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AWESOME maintenance write ups. Sea cocks, Thru hulls, etc.

3K views 12 replies 8 participants last post by  xort 
#1 · (Edited)
#3 ·
Maine Sail is one of the most reliable sources of good information on DIY boat repair on the web. He's a member of many sailing forums, including Sailnet and does an amazing job of documenting his work when he has the time. :) Most of us on Sailnet are pretty familiar with his work and his website, but it never hurts to give him a plug... and remind people not aware of it that its there.
 
#4 ·
I'd never hear of this guy before and found the information on his site to very very much in tune with my thinking on just about everything , I guess this makes him brilliant :) . He obviously has a very good understanding of moisture meters but I disagree with his advice to buy one. For the novice I still think a little brass hammer is sufficient to find the really bad stuff.

Most articles on moisture meter are so full of baloney ( including the Electrophysics website) it makes me gag. Here is the artcile from my own site

Moisture Meters


FACT: Moisture meters do not measure moisture.
FACT: Fiberglass is not waterproof.

There are a couple of different types of meters and several brands and detailed discussion would include terms like impedance, dielectric constant, capacitance, resistance and conductance but basically they measure how much electricity a material can store or conduct, so for the purposes of this article we will say they measure something most of us understand.........."conductivity". Of the two basic types of meters, "capacitance" and "resistance" , we will concentrate on the former as resistance type meters have pin sensors ( O.K. for wood, not a great idea for FRP) that must be inserted into the material being tested

A simple analogy would be to suggest that they send out a signal and measure the difference in the sent signal and the return signal, thereby measuring the conductivity of the material (boat surface) between the sending and receiving units. Wet fiber glass or core would be more conductive in theory than dry materials and therefore show a higher reading on the meter.

There are many things that can confuse a moisture meter and considerable experience is required to make proper use of them. Given that they actually measure capacitance rather than moisture, highly conductive materials will show higher readings on the meter whether or not they are wet.

The "Code of Practice for the Measurement and Analysis of the Wetness of FRP Hulls" ( * International Institute of Marine Surveyors (1998) Witherby & Co., London, 17p. ) specifies the methods necessary. These include: The surface must be carefully cleaned. A large number of random 4" x 4" areas must have paint or other coating removed down to the gel coat. The vessel should be out of the water at least 24 hours. Minimum number of measurements must be = approx. one per sq. meter (3.3 feet) or 50-100 on the average 35-40 foot boat. Few sellers will allow bottom paint to be scraped as necessary for an accurate determination.

Generally buyers are also not willing to pay the costs necessary for the yard to first block the boat and scrape the paint, then re-coat after analysis. If there are reasons to suspect a serious moisture problem, such as water intrusion in a cored hull, you may have to take core samples to be 100% sure of the condition.

Some examples of meter confusion.........


if your boats gelcoat contains a lot of titanium dioxide (a common white pigment made of metal) the meter may read high depending on the pigment concentration.

if the non-skid on your deck is very deeply moulded or if the non-skid paint is very rough, meter contact may be limited so that a false low reading is shown on the meter. Some non-skid paints are rubber based and as this is an insulator again false low readings may show.

if you place a meter on the outside of a hull and there are metal fittings, anchor chain, water hoses or fuel tanks in contact with the inside, the meter may read high.

if a large saturated blister is deep in the laminate the meter may show "dry" as the moisture is too deep for the weak signal of the meter to penetrate the laminate.

if water saturated core has separated from the FRP skin, the meter may read "dry" as there is no contact for conductivity.

if your bottom is epoxy coated, the meter may read low depending on the insulating properties of the epoxy.

if the core is frozen: A number of years ago I did a lot of testing with frozen blocks of bits of decks and hulls and was convinced that I could determine moisture content of frozen core ..... I was wrong ! What worked in the kitchen did not work in the field. In the kitchen at ambient temperature the meter was warm enough to create a thin film of moisture on the frozen bit and register on the meter. Outside in below freezing temperatures this did not occur.
When water freezes it expands by about 8%, The crystalization that causes the expansion results in a lot of non-conductive space within the water thereby greatly reducing the effectiveness of the meter. When meters are unreliable we can use the percussive sounding method, unfortunately this too goes out the window because frozen core whether balsa or plywood sounds solid. I need the work as I don't have much in the winter months and will survey a frozen boat (balsa cored hulls excepted) as long as you are willing to live with the limitations. My best advice .... wait til' spring.

As they send out a very weak signal, these meters do not read reliably much more than 1/4" deep and not more than 1/8" deep on some laminate schedules although some manufacturers claim up to 1" ( not sure I buy this!). Many unnecessary epoxy bottom jobs are initiated by the improper use of moisture meters and many more of these jobs fail for the same reason.

Remembering that the meter is actually measuring the conductivity (or capacitance) of the material, we must also consider that the fiber/resin ratio, whether chopped strand, roving or mat and different types of resins will all have an affect on conductivity. Also remember that bottom, topsides, decks and superstructure of the same boat will often have different laminate schedules and construction techniques all of which again affect conductivity.

The average 30' uncored hull can absorb a maximum of about 3% water as contrary to popular beliefs, polyester resin is hygroscopic. For a 30' uncored boat this is somewhere between 20 and 30lbs. and it can take months to dry out ... if ever. The only way to accurately measure moisture content is to cut a piece from the hull, weigh it, bake it for a couple of weeks or burn it, weigh it again and measure the difference.

These meters can give an indication of relative moisture content or at least point out anomalies across a given area but this is just the beginning. Once anomalies have been identified we must confirm the reasons by examining the inside surface of that area for causes other than moisture or perhaps removing an area of bottom paint and re-testing.
It should be remembered that proving a 6" X 6" area wet or dry does exactly that and only that !

Assuming the same substrate (the layup is likely different in several areas of the bottom), these meters can show different levels of moisture across a given area. This can be useful if the bottom has been stripped of gelcoat and we are trying to determine if it is dry enough to to accept an epoxy barrier coat. If the meter reads XXXX when the hull is first stripped and XX two months later then moisture content has been reduced. If after another two months the meter still reads XX it does not mean the hull is not dry, just as dry as it's going to get. Whatever the reading, it is relative and does not actually show 5% or 30% water content or whatever other number the meter generates.

Moisture content is NOT a predictor of blisters and don't let anyone tell you different. While blisters without moisture are highly unlikely, thousands of boats out there have had high moisture levels for decades without a blister in sight.

I use the meter in my left hand and a hammer in my right. I use it as a backup and second guess and yes I make mention of the readings in my survey reports but only because so many people ask for them. I don't personally believe they are of much value on the bottom of a boat unless the previously mentioned "Code of Practice" is followed and even then it's only going to tell you what we already know.....boat bottoms are wet !

There are several places now advertising these meters to the general boating public suggesting they are cheaper than hiring a surveyor. Don't waste your money, even an untrained ear can detect soft balsa core under FRP in most cases. Invest about $9.00 in small brass hammer instead.

I am often surprised by the ignorance of many marine surveyors regarding these issues. Even the hammer is not infallible, if the laminate is thicker than usual or wet core has separated from a thicker than usual FRP laminate or even how the boat is blocked or supported may affect percussive soundings. What we are really dealing with is an educated guess. Sometimes there is just no way around taking a core sample but the meter should never be used as the sole arbiter.

Cored hulls are different animals all together and one day I will post my opinions on cored hulls vs. moisture meters.
 
#5 ·
I'm not surprised that you don't like seeing someone recommend buying a moisture meter-most surveyors don't. I don't think Maine Sail has ever advocated using a moisture meter as the sole arbiter. Like I say in my boat inspection trips tips post, there are many things to consider, when evaluating a boat as a possible purchase.

The idea isn't to replace a professional survey, but to eliminate boats that aren't worthy of getting a survey for in the first place, and saving the money that would have been spent on a survey. Once you understand the limitations of a moisture meter, it is a very useful tool, and one that is relatively easy to learn to use. It isn't rocket science.
 
#6 ·
I agree, it ain't rocket science I'm just suggesting that $200.00 could be saved if $9.00 was spent on a small brass hammer instead. A small hammer and a little practice will find 90% of the stuff a meter will find and you don't have to second guess yourself when you hit strange readings.

A little forethought and your inspection tips can save a lot of money and a lot of needless surveys. That is why I have so many articles about maintenance, boat buying tips and sample surveys on my website.
 
#7 · (Edited)
Yes, but many boat owners will let you run a moisture meter on their boats, when they'd be hesistant to give you free run with a hammer all over their boat.
 
#8 · (Edited)
Wow

Thanks Moonie!

I do this because about ten years ago, jeeze maybe 12 now, I helped a guy in my boat yard fix what I considered a relatively simple and benign issue. It seemed so basic and simple to me but not to him and I had a hard time understanding it. He even had a couple of "marine books" there to help him but still he was having difficulty.

The passion this guy exuded for the sport was infatuating but sadly his wallet could not keep up with the yard bills. When I saw him last he was cleaning his personal effects off his boat and clearly very depressed. His comment to me was that he could not keep up with the repair bills and had to sell the boat.

At that point I decided I would try to find a way to share my skills and make it as easy to understand as possible seeing as the books did not help him much. It has been a lot of trial and error and I still constantly try to make my articles more precise and in-depth and simplified so that even those not mechanically inclined are willing to give it a try.

I hate to see anyone be priced out of a sport they love because they feel they can't do simple projects that would be the difference between sell or keep the boat.. It is my belief that sailing still can be a middle class sport but much of the maintenance work needs now to be undertaken by the owner and not the yard.

If I can save even one boater some money that he could put into savings or into his boat in the form of an upgrade, as opposed to a repair, my mission is working as I intended..

I have lots more to publish but time is my enemy. Sadly for the site, but not so sadly for me, I do have a real job a two year old, a wife and a boat to help divide my time.


One of my biggest issues is that photographing each step of the project takes time and adds time to the project itself. I need to clean my hands every time I pick up my camera and use it, so I often just fix something and don't photograph it, though I am trying to be better about this.

As an example I have the beginning & end photos of installing a Harken MK IV roller furler but once the Loctite and 4200 came out the camera was put away so I have no middle photos to complete a "how to".

Unfortunately I have many "partial" articles that are missing photos.. Winter time usually sees a few new additions to the site and the occasional one in the summer. I should have "replacing a rear main engine seal" done soon...

Again I really appreciate the kind words and support and will keep it up as time allows! The wood stove is on in the barn as we speak so I can work on more boat projects this weekend...

As for the moisture meter I respectfully disagree with BoatPoker but his response is not surprising.

I use it for a lot more than just buying boats and I do use it on my own boat about once or twice per year. My own boat is a prime example of where a hammer would not have sufficed. She spent some time in the carib heat and as such has a few areas of DRY deck delamination of the top skin. With my hammer it sounded wet and like the typical soggy core or delam would. It was not until I pulled out my meter that I could confirm it to be dry delam. I then did a core sample to confirm my findings and they were spot on and dry as a bone.

Had I only been using a hammer there is a good chance I could have walked away from a boat that needed a rather simple repair vs. one I incorrectly thought to be a major wet one.

I also state quite boldly that a DIY using a moisture meter is only to rule out potential basket cases when used appropriately and that it DOES NOT relpace a competent survey. When buying my current boat I looked at over 50 vessels. Of those 50 nearly 60% had massive amounts of moisture in the deck core. On perhaps 20% you did not need either a hammer or a meter as the brown coffee like goo representing rotting core was dripping from every interior screw hole in the cabin..

Yes I can tell a lot with my phenolic hammer, nearly as much as with my meter, but as a boat owner myself I'd much prefer to see a potential buyer using a meter than a hammer on my AwlGriped finish. Plus no matter how much you tell someone to use a brass or phenolic hammer they will still use an iron hammer and destroy your finish.;)

It is up to each boat owner to decide if the cost of a moisture meter is worth it and if they are willing to put the time in to actually learn how to use it. Most won't so BoatPoker has plenty of job security. Those who are willing to lay out the money for a meter are generally the ones who will do the research and take the time to learn how to use it to the best of their ability.

Hell when I worked in boat yards some of the fiberglass repair guys had no clue how to use one yet they used it to to decide how much deck to tear up and replace....:confused::confused::confused: Guess what the boat owner usually paid WAY to much for the repair than they needed...:eek:
 
#10 ·
...One of my biggest issues is that photographing each step of the project takes time and adds time to the project itself. I need to clean my hands every time I pick up my camera and use it, so I often just fix something and don't photograph it, though I am trying to be better about this...
Maine Sail,

I'd gladly hold the camera if you want to come down to Long Island and help with my boat.

Then again, I'm sure you hear that a lot.

Regards
 
#13 ·
Mr. Obvious here...never thought of having a moisture meter to continously monitor the boat over time. Now I have to go buy a meter!!
I better not find any wet core or mainesail is going to have to come and repair it!! Ignorance is bliss.

I volunteered to do the photography first!! And I'm a pro too, we'll sleep in the barn and shoot for food!
 
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