Albin Hull

[Ron222]

As a former A27 owner and current A34 owner it surprised me to find out that the A34 hull is balsa core below the water line. I am pretty sure the A27 was solid (and I mean solid) thick fiberglass top to bottom. Because of accumulating water in the bilge last year and our process of elimination I asked the boat yard to rebed the rudder last week. When they pulled the bolts holding the rudder support water came running out of the balsa core. After dropping the rudder we could feel the soft balsa. According to a moisture meter the area with high moisture extends is at least 2-3 ft in circumference including the strut supports. I have to tell you this came as a big surprise to the boatyard and me. They asked...what was Albin thinking when they used balsa cored fiberglass under the water line to hold the rudder and struts!!?? Now, the fiberglass shell is fairly thick but still don't other balsa core boats have only the hull above the water line with balsa to reduce weight and not extend the coring below the water. This seems like a bad design and makes me disappointed in Albin. This may be the reason so few A34's were built. Am I the only one surprised by this discovery?
Ron
A34 Paumanok

[jleonard]

Many boats (Fortier, Duffy (some)), have balsa cored hulls.
"Sandwhich construction" is strong and light, however it has it's obvious disadvantages below the water line.
They take a very long time to dry out once they are wet.

[DougSea]

Hi Ron,

I'm not the least bi surprised about the coring, all of the early 28TE's are balsa cores (no one seems to have the deffinative answer on when they switched to synthetic) to provide strength and stiffness with light weight. Your A27, as a displacement boat, could carry the weight of a solid hull.

What does surprise me is what sounds like improper installation of a major thru hull fitting. Proper installation involves cutting an oversized hole through the inner skin and core, , filling it with epoxy, and then drilling out for the fitting. This does several things; seals the core against water infiltration, prevents crush damage from tightening the nuts on fittings, and in some cases, gives a better mount point for bolts and screws used to set larger fittings. Hope that a rudder installer missed some checklist items! You should probably have the area around your other underwater the hulls checked with a moisture meter.

[RicM]

A lot of Albin boats were made with balsa coring before 2000. Discussions about coring issues have been going on since the beginning of fiberglass boats. No production boat is made of 100% fiberglass. Fiberglass is very strong but not very rigid, and is extremely heavy. Fiberglass sandwiched with a lightweight (relatively), dimensionally rigid materials like plywood, balsa, or the new foam coring makes an almost perfect hull structure as long as it remains unbreached. When building a hull that will be cored below the water line, areas where the hull will be pierced are usually built up with solid areas of waterproof composite to hold the components that pass through the hull. Where problems usually arise is when modifications are made later by folks that don't know what they are doing such as adding a through hull transducer or an additional through hull for an air conditioning system etc. Any good surveyor would have looked at these areas and tested your hull for water incursion and should have been aware of the materials used in your boat and called them out in the survey (you did have it surveyed,right?). First order of business is to figure how the water got in. Once you know that, as long as the existing fiberglass has not delaminated, the rotten balsa can usually dug out and the void refilled with something more water resistant and you are back in business.

[Ron222]

Thanks for the replies to my question. You probably sensed my frustration with this new problem. As I learned today from the boatyard many boats have balsa cored hulls below the water line. But as DougSea points out all thru hulls must be fiberglassed around the hole to (1) keep the water from reaching the balsa and (2) prevent compression when the bolts or screws are tightened down. This looks like a very sloppy design or construction job by the marina architect or, more likely, Albin's boat builders. The rudder will now be removed (the boat has to be lifted, the struts removed and the core dug out to the extent possible. Then the holes will be filled with crushed glass/ fiberglass, redrilled and, hopefully, the boat will last another 25 years. Although, since I'm 63 maybe all I need is 20 years. The hull was checked with a moisture meter and the problem does center around the struct and rudder. I will update as soon as I have more information. Thanks
Ron
A34 Paumanok
Westbrook, CT

[jleonard]

Reapeat after me...
Boating is fun, boating is fun.
At least it's not mid season.

[DougSea]

Ron,

Check the Jamestown Distributors site for a good write up on fixing core problems. I can't recall the exact product name but it's from Smith.

[Ron222]

Had an interesting conversation with the mechanic working on my rear main oil seal about moisture in boat hulls today. He had a $500 moisture meter and told me how it is very questionable what to do with the information you get from the meter. We went from the boat keel to the boat hull, stern, a composite golf cart, a nearby fiberglass boat hull, to the side of the wood shed housing the boat to our "dry" hands. In most cases the moisture meter says there is moisture (like 14%). It was unusual to get a low moisture reading. We got one on the sunny side of the all fiberglass boat. My rudder area shows 30%. However, the golf cart inside the shed and my hand was at 20%. Most interesting was how the meter reads higher when you slide it down the hull to the painted boot stripe and bottom paint. Just at that paint line the meter jumps higher. Weird. It must be that chemicals in the paint increase the electrical conductance to indicate moisture. Last, when putting the meter on the same spot outside a thru hull fitting and then on the inside at the same point the readings are different. Go figure. I think the bottom line is moisture meters are qualitative only. I was told some surveyors use them to scare the pants off the boatowner. In reality the meter readings can't be fully trusted. In my case there is definitely a moisture problem in the rudder area but using the meter to figure the extent of the moisture problem is not knowable. Maybe taping with a plastic hammer is really the best way to find out.

[jleonard]

I own a moisture meter and agree that it is not the gospel. One must have a good deal of experience to understand what it is telling you.
Did you mechanic have a calibration plate? I have one and it helps get better readings.
What I like to do if possible is calibrate the meter to a known good dry sample of material similar to what you're checking.

[dsax100]

I read a couple of articles on the accuracy and use of moisture meters as marine survey tools. The concensus I got was that they are more accurate when used from inside the hull. They are generally used to confirm results from hull sounding and visual inspection. They're best used to get average readings from structually sound hull sections around the suspect area and then they can be used to help identify the boundry of the water intrusion. One author conducted informal tests on hulls just landed and hulls that had been on the hard for more than a week. He writes about sigificant differences on the same hull in the shade and in the sun as well as between painted and unpainted sections. All of the tests were on the outside of the hulls. Seems like interpreting the meter readings would be pretty subjective and require significant experience.

[RobS]

The meter should be nearly pegged wet when put on your hand. Some meters read % of wood moisture, others just use a relative scale.

[DougSea]

The meter should be pegged wet when put on your hand

Unless you're a mummy Rob. Then moisture is bad.

[RicM]

Let's think about this for a minute...what kind of magic ray could penetrate the moisture proof gelcoat-fiberglass barrier and tell us the actual moisture content of the core material sandwiched within? X-rays? Infra Red? Sonar? The answer is of course, none of the above. Sonar (sound waves) can tell us the difference in density between 2 samples. If we know that a certain area of the hull is sound, and an area of suspicion returns a sonar signature of much greater density, we can assume that the denser area is wet, and by careful calibration come up with a reasonable estimate of how wet, right? So this is not really a "Moisture Meter" but a glorified stud finder correct?

[jleonard]

So this is not really a "Moisture Meter" but a glorified stud finder correct

I believe so.

From a website that discribes how a studfinder works:
When the plate inside the stud finder is over wall board, it will sense one dielectric constant (sort of like an insulating value); but when it is over a stud, the dielectric constant is different. It works on a capacitance differential generated by density difference.

I got pretty decent with mine but did get faked out once and drilled some "core samples" and found dry plywood.

[joe.baar]

Just FYI, last October we had the old transducer removed. The exposed material in the battery compartment - roughly amidships and about 12" to starboard of the centerline - consisted of (inside to outside) about 1/8" fiberglass matt, about 5/8" very hard tropical hardwood plywood in 5 layers, and about 3/8" fiberglass matt. Photo attached, sorry I forgot the ruler. The original xducer hole was cut vertically anyway so the exposed material appears deeper than it really is. Again, this is a 1995 28TE.

IMG_2120a.JPG