Through hull fish Finder for depth with verifier accuracy gauge called keel for those locations less than 8 feet deep. For speed take a moment during slack tide/current using your GPS against the amount of wake that you create from 3 to 12 mph to improve your ability to estimate speeds by eye. It is unlikely you will be harassed by a multitude of Slalom skiers for rides and you'll not be replacing repairing through hulls.
Seacock Quality... Replace?—Currently on the hard.
- Thread starter testingthewaters91
- Start date
I
I see. How about the 'shoot through hull' transducer? I already broke the previous transducer housing and ordered fiberglass to glass up the two thru hulls.
I had two “shoot thru“ depth transducers on my previous boat, a 1988 Hunter 33.5.
The original transducer, factory installed, was bedded in polyester resin at aft 1/3 of boat at entrance to aft berth. At some point, I replaced instruments & installed new transducer beneath V berth. Used method published in Sail magazine. Glassed a bell shaped PVC adapter to hull internal surface, filled the adaptor with mineral oil, & screwed the transducer into the adaptor. Worked well; no leaks.
The original transducer, factory installed, was bedded in polyester resin at aft 1/3 of boat at entrance to aft berth. At some point, I replaced instruments & installed new transducer beneath V berth. Used method published in Sail magazine. Glassed a bell shaped PVC adapter to hull internal surface, filled the adaptor with mineral oil, & screwed the transducer into the adaptor. Worked well; no leaks.
This will be my way forward. No need for the two monstrous 2" holes in the bottom of my boat, even if bedded carefully by me.
Will glass them up and use the shoot through hull transducer.
I would glass over the holes, use the shoot-through transducer for depth, and get a GPS for speed (at least SOG). So no holes in the hull for transducers 
Greg
Greg
At first I was scared of the glass work, but it seems like I have no choice. I've been studying up on how to glass the holes. I bought 17oz fiberglass cloth and West System Epoxy. It should be strong enough.I would glass over the holes, use the shoot-through transducer for depth, and get a GPS for speed (at least SOG). So no holes in the hull for transducers
Greg
I would strongly suggest reading the Gougeon Bross manual on basic frp repairs. I believe it can be d/l from their web site. A cheap angle grinder will make it easy to establish the slope around the holes, and then follow the instructions on cutting and preparing the layers of glass. If you have not worked with epoxy before, mix up a small ("one pump") batch and do some sacrificial lay up on some test pieces. Do this on a piece of Saran wrap or similar.) Once you see how long you have for the initial cure to start, you will start to gain confidence.
The irony is that you will only make mistakes after you first gain some initial confidence, and then also find that mistakes in glassing can always be ground out and better work can be done!
There are few real "secrets" to this. Just have a good rough surface to bond to (60 grit is good) and clean it with acetone first. Use vinyl gloves and wear old clothing like you would wear for painting. Actually, for general grinding, glassing, and painting I like an inexpensive "tyvek" (or similar) disposable suit. Those are not expensive and can last a long time if you are careful not to rip out a zipper.
17 OZ? Wow. That's heavy duty!
Good luck!
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Thanks for the thoughtful response.I would strongly suggest reading the Gougeon Bross manual on basic frp repairs. I believe it can be d/l from their web site. A cheap angle grinder will make it easy to establish the slope around the holes, and then follow the instructions on cutting and preparing the layers of glass. If you have not worked with epoxy before, mix up a small ("one pump"0 batch and do some sacrificial lay up on some test pieces. Do this on a piece of Saran wrap or similar.) Once you see how long you have for the initial cure to start, you will start to gain confidence.
The irony is that you will only make mistakes after you first gain some initial confidence, and then also find that mistakes in glassing can always be ground out and better work can be done!
There are few real "secrets" to this. Just have a good rough surface to bond to (60 grit is good) and clean it with acetone first. Use vinyl gloves and wear old clothing like you would wear for painting. Actually, for general grinding, glassing, and painting I like an inexpensive "tyvek" (or similar) disposable suit. Those are not expensive and can last a long time if you are careful not to rip out a zipper.
17 OZ? Wow. That's heavy duty!
Good luck!
I went with 17 oz cloth because I’m dealing with two 2-inch through-hull patches, and I want to ensure maximum strength and durability. From what I’ve read and heard, 17 oz biaxial provides exceptional structural integrity, often reducing the number of layers needed compared to lighter weights. I tend to err on the side of caution, especially below the waterline — overbuilding gives me peace of mind.
I had to grind down about 1/4" into the hull laminate to get the old flange out of mine. I started out with a thin "wet out" of thickened epoxy with high density filler because I found some voids in the laminate. Then had to build the laminate back up to about 1/2" using 2 layers of CSM and 6 layers of 10 oz cloth. Then I bonded the G10 backing plate to that with milled fiber ("kitty hair").
It was my first time also and was a little apprehensive. A couple suggestions:
Use what comes out when you prime the mini-pumps as your first experiment. It's not exactly proportioned but will give you a feel of what to expect in the curing process. Pour it out on a piece of plastic and test the consistency as it goes through the curing process.
Pre-cut everything so you don't waste time while it's curing on you.
Make certain the cloth is fully wetted out (translucent) but don't leave puddles of resin. I used a cut off chip brush and it made it easy to wet it out and move the cloth a little should you "miss". Use a spreader to gently work excess resin out as you go.
No matter what you do, epoxy seems to get everywhere. Disposable clothes (and gloves) are very important. Some plastic sheeting around where you're working helps a lot.
And by all means, read the West Systems instruction manual (around here, just about everyone who sells West Systems epoxy has free copies for the taking) and their "Fiberglass Boat Repair & Maintenance" book.
Just one newbie's take.
It was my first time also and was a little apprehensive. A couple suggestions:
Use what comes out when you prime the mini-pumps as your first experiment. It's not exactly proportioned but will give you a feel of what to expect in the curing process. Pour it out on a piece of plastic and test the consistency as it goes through the curing process.
Pre-cut everything so you don't waste time while it's curing on you.
Make certain the cloth is fully wetted out (translucent) but don't leave puddles of resin. I used a cut off chip brush and it made it easy to wet it out and move the cloth a little should you "miss". Use a spreader to gently work excess resin out as you go.
No matter what you do, epoxy seems to get everywhere. Disposable clothes (and gloves) are very important. Some plastic sheeting around where you're working helps a lot.
And by all means, read the West Systems instruction manual (around here, just about everyone who sells West Systems epoxy has free copies for the taking) and their "Fiberglass Boat Repair & Maintenance" book.
Just one newbie's take.
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Hey all,
I’m in the middle of a full seacock and through-hull overhaul on my 1981 Hunter Cherubini 30. So far, I've removed the old valves, sourced proper Groco seacocks, and prepped G10 backing plates. I’ve got the epoxy, fiberglass, and all the materials lined up. One of the through-hulls was installed cleanly but without a backing plate — I’m planning to get a step wrench to pull it so I can do it right.
While inspecting the aft compartment behind the aft berth, I noticed something that surprised me: on each side, there’s a small through-hull exiting the hull — just a couple of inches above the static waterline — with a white corrugated hose leading down from the scupper drains. These look like they could dip below the waterline when heeled. No valves, just open drains. I’ve attached pictures showing their position.
I'm considering options here:
Leave them as-is (since they're technically above the static line)
Glass them over and relocate higher
Glass them over and re-drill with proper seacocks
I’m not planning to add a valve to the engine exhaust outlet — I know opinions vary, but I’ll probably leave that one alone.
For reference, I’m glassing up the old paddlewheel and transducer holes completely, and replacing all the remaining through-hulls that had ball valves with proper flanged seacocks and new bronze fittings.
Just looking to hear what some of you would do with these aft scupper drains. Anyone tackled this before? What are your thoughts on best practices here?
Thanks in advance — appreciate the wisdom on this board.
I’m in the middle of a full seacock and through-hull overhaul on my 1981 Hunter Cherubini 30. So far, I've removed the old valves, sourced proper Groco seacocks, and prepped G10 backing plates. I’ve got the epoxy, fiberglass, and all the materials lined up. One of the through-hulls was installed cleanly but without a backing plate — I’m planning to get a step wrench to pull it so I can do it right.
While inspecting the aft compartment behind the aft berth, I noticed something that surprised me: on each side, there’s a small through-hull exiting the hull — just a couple of inches above the static waterline — with a white corrugated hose leading down from the scupper drains. These look like they could dip below the waterline when heeled. No valves, just open drains. I’ve attached pictures showing their position.
I'm considering options here:
Leave them as-is (since they're technically above the static line)
Glass them over and relocate higher
Glass them over and re-drill with proper seacocks
I’m not planning to add a valve to the engine exhaust outlet — I know opinions vary, but I’ll probably leave that one alone.
For reference, I’m glassing up the old paddlewheel and transducer holes completely, and replacing all the remaining through-hulls that had ball valves with proper flanged seacocks and new bronze fittings.
Just looking to hear what some of you would do with these aft scupper drains. Anyone tackled this before? What are your thoughts on best practices here?
Thanks in advance — appreciate the wisdom on this board.
Attachments
The “scupper” drains from the cockpit typically are not valved on production boats. On my O’Day 322, the scupper drains are just on plastic thruhulls. Mine are certainly below the water line when sailing or motoring. I also have a few sink drains that are 1” above the water line and they do not have valves either. I assume the theory is that of the hose broke or something, you could stop and fix it and it would not sink the boat. But, you could replace the thruhulls (mine are plastic) with a skin fitting and valve (like the various ones you are upgrading to the Groco valves). Adding the Groco in these areas Is really overkill.
As far as relocation, I am not sure if you would have enough slope to empty the cockpit if you took on a lot of water and were heeled over….the low drain is the one that needs to rid the water…
Greg
As far as relocation, I am not sure if you would have enough slope to empty the cockpit if you took on a lot of water and were heeled over….the low drain is the one that needs to rid the water…
Greg
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,177
Buck Algonquin makes a step wrench that is used to install and remove through hulls.
Or you can make you own.
We did in my friends shop out of some scrap aluminum.
with a big wrench outside the hull this worked great. Both through hulls were 3/4”.
Or you can make you own.
We did in my friends shop out of some scrap aluminum.
with a big wrench outside the hull this worked great. Both through hulls were 3/4”.
I went with a poor man's step wrench when installing my thru hulls.
Turns out a brake adjuster tool for cars can used to grab a thru hull to spin it on or hold it while the something is being spun on to the threads from the inside.
Yes, the angle isn't a true 90 degree to the handle but once my wife learned how to "lock it in" she could hold the thru hull while I tightened the valve onto it from the inside of the boat.
I found the brake adjuster tool on Amazon.
Turns out a brake adjuster tool for cars can used to grab a thru hull to spin it on or hold it while the something is being spun on to the threads from the inside.
Yes, the angle isn't a true 90 degree to the handle but once my wife learned how to "lock it in" she could hold the thru hull while I tightened the valve onto it from the inside of the boat.
I found the brake adjuster tool on Amazon.
I ended up ordering the thru hull wrench on Amazon. It should arrive next week. It was about 80 dollars.
Please, please, please don't use wood. It WILL rot unless you're usng an exotic and if you're going to go to that much trouble, use the optimal material, which is G10.
G10 can be worked with standard woodworking tools. I have some experience with this. The plywood backing plates were rotting so i replaced the throughhulls and backing plates. Maine Sail's article was extremely helpful. My writeup is here: Installing through-hulls in a Yamaha 33.
The guys at West Marine were telling me everyone uses Starboard these days because it's all they carry.
The problem with Starboard is the sealant doesn’t bond well to it, so it can form leaks due to physical separation resulting from hull stresses and material expansion/contraction with temperature changes.
Yes fiberglass (including G10) is ideal, but oak that’s been sealed with a coat of epoxy resin will last as long as the boat. No need for exotics.
G10 is an engineered form of fiberglass that has very high density and strength It is ideal for situations where resisting very high loads is a requirement (e.g. base for mounting an autopilot ram with forces over a thousand pounds ) or where you want to use a tap to screw bolts into it without backing (e.g. engine mounts). It’s overkill for a sea cock backing plate and expensive to buy if you don’t have a scrap piece available. It also will dull your woodworking tools pretty quickly.
