Bottom Cleaning

[CPseudonym]

I realize the answer to this question is regional/geographic in nature to some extent. Although my region of operation will be predominately the SF Bay and Delta, I am interested in hearing responses from all geographic areas including our friends in Oz.

How often do you dive on your boat(or have it dove on for you) to clean and inspect the bottom?

I am interested in what the norm is for you and others in your respective locales. This subject has had my curiosity for some time now.

 

[dwhatty]

Only dive when we have wrapped a pot warp. Boat gets hauled every fall.


-- Edited by dwhatty on Tuesday 27th of March 2012 05:48:30 AM

 

[rwidman]

Once a month to six weeks in cold weather, as often as every thee weeks in hot weather.

*

That would be in Charleston, SC, USA.


-- Edited by rwidman on Tuesday 27th of March 2012 06:10:00 AM

 

[Larry M]

We clean the bottom a least monthly based on how fertile the waters are.* The prop and SS rudder usually need the attention first.* We have an electric hookah with 60' of airline and the 80 degree water makes it easier.* The heavy growth started once we got into the Pacific Coast of Mexico.*

 

[Steppen]

In northern portion of Puget Sound we have the bottom cleaned and inspected by a diver every 3 to 4 months (cost is about $70/dive without any zinc replacements).* Haul out and repaint bottom every two years on average.

 

[Phil Fill]

In Everett Washington, have a diver every 6 months, and pull every 3 years.* Everett marina is at the mouth of the Snohomish River so the water is brackish, first 2 to 3 ft is fresh water.* So the deep keel boats get the growth, mostly on the prop, running gear and through hulls.* Most of the growth is during the warmer sunny summer months.* During the cold cloudy winter months with the muddy/cloudy water not much growth.
*

Many of the boats use the Pettit Trinidad hard epoxy with high copper content.* They are banning high copper bottom paint in the Puget Sound, 2014, so we will pull just before and in the future have to go up to Canada.

 

[Art]

CPseudonym wrote:
I realize the answer to this question is regional/geographic in nature to some extent. Although my region of operation will be predominately the SF Bay and Delta, I am interested in hearing responses from all geographic areas including our friends in Oz.

How often do you dive on your boat(or have it dove on for you) to clean and inspect the bottom?

I am interested in what the norm is for you and others in your respective locales. This subject has had my curiosity for some time now.

*Ahoy Craig!
*
This might be a bit more than you ask for... but your request regarding SF Bay Area waters that I ply simply got me going... hope the following helps!* Happy continued safe and affordable boating.* Regarding boat bottoms and running apparatus/metals: Ounces of prevention can truly be worth pounds of cure!* Cheers!! Art
*
When I have a boat that sits idle in any SF Bay sal****er harbor... I dive or pay a diver to clean bottom and apparatus every six months.* If I take our Tolly regularly on cruises, due to its plaining capabilities at 16/17 knot cruise (only need to keep it at that speed for 20 minutes, then I drop back to trawler speed), the bottom cleaning can be well delayed due to self-scrubbing from water friction.* Usually dive for zinc changes in nine months to a year, depending on stray-current severity of a harbors electrics.
*
While sitting idle in any SF Deltas freshwater harbor, or while gentle cruising/hooking in the Delta... Due to comparatively warm water, where bathing suit diving is a joy, I happily go under boat whenever were there during spring, summer, fall and yearly enjoy 13 to 18 long, sunny weekends out and about on our Tolly in the Delta (were 100 miles house to boat).* In Delta there is little to no growth that develops on hull.* Apparatus is simple to brush off with a swipe or two of a fairly course hand held scrub-pad.* In winter we go up once in a while to look things over and go out if it is real nice weather, maybe stay a night; in winter I do not go under boat for five to six months straight.* That said the next items are important regarding sal****er and freshwater anode use and maintenance, as well as stray-electricity/electrolysis protection and minimization.
*
Anodes (These are my recommendations only I suggest you do through research.* Anode protection is very important to understand.* It can save or cost you much time and $$$):
*
Sal****er anodes Zinc only!* Change as required.* Some sal****er harbors are stray-electric cool, wherein zincs may last for year or longer... but, in electrically hot harbors zinc may degrade to useless in short months.* Keep your eyes open!
*
Freshwater anodes Magnesium or Zinc! (I do not recommend aluminum your research should reveal more on this and other anode factors)
*
1.**** Magnesium: Mag degrades faster than zinc, costs more, and to me it seems harder to locate correctly fitting pieces.* But, mag anodes do a good job for protecting your metals as they degrade (flake-off) fast enough so they dont develop surface buildup; such as buildup that can occur if let to progress too far on zincs, and that can then hinder zinc-anode protection qualities.
2.**** Zinc (my personal favorite for salt or fresh waters): Zinc degrades rather slowly in fresh water compared to mag (Ive found it to be approx one year for mag; three years for zinc).* In so doing, especially when a boat is kept in an electrically cool location and manner of docking the zinc can develop water-born surface buildup, a thin skim/skin of freshwater-growths on its outermost surfaces.* This skim deters zincs less noble metal from attracting stray electric currents and that can affect the rate of corrosion that may occur to other metal parts via the stray currents.* The skim on zinc surface will occur at different rates depending on stray-electric intensity in, on, or around the boat (electrically hotter dock/boat = less skim / cooler = more skim; due to oxidation flake-off rates on the surface area of zinc).* So... it is best to bronze wire brush clean (BBQ grill cleaning brush works great) the surfaces of zinc anodes at least once every six months... during shorter durations if possible.
*
My recommendations for keeping any boat free as possible from stray electric current, in fresh or salt waters:
*
a.**** Make certain your hulls fittings, fixtures, and its overall condition, as well as the boats entire decks and superstructure, allow NO water intrusion of any sort that can enter the bilge.* None Period!
b.**** Have fully charged and good condition bank of batteries on board that are hooked to self actuating bilge pump(s)... just in case there were any minor water intrusion into the bilge while you were away.
c.***** Off connect AC power cable at the dock-box and the on-board receptacle.* Do not let any portion of cable drape in water whether it is activated or not.
d.**** Be sure that all on board DC master switches and all breakers are in off position (making sure that auto bilge pumps are direct wired to battery bank and will activate even with all switches off)
e.**** Be sure the boat is affixed to the dock with fabric lines only and that there are no metal lines hooked from boat to dock.
*
I have learned that this boat-isolation method notably reduces stray-currents from docks or other near-by craft affecting my boats running gear and/or anodes.* Of course, due to sal****ers considerable elevated electrical conductivity as compared to freshwaters limited conductivity... there is in general less chance of corrosion/oxidation/electrolysis in fresh water settings.
*
Couple of in-depth, interesting corrosion reviews by David Pascoe (web search has other interesting anode accountings):
*
http://www.yachtsurvey.com/corrosion.htm and http://www.yachtsurvey.com/corrosion_in_marinas.htm
*
PS: Depending on paint brand/type and application quality, new bottom paint is usually needed two to four years in SF Bay / four to six years... or sometimes even longer in SF Delta

*

 

[fstbttms]

OK, I'm the new guy here, but there are some inaccuracies in the post above that I feel the need to address and I'm not going to pull any punches. Let me start off by mentioning that I earn my living cleaning boat bottoms in the SF East Bay Area and my comments are (for the most part) directed at Bay Area boaters keeping their boats in salt water marinas. So take that for what it's worth while reading my post.

1.- Service frequency. Cleaning every 6 months or less is inadequate. I guarantee the hull is getting foul to the point that boat performance is negatively affected, within that length of time, regardless of what anti fouling product you have on the bottom. Boat speed is reduced and fuel consumption and carbon emissions are increased. More importantly, by letting your hull get as foul as it undoubtedly is at 6 months, your hull cleaner will be unable to use the softest cleaning media to remove the fouling growth. He will be forced to use an abrasive scrubber or brush or maybe even a scraper to clean your hull. This means he is removing paint and shortening your expensive anti fouling's lifespan. The heart of any in-water hull cleaning Best Management Practice is to always clean the hull with the softest implement possible. This is only possible if the hull is not allowed to become even moderately foul. Relatively frequent, gentle cleanings can extend the time between haulouts for paint as opposed to less frequent, more abrasive cleanings. By as much as a year or more. Ideally (in the Bay Area) you should have your bottom cleaned 4-6 times per year.

2.- Zinc anodes should not be used in freshwater. They are not designed to be used in freshwater and will not provide the protection against corrosion you need. Zinc anodes are for use in salt water only. The reason Art finds his zinc anodes lasting a long time in freshwater is because they are not working in freshwater! Magnesium anodes are designed to be used in freshwater. They should not be used in salt water. Aluminum anodes are designed to be used in salt or freshwater. And despite Art's recommendation against aluminum anodes, more and more boat builders and engine manufacturers are requiring them on their products.

3.- Popular and commonly used anti fouling paints will last from 2-3 years, regardless of where you are in a salt water environment in California. Biocide leach rates and maintenance techniques dictate this. You may still have have paint on the hull at 4 years or more, but it is not doing its job properly. It can't. The copper (or increasingly, zinc) has leached out. That's just the nature of the beast.



-- Edited by fstbttms on Wednesday 28th of March 2012 09:21:14 AM


-- Edited by fstbttms on Wednesday 28th of March 2012 09:22:04 AM

 

[Art]

fstbttms wrote:
OK, I'm the new guy here, but there are some inaccuracies in the post above that I feel the need to address and I'm not going to pull any punches. Let me start off by mentioning that I earn my living cleaning boat bottoms in the SF East Bay Area and my comments are (for the most part) directed at Bay Area boaters keeping their boats in salt water marinas. So take that for what it's worth while reading my post.

1.- Service frequency. Cleaning every 6 months or less is inadequate. I guarantee the hull is getting foul to the point that boat performance is negatively affected, within that length of time, regardless of what anti fouling product you have on the bottom. Boat speed is reduced and fuel consumption and carbon emissions are increased. More importantly, by letting your hull get as foul as it undoubtedly is at 6 months, your hull cleaner will be unable to use the softest cleaning media to remove the fouling growth. He will be forced to use an abrasive scrubber or brush or maybe even a scraper to clean your hull. This means he is removing paint and shortening your expensive anti fouling's lifespan. The heart of any in-water hull cleaning Best Management Practice is to always clean the hull with the softest implement possible. This is only possible if the hull is not allowed to become even moderately foul. Relatively frequent, gentle cleanings can extend the time between haulouts for paint as opposed to less frequent, more abrasive cleanings. By as much as a year or more. Ideally (in the Bay Area) you should have your bottom cleaned 4-6 times per year.

2.- Zinc anodes should not be used in freshwater. They are not designed to be used in freshwater and will not provide the protection against corrosion you need. Zinc anodes are for use in salt water only. The reason Art finds his zinc anodes lasting a long time in freshwater is because they are not working in freshwater! Magnesium anodes are designed to be used in freshwater. They should not be used in salt water. Aluminum anodes are designed to be used in salt or freshwater. And despite Art's recommendation against aluminum anodes, more and more boat builders and engine manufacturers are requiring them on their products.

3.- Popular and commonly used anti fouling paints will last from 2-3 years, regardless of where you are in a salt water environment in California. Biocide leach rates and maintenance techniques dictate this. You may still have have paint on the hull at 4 years or more, but it is not doing its job properly. It can't. The copper (or increasingly, zinc) has leached out. That's just the nature of the beast.

Hello Matt
*
With you as a diver, I can see most of your intent.* You sound as though you probably do a good job of boat-bottom cleaning; and, I have no disagreement with it being a good practice to often as possible clean boat-bottoms using a soft brush... that said... from decades of owning and working on commercial and pleasure boats, as well as many past years having worked in New England boat yards, there are none I've seen in harbors that have bottom fully scrapped-clean by a diver every two months.* If I may say so, in salt water a cleaning every month would be nice too... but, that just doesnt happen in reality for any but maybe the very rich.
*
Regarding your statement about zinc in fresh water: If you read my post carefully, I clearly mention that when using zinc in fresh water it must have its surface often bronze wire brushed clean of any fresh water sediment that becomes attached in order to reveal the less noble zinc service.* Ive spoken with anode material design specialists, i.e. metallurgy scientists and engineers over the years who assure me that zinc is a fine anode in fresh water as long as its surface is often cleaned.* That said if a boater does not often clean the zinc surface then the zinc anodic qualities will progressively decrease to the point of eventual failure.* I clean my own zinc and change them when required (at approx 25% remainder).* There has been no corrosion on my boats running gear.*
*
Welcome to this Forum!**

*


-- Edited by Art on Wednesday 28th of March 2012 10:40:08 AM

 

[Pineapple Girl]

interesting info Art and fastbottoms.* We are also on the SF Bay and the diver checks the boat quarterly and cleans the bottom / replaces zincs if needed.* We were in the delta July and August last year and ended up only getting the bottom cleaned*I think twice last year as between using it a lot and the two months in "fresh" (brackish?) water we didn't have much growth. *We just had the bottom painted and new zincs installed in February.*

Fast bottoms in light of your comments on zincs, sounds like I need to have all my zincs taken off and replaced with magnesium or aluminum while my boat is in the delta for April-October this year???*

*

 

[Art]

Pineapple Girl wrote:
interesting info Art and fastbottoms.* We are also on the SF Bay and the diver checks the boat quarterly and cleans the bottom / replaces zincs if needed.* We were in the delta July and August last year and ended up only getting the bottom cleaned*I think twice last year as between using it a lot and the two months in "fresh" (brackish?) water we didn't have much growth. *We just had the bottom painted and new zincs installed in February.*

Fast bottoms in light of your comments on zincs, sounds like I need to have all my zincs taken off and replaced with magnesium or aluminum while my boat is in the delta for April-October this year???**

Hi Jennifer*

Or, you could simply enjoy going under boat with mask, fins and bronze BBQ brush to quickly/simply*scrub zinc surfaces... at least*that is my opinion.

I*look forward to learn fastbottom input on your question.

BTW - Hope to see you in Delta this season.* No doubt we will be up several times and for a long weekend*on*4th July near certain!* Currrently we are daily expecting our 4th grand child (3rd Gurl!) and, can see it will be a while before we leave town for a long*Delta*weekend: much family ta-do going on!* New baby may have been conceived last Fourth O' July in Delta on our Tolly, while Linda and*I were out in the*runabout visiting friends*and da kids stayed aboard!!* Now, that's a fun*kick!*

Cheers! - Art

 

[fstbttms]

@Art- your experience notwithstanding (mine, BTW, is 17+ years in the biz and well over 20,000 hull cleanings performed), 2-month cleaning frequencies are common here in the Bay Area (admittedly more so amongst sailors than powerboat owners) and proper hull cleaning frequencies are not the purvue of the "very rich" as you claim. In fact, by cleaning more frequently and extending the time between haulouts the boat owner can save thousands of dollars over the long run. It is actually cheaper to keep your hull clean than it is to neglect it.

Regarding zinc anodes in freshwater- I challenge you to provide something, anything, substantiating your position. Here's my substantiation:

From the Martyr Anodes web site:
* Zinc Alloy (US Mil-A-18001K): For Salt Water Only
** Aluminum Alloy (US MIL-A-24779(SH): For Salt & Brackish Water Only
*** Magnesium Alloy (AZ91D): For Fresh Water Only

Dont be fooled by claims that only one alloy will protect in all water environments.*

www.martyranodes.com

And my intent here is simply to impart accurate information to the boating community. You will never see me promoting my business on this, or any of the many boating forums that I frequent.

@Pineapple Girl- if you are only going to be in freshwater for a short period, it's probably not really necessary to swap out anodes. But that being said, I wouldn't assume that there is no reason to check them while in a freshwater environment.

 

[RT Firefly]

Greetings,
Firstly, apologies for hijacking the bottom cleaning aspect of this thread. The boat I am tending is in water that can be salty, brackish or fresh depending on rainfall. Can one mix sacrificial anodes? (I don't think so but just asking). What would be recommended for my use? Can I keep the zinc anodes on and hang a piece of magnesium or aluminum over the side connected to my grounding system? (Could be making a battery here). Now I'm REALLY confused! Lastly, where can I purchase aluminum anodes in the syle I require-meaning are all zinc profiles of anodes available in the same shapes in aluminum?


-- Edited by RT Firefly on Wednesday 28th of March 2012 12:34:43 PM

 

[psneeld]

From boat zincs.com

*


The hard scale commonly found on the surface of zinc anodes is Zinc Carbonate (ZnCO3). Carbonate (CO3) occurs in all bodies of water and originates from atmospheric carbon dioxide gas (CO2) naturally dissolving into the water. In general you do not need to be concerned about this scale as it only affects the maximum output amperage of the anode, not the anodes required trickle output necessary to maintain effective corrosion protection. Zinc Carbonate is water insoluble, but can be readily removed by either alkalies or acids.

 

[fstbttms]

@RT Firefly- do not mix anodes. You probably should be using aluminum, since your boat lives in a variety of water flavors and aluminum works in all of them.

 

[Art]

fstbttms wrote:
@Art- your experience notwithstanding (mine, BTW, is 17+ years in the biz and well over 20,000 hull cleanings performed), 2-month cleaning frequencies are common here in the Bay Area (admittedly more so amongst sailors than powerboat owners) and proper hull cleaning frequencies are not the purvue of the "very rich" as you claim. In fact, by cleaning more frequently and extending the time between haulouts the boat owner can save thousands of dollars over the long run. It is actually cheaper to keep your hull clean than it is to neglect it. Regarding zinc anodes in freshwater- I challenge you to provide something, anything, substantiating your position. Here's my substantiation: From the Martyr Anodes web site: * Zinc Alloy (US Mil-A-18001K): For Salt Water Only ** Aluminum Alloy (US MIL-A-24779(SH): For Salt & Brackish Water Only *** Magnesium Alloy (AZ91D): For Fresh Water Only Dont be fooled by claims that only one alloy will protect in all water environments.* www.martyranodes.com And my intent here is simply to impart accurate information to the boating community. You will never see me promoting my business on this, or any of the many boating forums that I frequent. @Pineapple Girl- if you are only going to be in freshwater for a short period, it's probably not really necessary to swap out anodes. But that being said, I wouldn't assume that there is no reason to check them while in a freshwater environment.

Fstbttms
*
Following are full sentence quotes from Martyr Anodes website you linked in previous post. *Page link: http://www.martyranodes.com/content/martyr-resources/about-corrosion.php See quotes below.
*
Pertinent sentence areas I highlighted are excerpted here, i.e. ... for example the surface of a zinc... if left in fresh water for some time become covered with an off white crust of oxide which effectively seals the anode and stops it working... It is therefore very important to check Zinc... [in] fresh water and if necessary clean [it] off...* Which is exactly what I say and recommend in my first post.* Often self-performing my zinc cleaning as an ongoing sequence to the surface of zinc for it to continue working unabated by surface coating in fresh water.* Therefore, as I say and do... if properly tended, Zinc can function as an applicable anode in fresh water.* If left unattended zinc will eventually cease functioning as an anode.
*
Art
*
*
Not all anodes are suitable for every environment, for example the surface of a zinc or aluminum anode will if left in fresh water for some time become covered with an off white crust of oxide which effectively seals the anode and stops it working even when returned to salt water. Zinc Anodes suffer a similar problem even in brackish conditions whereas Aluminum will continue to operate effectively in river estuaries and other areas of brackish water indefinitely. The consequences of this passivity of the anode are that the next most anodic item within the anode bonding system will start to sacrifice itself which could of course be very serious.
It is therefore very important to check Zinc and Aluminum anodes after any trips into fresh water and if necessary clean off or change the anodes. Should a vessel move into fresh water for more than two weeks Martyr recommends that an alternative anode system is used suitable for fresh water situations.

*


-- Edited by Art on Wednesday 28th of March 2012 01:30:38 PM

 

[Art]

fstbttms wrote:
@Art- your experience notwithstanding (mine, BTW, is 17+ years in the biz and well over 20,000 hull cleanings performed

Interesting "personal" experience count*you present, i.e. "mine, BTW, is 17+ years in the biz and well over 20,000 hull cleanings performed."

By The Numbers:

Over 20K cleanings in 17 + yrs = approx 1,176 hull cleanings per yr.

Which = 22.6 per every week of every year for 17 yrs - Non Stop!

Which = 3.2 per every day*of every year for 17 yrs - With Not One Day*Off!

You are industerious; your words "mine, BTW"*make it sound as though you accomplished that yourself...?

 

[RT Firefly]

Greetings,
Aw c'mon Mr. Art, let's just say Mr. fstbttms has a lot of experience. I, for one, welcome him and look forward to his current and future contributions.

 

[Art]

RT Firefly wrote:
Greetings,
Aw c'mon Mr. Art, let's just say Mr. fstbttms has a lot of experience. I, for one, welcome him and look forward to his current and future contributions.

Aw, Gosh RT... At Your Request, and For You, OK... Ill Back Off!*
*
However, if attacked and severely contested/countered*on a premise I know from experience to be absolutely correct, as well as one that is potentially troublesome to fellow boaters piece of mind, and to have blatantly be told in no uncertain words to substantiate my premise... I usually do not sit idle for long... that is simply the nature of my beast!
*
Cheers! Art**

*

 

[CPseudonym]

I do not know fstbttms but have seen him post in other forums. He seems to post from a position of experience and I have never seen him solicit business directly or indirectly in any of his posts. I say welcome aboard.

Anode recommendations are interesting though I am still interested in cleaning and inspection frequencies of other members in different locales. Anyone find any interesting sea critters under there yet?

Thank you to all who have responded thus far.

 

[fstbttms]

Art,
I dont know what you consider a full work day, but in the hull cleaning business, doing 8 boats a day is pretty typical. Any hull cleaner will confirm this. I have done as many as 20 in a day. So yes, 20,000 service events in a 17-year stretch is not unreasonable. I understand that you may consider yourself something of an expert on the subject. You're not of course, but maybe you should consider becoming one before you cast aspersions at someone who is.

 

[fstbttms]

@CP- I once saw two California spiny lobsters in widely separated slips in a marina on the Estuary. Never seen any before or since. Weird, since spiny lobsters are not indigenous to Nor Cal.

 

[Art]

fstbttms wrote:
Art, I dont know what you consider a full work day, but in the hull cleaning business, doing 8 boats a day is pretty typical. Any hull cleaner will confirm this. I have done as many as 20 in a day. So yes, 20,000 service events in a 17-year stretch is not unreasonable. I understand that you may consider yourself something of an expert on the subject. You're not of course, but maybe you should consider becoming one before you cast aspersions at someone who is.

Dear FB
*
You today came in this forum, on this thread, diametrically contradicting my decades of knowledge regarding zinc as an OK fresh water anode as long as it is often wire brushed clean on its surface.* You clearly implied I was completely incorrect!* Regarding which you have not even again mentioned since I provided the proof you requested that I am correct... straight from the Anode website that you recommended. *For you to not know or understand the quotes I supplied regarding zinc in fresh water, from your recommended website, leaves me suspect... *
*
I have dived under boats for cleaning and other performances much of*my life... still do.* I well understand length of time to correctly clean a hull and all its apparatus.* 20 in an 8 hour day, as you say...*
*

*

 

[fstbttms]

Here's why I can clean 8 boats a day without much trouble and you clearly struggle cleaning one- I don't let my client's boats sit and get foul for 6 months at a stretch, so they clean up easily and relatively quickly. Around here we call it "proper boat maintenance." You oughta try it some time. ;-)

 

[RT Firefly]

Greetings,
Aw Jeez guys, give it a break until Sunday, say. OTDE should be back in action at that time and you can trade fart intensities and frequencies at that time. I'm sure you BOTH have something valuable to contribute without getting into a pissing contest at this point. One guy cleans bottoms the other is a chemist (I think). All that was asked is the frequency of bottom cleaning NOT wiping in various cruising areas ! OK, the thread morphed (as is usual and expected) into anodal protection but MY Question is "Who has smelt REALLY bad cheese?" C'mon, 'fess up.....Mr. Art, not asking for any favoritism here, just chill mon.....

 

[fstbttms]

I'm liking this forum. Good fun from Day One!

 

[RT Firefly]

Greetings Mr. bttms.....it gets better!!!!! Hahahaha....

 

[fstbttms]

I dunno, it's been pretty good already! I like mixing it up and so far, no shortage of that here.

 

[psneeld]

Doesn't really matter what is being discussed about zinc..unless you put a meter on*your underwater fittings*and check*them regularly...you have no idea whether it's protecting your underwater metal or not.

 

[rwidman]

psneeld wrote:
Doesn't really matter what is being discussed about zinc..unless you put a meter on*your underwater fittings*and check*them regularly...you have no idea whether it's protecting your underwater metal or not.

If they are being disolved, they are working.

*