast step have been repaired by someone in the past. However, there are no inspections ports in the deck. My guess is that there was a severe mast step failure in the past and the repair was made by opening up both the hull and the deck. It is unfortunate that the repairman did not use (and leave in) inspection ports.

Thank you in advance for any advice that you may have for me.


Wow, if boats could talk.... Three cups of resin in the mast step--this is a new one. There are many people here better able to give you advice than me, but here's what I've got. I'm picturing the cableman's drill. Maybe you can rent one to drill out the rest of the resin. I don't think that it is a problem that the step is not circular, mine's not on my '03 boat. Finally, use the SEARCH feature here. There are several really fine threads with photos on mast step repair and port placement.


1)With the Viking brand, the lid is a perfect template for the cut-out.

2) Oval is normal

3) Sorry to hear about the 9" tube. There is a slight chance you can punch it out. I'd drill a 1/2 to 3/4 hole thru the bottom of the boat, and into the filler plug a little bit. Then inset a blunt 1/2 bar of steel. Strike that with the biggest hammer that you have. The tube walls are smooth, likely dirty, and tapered in your favor. However the mast probably wore thru the bottom, so the poured fill probably has a sort of flange on the bottom, that you won't be able to budge.

Good luck


David Jenkins

New Member
Thanks, Merrily. I will investigate the cableman's drill.

Vtgent49, I like your suggestion of drilling all the way through then flipping the boat upside down and using that small hole as access to punch the plug out.

Regarding the inspection port, my question is, if I use the Viking lid to cut a hole for an inspection port near the mast step and then later determine that I need to purchase a mast step kit with its adjoining deck area, how do I know that the inspection port is not going to be right on the line where the original deck ends and the new deck (from the kit) begins?


Try googling electrician long drill. Don't forget to try TLF's Search feature too for information on port placement and mast step repair.

David Jenkins

New Member
Merrily, do you mean long drill bit? That is what I used to drill into the resin at the bottom of the tube.

Regarding using the search feature, I spent several hours reading through many helpful threads before I posted my questions. I do not believed that they have been answered anywhere on TLF.

I am sure that someone has put in inspection ports AND installed a mast step kit. If so, did you install the inspection port on the portion of new deck supplied with the kit or did you install the inspection port further away from the mast (in the original deck surface)?

David Jenkins

New Member
Thanks, Greg.

From looking at those photos and reading many helpful comments on this forum and elsewhere, I have concluded that it would not be a good idea to install an inspection port next to the mast step if there is a good chance that the mast step repair kit will be needed.

The general consensus is that the structural integrity of the mast step might be weakened if an inspection port were installed closer than 10 inches from the mast step (edge of mast step to edge of inspection port). I do not believe that you would have sufficient room to install even a 4-inch inspection port in the area of deck that would be replaced by the mast step kit, should that be necessary. And to go outside the deck area that would be replaced by the deck that comes with the kit you would need to go several inches outside of where the future seam might be, and so the edge of your inspection port might need to be about 20 inches from the mast step. This would make repairs to the existing mast step difficult unless you had arms like a gorilla.

By the way, I managed to remove the five inches of resin that were in the bottom of the mast step. So now I just have to make the mast step water tight. It appears that a new mast step kit will not be necessary.