Hauling to bottom paint - What else should I be doing

I'm hauling my boat next week to bottom paint, replace the stbd rudder log, replace 2 thru hull valves, replace zincs, wax the hull, and re-pitch the props.*

* Anyone have suggestions on anything else I should consider doing while the boat is on the hard
* Any suggestion on a web site that describes the process of preparing the bottom for painting.


Thanks guys and gals.

Curious. Why are you having the props repitched.

SD

you already note that you are replacing two through hull valves but I'd take a look at all the rest.* We had two we knew we wanted to replace based on how corroded they were*on the inside.**Once the boat was hauled we saw more that looked BAD.* One was so clogged there was barely a pin hole in the middle of it.*

hope everything goes well for you!

You might want to check your bonding system for continuity while the boat is out of the water. When it's in the water the water will connect the through-hulls so you might not be able to tell if the bonding to any one of them is intact. We're going to have this done on our next haulout which should be in December if I can ever get a break in my work schedule to do it.

Lube all the thru-hull valves.

skipperdude wrote:

Curious. Why are you having the props repitched.

SD

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The engines turn 2750 rpm at WOT and should be turning 2900-3000. Over proping is the #1 reason for early engine failure.*

Marin wrote:


You might want to check your bonding system for continuity while the boat is out of the water. When it's in the water the water will connect the through-hulls so you might not be able to tell if the bonding to any one of them is intact.


Good idea, but how would I do this??? Damage due to*electrolysis is why I'm replacing the rudder log.




Pineapple Girl wrote:


you already note that you are replacing two through hull valves but I'd take a look at all the rest.


Good point and I will. The valves are being replace due to a broken stem that connects the handle to the valve. I close all my thru hull valves when the boat is not being used so they are exercised frequently, probably why the stems broke!




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-- Edited by timjet on Wednesday 10th of November 2010 06:56:38 PM

-- Edited by timjet on Wednesday 10th of November 2010 07:08:50 PM

This statement was on the deficiency report of my survey when I bought the boat last May:
The belly of the hull is covered with dime to quarter size blisters, 90% are along the starboard belly of the hull. Note: These blisters do not appear to be structural.
Recommend: Having a competent person inspect and repair all blisters as needed at some point in time to prevent further possible damage from osmosis.

Anyone care to comment on the process necessary to repair this.
Thanks

timjet wrote:

*
Marin wrote:


You might want to check your bonding system for continuity while the boat is out of the water. When it's in the water the water will connect the through-hulls so you might not be able to tell if the bonding to any one of them is intact.


Good idea, but how would I do this???

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We're going to have the electrical shop we use do it, but I assume it involves checking the continuity with a meter and real long leads*between every through-hull, the rudders if they're metal, the zincs, the props, etc.** If your boat's throughhulls are plastic then they won't be connected to the boat's bonding system, of course.

-- Edited by Marin on Wednesday 10th of November 2010 07:11:52 PM

timjet wrote:

This statement was on the deficiency report of my survey when I bought the boat last May:
The belly of the hull is covered with dime to quarter size blisters, 90% are along the starboard belly of the hull. Note: These blisters do not appear to be structural.
Recommend: Having a competent person inspect and repair all blisters as needed at some point in time to prevent further possible damage from osmosis.

Anyone care to comment on the process necessary to repair this.
Thanks

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I had a blistering problem.* My marina manager called in a few experts.* Some said to dry and patch the area, then paint, one quoted $6,000 to re-gelcoat the entire underwater surface.

I called the surveyor who surveyd the boat when I bought it two years previous.* He had noticed some blistering and noted it.* He suggested having the blisters filled and painted but taking photographs before and after, then checking at the next haulout to see if the problem is getting worse.

I did what he suggested.


*

timjet wrote:

This statement was on the deficiency report of my survey when I bought the boat last May:
The belly of the hull is covered with dime to quarter size blisters, 90% are along the starboard belly of the hull. Note: These blisters do not appear to be structural.
Recommend: Having a competent person inspect and repair all blisters as needed at some point in time to prevent further possible damage from osmosis.

Anyone care to comment on the process necessary to repair this.
Thanks

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Yes... Save your money. If they are only cosmetic, they won't sink your boat. My hull is COVERED with blisters and unless I win the lottery, I won't repair them (that is unless they get worse... and it's unlikely they will). To repair it, they will plane off the top layers of gelcoat and recoat... Then, when they put it back in the water... the blisters could STILL come back.

There are a lot of opinions on both side of this issue, but unless you have a lot of spare coin or there is a buyer who's broker is giving them skewed advice. I'd just let them be, monitor them over the next years, and spend that money somewhere else.

Check the cutless bearings

I had the gel coat peel and re finish on a previous boat, I can tell you it is a long, expensive and drawn out proceedure, best avoided unless really needed.
Steve W.

Gonzo,
I don't agree w your see no evil attitude about blisters.
I grind down to the fibers on my hull wherever I see weeping or anything else that looks blister-like. Typically my "grinds" are about 3/32" to 1/8" deep and 1/2" wide and 5/8" long. I try to dry the work but weather usually dosn't allow much drying. Then I mix some epoxy (thickened) and cut a small brush short (for stifness) and coat all the "grinds" w one or two coats as thick as I can get them. Then I sand the slick surface of the cured epoxy quite well (for adheasion) and apply anti-fouling paint. I have no blisters that are "raised" (bumps) anymore**** ...just seeps. Most often small amounts of dark watery fluid leaks out of very small holes (less than 1/16" dia(most less than 1/32")). I think, Gonzo, that it's worth the effort to wage a little war and try to limit the water ingression into the hull. Two photos show the "grinds" on the port side and the nice smooth surface when done.

Would you be willing to pay someone over $200/ft. to do that? Would you be willing to do that many, many 100's of times just for cosmetic blisters? If one starts to look evil, I'll tackle it.

Sure... If it were just a few or if I had owned the boat from the start and stayed on top of the effort, maybe. But like I said, blisters don't sink boats, but they'll quickly sink a bank account. It's not that I wouldn't LOVE to have a nice flat bottom, it's just not a good cost versus benefit investment. IMHO

-- Edited by GonzoF1 on Wednesday 10th of November 2010 08:11:26 PM

Thanks everyone for your comments.

Steve, about the cutlass bearings of which I have 2 on each shaft, can you really inspect them without taking the shaft out?

I'll post pictures when I get the boat out early next week of the blisters and get your opinions.

Thanks again folks.

Regarding cutless bearings, what you're looking for is if they are moving out of their struts. For example if you see that a cutless bearing (rubber bushing if you will) has slipped backwards or forwards and part of it is hanging outside the bearing holder that is a failure in the process of happening. The cure is to pull the shaft and replace the bearing, making sure the alignment of the strut and shaft is correct and is not the cause of the bearing creeping out of the strut.

If a cutless bearing has worn to the point where the shaft has "wiggle" room where it runs through the bearing that's another indication that the bearing needs replacing.

If when the boat is out of the water the bearings are all properly in place and tight around their shafts they should be fine. There is no need that I can think of that you need to pull a shaft just to inspect the bearings.

-- Edited by Marin on Wednesday 10th of November 2010 10:59:43 PM

GonzoF1 wrote:Would you be willing to pay someone over $200/ft. to do that? Would you be willing to do that many, many 100's of times just for cosmetic blisters? If one starts to look evil, I'll tackle it.


Sure... If it were just a few or if I had owned the boat from the start and stayed on top of the effort, maybe. But like I said, blisters don't sink boats, but they'll quickly sink a bank account. It's not that I wouldn't LOVE to have a nice flat bottom, it's just not a good cost versus benefit investment. IMHO

-- Edited by GonzoF1 on Wednesday 10th of November 2010 08:11:26 PM
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I am totally with you on this one Gonzo.* Every time my boat has been antifouled, they comment on it having quite a few small blisters, and we check then, photograph them, and they have never changed from one year to the next over the 8 yrs we've been doing this, so we just sand and antifoul over them and leave well alone.* The fellow who surveyed her noted them and said in all his long years in the business he had never heard of reported or personally knew of any vessel that sank because of a bit of pox, but he knew of many who has spent thousands getting done a job which probably affected the seaworthiness of the vessel not one iota.

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Timjet,
like Marin said they yard I go to will take a look at the bearing holder then give the prop a goog shake side to side and up and down to see if there is some slop. So far they have pronounced them OK. If I remember correctly the surveyor did the same thing when I bought the boat, only about 2500 hours on her now, I believe the bearings last quite a bit longer ( I hope so)
Steve W

timjet wrote:


The engines turn 2750 rpm at WOT and should be turning 2900-3000. Over proping is the #1 reason for early engine failure.*

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According to many articals I have read the first thing you should check before having the props repitched is the back pressure on the exhaust.
This is often the cause for a boat not reaching WOT.

There is also issues such the load and how*clean the bottom is.

If the*props were properly pitched when new.* Why is there an issue now?*

It could be issues other than what you are indicating.
*
I don't knowbut if you have them re pitched and the issue was high back pressure what would the re pitching do to the engine?

Food for thought.

SD













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Gonzo

Blisters sink the resale value of boats. As a prospective buyer, it is common to mark down the offer price by the amount to refinish the hull. Further, as a buyer, I'd also feel that a hull left to its blistering may speak poorly for the owner's attention in other areas. Eric's restorative techniques are neither expensive or time consuming.

Ralph Yost's boat on this forum had a* peel job a few years ago, maybe he could weigh in on the subject.

Two or three years before selling, I did a blister repair on my last sailboat. Same technique as Eric uses. the purchaser's surveyor told me the blisters had been "properly repaired". Cost me one two part pack of cold cure epoxy and a couple of hours work to fix maybe 3 dozen blisters. Each was 1/2 inch to 1.5 inch diameter. some leaked tea when ground into, some didn't.

sunchaser wrote:

Gonzo

Blisters sink the resale value of boats. As a prospective buyer, it is common to mark down the offer price by the amount to refinish the hull. Further, as a buyer, I'd also feel that a hull left to its blistering may speak poorly for the owner's attention in other areas. Eric's restorative techniques are neither expensive or time consuming.

Ralph Yost's boat on this forum had a* peel job a few years ago, maybe he could weigh in on the subject.

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We'll have to agree to disagree then, because a blistered bottom should in no way reflect on the entire boats's upkeep. Like I said... cost vs. benefit. It only sinks the value if you are planning on selling it. If you are going to hold onto it for many years, it's hardly worth it. Sure, a little OCD might drive people to spend that kind of money on it and I won't fault them for it, but you can buy a full electronics suite, a full canvas enclosure, a nice Rolex, or hire a half-dozen young ladies to spend the day naked with you for that kind of layout.

sunchaser wrote:
*hire a half-dozen young ladies to spend the day naked with you for that kind of layout.

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Darn it.
*Now I am gonna be thinking about that all day.

*

skipperdude wrote:

According to many articals I have read the first thing you should check before having the props repitched is the back pressure on the exhaust.
This is often the cause for a boat not reaching WOT.

If the*props were properly pitched when new.* Why is there an issue now?*

I don't knowbut if you have them re pitched and the issue was high back pressure what would the re pitching do to the engine?

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Here's an issue where a little knowledge can be a dangerous thing, but here goes anyway.Many performance boats (planning hulls) from Sea Ray, Carver, Bayliner, etc came from the factory over propped so they would attain the speed advertised. The effect is kinda like running your car in fourth gear all the time, excess engine wear, carbon buildup, etc.
My stbd engine is showing some carbon buildup in the intake side of the turbo and coupled with it's inability to get Cummins specified WOT of 2900-3000 rpm leads me to suspect an over pitch problem. The bottom is clean and probably does not need re-painting since it lives in fresh water for the moment, but I'm re-painting because I'm hauling it. I haven't been able to remove the exhaust side of the turbo because the bolts are rusted in, but it will be removed for inspection before I splash, and I should get a better read on the carbon issue after inspection.
The guru's on boat diesel want me to run it again at WOT to get another read on it, but I don't want to. I don't like putting that much stress on the engines, ever for a short time. So I'm kinda flying blind here by using the sea trial figures which may not be accurate now.
I can think of no down side by easing the pitch on the props other than not getting as much top end speed, which is not important to me. I typically run the boat no higher than 2200 rpm and am fine with the 18 knots that gives me.


The port engine has had the exhaust elbow replaced and inspection shows no carbon build up on the intake side, so I really don't know where I'm at with that engine. I'm also only getting 2750 rpm at WOT. The seller turned hostile and won't give me any information.*

*

sunchaser wrote:

Gonzo

Blisters sink the resale value of boats. As a prospective buyer, it is common to mark down the offer price by the amount to refinish the hull. Further, as a buyer, I'd also feel that a hull left to its blistering may speak poorly for the owner's attention in other areas. Eric's restorative techniques are neither expensive or time consuming.

Ralph Yost's boat on this forum had a* peel job a few years ago, maybe he could weigh in on the subject.

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Mine had HORRIBLE blisters when I bought it. I think we negotiated a $15k reduction in price, then it cost me $25K to properly peel, post-cure, and relaminate. For me, it was worth it. Every time we quick haul the boat I love that nice clean Krogen bottom. The shipyard that did it also comes out to check their work too. We used the HotVac system.

*

timjet wrote:My stbd engine is showing some carbon buildup in the intake side of the turbo and coupled with it's inability to get Cummins specified WOT of 2900-3000 rpm leads me to suspect an over pitch problem.


The port engine has had the exhaust elbow replaced and inspection shows no carbon build up on the intake side,

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All the flags here are waving at an exhaust leak on the STBD engine. Overloading will not magically produce what you call carbon buildup on the compressor.

That stuff is carbon but it is in the form of soot that comes from an exhaust leak, not a carbon deposit as normally describes a specific condition associated with combustion area or exhaust parts. You might get carbon deposits on the turbine but only oily soot on the compressor.

Replacing the exhaust elbow on the port engine seems to have eliminated the exhaust leak and the clean compressor shows it.

As far as another test run, if the engine is not smoking black and the exhaust temperature is not excessive then you won't do any harm. The loss of 150 rpm can be almost anything including tachometer error.


-- Edited by RickB on Friday 12th of November 2010 06:49:24 AM

There are two different WOT one is the manufactures WOT the other is the Maximum Governed WOT. Governed by the fuel pump. It will not allow the engine RPM's to go beyond what will hurt the engine.

So running at WOT will not damage or stress a diesel. If done occasionally. many yards will run at WOT for spring shake down and most Marine Surveys run it up to see if there is a problem i.e. black smoke or not reaching WOT.
It is my understanding that 1 or 2 hundred RPM does not necessarily mean there is a problem.
A diesel engine also performs better under a load does it not?

Many*diesels in heavy equipment are run at WOT continuously. As well as diesel generators.

Please don't take my word on this* but is is something to consider or at least research.*

SD

-- Edited by skipperdude on Friday 12th of November 2010 04:02:13 PM

RickB wrote:

All the flags here are waving at an exhaust leak on the STBD engine. Overloading will not magically produce what you call carbon buildup on the compressor.

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Rick,

How would I know if I had an exhaust leak? I've check the engine at 2000 rpm - no load and have not noted any exhaust leak.

Concerning the port engine and no carbon build-up, As you mentioned and exhaust leak* may have been the issue with it, but it's possible that another problem developed requiring the mixing elbow to be replaced and not enough time has passed for the carbon to build up in it due to over loading ie over pitched prop.

I ran the engine last weekend and got only 2600 rpm out of both of them. During the run I check the vacuum gauges and they were low, not even in the yellow, so lack of fuel should not have caused the low rpm reading. I am going to check the throttle linkage and make sure that full throttle is really selecting full throttle. If that checks out OK, I'm going to have the pitch eased a bit on the props.

At sea trial, the surveyor said the tacks were within 50 rpm.

*

I hauled the boat yesterday and the resident mechanic at the marina suggested that since I have so many small blisters, it would make sense to have the whole bottom sand blasted down to the gel coat. Then it will be easy to see and repair the blisters. Once repaired a barrier coat is applied and then the bottom painted.

I haven't got a price on sand blasting, but the vendor is right next door. I talked to him yesterday and he confirmed it will be a lot easier to see and repair all the blisters once he sand blasted the bottom. He seem like a stand up guy and I trust his opinion. However, if sand blasting is being done just so it's easier to find the blisters, that seems a bit of overkill.

The mechanic that first suggested the sand blasting and application of a barrier coat said that the bottom should last 3 to 4 years without further attention except of course periodic cleaning. Generally in the warm FL waters 2 years is the max you can expect, so if the mechanics opinion is correct, I may come out ahead by doing the sand blasting. I won't know until I get a sand blasting estimate.

Anybody care to comment?

Had the hull soda-blasted back to the gel coat four years ago because there was too much paint build-up.

It certainly, gave a nice even surface to work with and I was able to repair several blisters... but I still get them and simply repair at each haul-out (two-yearly). I wouldn't have the hull blasted simply to provide better access to blisters.

Rather than grind them out, I use a small chisel and cut around and under them, then fill with a vinylester based water-proof filler available from CRC here in NZ.

A quick sand, a couple of coats of Primecon (International) and the surface is ready for antifouling.

Bendit wrote:

Had the hull soda-blasted back to the gel coat four years ago because there was too much paint build-up.



We had the*bottom of our last boat (43')*sand blasted to remove the paint build up on the Gold Coast in OZ in 2003.* Then it cost $1,000.00 (AU).* How much was the soda-blast job in NZ, which the experts say is less destructive to the gel coat?

Larry/Lena
Hobo KK42
La Cruz, Nayarit, MX

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