Age Unknown But Good Condition Bronze Thru-Hulls: Replace or Not?

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Jun 21, 2007
2,118
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Hi:

I pulled my 1980 Hunter out of the water a few days ago ... and managed to time it well to a series rare California heavy rain storms in April. The bottom looked rather good I thought considering the boat's been in the water now 2.5 years since I've owned it, and also that the bottom paint was past its prime already when I bought it.

I'm a first time haul-outer. I'm doing the work myself.

One decision item is thru-hull and sea-cock replacement or not. I don't know how long the exisiting thru-hulls have been on the boat. But all of my bronze thru-hulls pass the scraping/sanding test -- still show bright yellow metal with not a hint of pink. Inside, the bronze surfaces have some green tarnish in spots, but upon scraping, also only yellow metal with no evidence of pink. The wood stiffening/backing plates on the sea-cock side are still solid with no indication of wetness or softening. I've had no leaking at all at the thru-hulls.

Viewing the apparent sound condition of them, I'm thinking I'm safe to leave well enough alone and check again at the next haul-out a few years from now.

Opinions?

The sea-cocks are all working smoothly. Half are the marlon type. Half are bronze. The bronze ones are not displaying any pink metal, nor any signs of corrosion. But again age is unknown. Any need to replace?

Other projects are: -

-Sand bottom (got this done yesterday during a sunny rain break day) and repaint.
-Replace my generic 2-Blade prop with a more specialized sailing prop I'm hoping will help tame extreme reverse prop walk. Always looking for a challenge, I'm hoping to successfully remove the old prop using liquid wrench for a few days, then gear pullers I still have from my DIY Jaguar repair days, "precision" tapping with a hammer, and maybe gently warming up the prop with a propane torch. The boat yard folks with their hydraulic prop remover is the fall-back.
- My strut and cutlass bearing still look to be in very good shape.
- And of course, I'll take the opportunity to replace the zincs.

Thanks any comments and hints to help me get the most out of the haul-out.

rardi
 
Feb 26, 2004
23,356
Catalina 34 224 Maple Bay, BC, Canada
Happy haul out

Yeah, you got some great weather, eh? Coldest winter I ever spent here in 33 years.

Thru hulls - sounds like you've read Maine Sail's material - they sound good, why go looking for trouble? If it ain't broke...

Forget liquid wrench. Buy PB Blaster at Ace Hardware. It's like night and day. Prop pullers are the shops way to do it right. May not be worth your time.
 
Feb 6, 1998
11,760
Canadian Sailcraft 36T Casco Bay, ME
Rardi,

If they are as good as you say, leave them alone and keep on sailing..:)
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Cut and paste from woodenboat forum:

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Today, 03:12 AM


bluedog225



Senior Member


Join Date: Mar 2009


Location: Texas


Posts: 352​




Penetrating oils-comparison


This is a cut and paste from another forum. It may be old news but I have not seen it before. Just passing it along as it seems to be useful info.​



Tom​



***​



Here is some useful information for any of you that might end up rehabilitating a boat that sat in the water to long.​



Machinist's Workshop magazine actually tested penetrants for break​



out torque on rusted nuts. Significant results! They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment.​



Penetrating oil ..... Average load​



None ............ ......... 516 pounds​



WD-40 ............ ...... 238 pounds​



PB Blaster ............ ..214 pounds​



Liquid Wrench ...... 127 pounds​



Kano Kroil ............ 106 pounds​



ATF-Acetone mix... 53 pounds​



The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic​



transmission fluid and acetone.​



Note the "home brew" was better than any commercial product in this​



one particular test.



edit to add:




All that I know is what I read somewhere.
 
Jun 21, 2007
2,118
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Ross: Bummer for me that just a month or so ago, I brought my remaining stash of ATF to the recycling center. (No longer needed because we now have a manual transmission car and a Gen 1 Prius which also doesn't call for ATF). Thanks the info about the effectiveness of the penetrants.

Mainsail and Stu: Appreciated your opinions to save the time and get back out sailing as early as possible. As to the prop removal, I'm planning to spend no more than an hour setting up and trying. If its being stubborn, then I'll be happy to send the appropriate quantity of $'s in the yard's direction.

Raining cats-and-dogs for several hours now. And only 49F ... very cold for a California rain.
 

BobM

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Jun 10, 2004
3,269
S2 9.2A Winthrop, MA
Don't underestimate the pain that prop removal can be. I tried PB Blaster, heat and broke three prop pullers, including the yards puller, which I borrowed. I was rebuilding the drive train and finally managed to eek the prop (a 2 blade) past the rudder. Took the prop home on the shaft. Put a piece of appropriately sized tubing in my B&D work mate and honked on it with a 5 lb hammer. Popped right off then! I was driving back and forth 120 miles and it took me about three weekends to get everything apart in sweltering heat. Unfortunately the yard was pretty useless. More drinking than working and couldn't do much with a sailboat except launch it.
 

higgs

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Aug 24, 2005
3,736
Nassau 34 Olcott, NY
Through hulls rarely fail catastrophically. I have an '85 and have no plans to replace any of them. I would look into replacing gate valves, if you have any.
 
Feb 6, 1998
11,760
Canadian Sailcraft 36T Casco Bay, ME
Ross' info make me wonder a little because it seems all they were testing is torque. How about how fast or effectively it breaks the rust? I agree Kano Kroil is an awesome product but so is PB Blaster in my personal experience, though with Kano being slightly better. I have tried the ATF/Acetone thing as well as Coke Cola back before good penetrants were widely avaialble. WD-40 does squat for loosening rusted on nuts and Liquid wrench has never performed that much better for me.

My favorites are PB, Kano Kroil and a product called Thrust made by Castle. Sadly when I run out of Kano it is much easier just to replace it with PB cause I can get it at Wal Mart or any auto parts store. I do wish Kano was more avaialble other than mail order.
 
Sep 15, 2009
6,244
S2 9.2a Fairhope Al
i just bought some KANO KROIL last week abd used it on my mast head and it was awsom......you can order it from them direct and it was $12.00 total to my door ...but ya gota ask about the google special and they will send it to you for that price....pb blaster wouldnt touch the mast head ss screws but kroil did it very well .......

regards

woody
 
Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
Rardi, you have real seacocks? That could explain their good condition. The Cherubinis originally had 1/2" thru-hulls and could not accomodate a seacock. If you have seacocks then your thru-hulls were replaced with 3/4". Not sure why they would mix Marelon and bronze. Ran out of cash maybe.
 

Ross

.
Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Ross' info make me wonder a little because it seems all they were testing is torque. How about how fast or effectively it breaks the rust? I agree Kano Kroil is an awesome product but so is PB Blaster in my personal experience, though with Kano being slightly better. I have tried the ATF/Acetone thing as well as Coke Cola back before good penetrants were widely avaialble. WD-40 does squat for loosening rusted on nuts and Liquid wrench has never performed that much better for me.

My favorites are PB, Kano Kroil and a product called Thrust made by Castle. Sadly when I run out of Kano it is much easier just to replace it with PB cause I can get it at Wal Mart or any auto parts store. I do wish Kano was more avaialble other than mail order.

I have no idea if they waited minutes or days. Marvel mystery oil was the best we had when I was a kid. I find an impact wrench is often more effective than a breaker bar. Any oil and a torch seems to help if fire is acceptable where you are working.
 
Jun 21, 2007
2,118
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Hi Ed:

Probably I wasn't precise with the term... mixing up "sea-cock" as compared to a valve threaded on to the thru-hull. (Still learning to be precise with nautical terms, I am). The shut off valve for my engine's raw water intake looks to be 1/2" ID. But really I haven't looked at it critically in this respect. The boat has been owned by several people. From what I can tell, the original owner sailed it until the late 1990's. Then another owner for maybe four years. Followed by yet another for next maybe 2-3 years, most of which time it was on the hard looking for a new owner (me). Who knows the reasons for the various types of sea cock/valves? Even one owner may have been swayed to different installations by the latest trend, what was available at his chandelry, and cost.
 

higgs

.
Aug 24, 2005
3,736
Nassau 34 Olcott, NY
If your valves look like the ones on your garden faucet, they need to be replaced. A marine seacock will have a lever.
 
Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
Before I replaced the 1/2" with 3/4" thru-hulls I used ball-valves. I put an elbow on the thru-hull and then the ball-valve. This gave me the necessary threads because of the straight NPS threads(thru-hull) versus the tapered NPT threads(ball-valve). Only problem is getting the elbow tight and pointing in the right direction.

Even with the seacock I use an elbow to keep things low and horizontal. Picture is of seacock with elbow and 'T-valve'. Left goes to engine and right to A/C. Had to shorten a handle as you can see.
 

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Jun 21, 2007
2,118
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Higgs:

Thanks for the links with the information about proper fittings for thru-hull seacocks. Will refer again when I do need to replace. I certainly believe that the valves on my boat are marine grade bronze, not the home hardware type.
 
Sep 25, 2008
2,288
C30 Event Horizon Port Aransas
pb blaster wouldnt touch the mast head ss screws but kroil did it very well .......

regards

woody
That is very interesting. I didn't think anything would remove SS from aluminum. That make sme want to try kroil.
BobM-Are you using a 3 jaw puller or 2 jaw puller? Or is there something more specific that is better to use to pull a prop? I am polishing an extra prop for decoration/back up prop to to keep in my boat. I really regret hittting the hub with a hammer. But I didn't want to wait another weekend to get my gear puller. Guess what, I waited another week anyway and have dents in the hub to boot.
 
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