Fer-A-Lite

Exactly....

 

Build it from wood, and glass it inside/out and give it final 2-3 layers of epoxy. Far cheaper, less work and better.


We don't build houses from stone anymore, concrete is faster, cheaper, better. Same with other materials over concrete or fer-lite, whatever.

 

But a house is ostensibly a square box, not a 3D shape with complex curves. Nor must it be subjected to a very harsh and corrosive environment coupled with extreme structural loads.

So, that is a tea-ny wea-ny bit different in my book!

 

Is this the boat you are talking about

Pdw,

St Cloud Florida, and Shaffer rang a bell, so I went through all the old pictures that I got from Platt.

This is the only one I could find this morning, but I think there may be a couple more.

I was unable to find any information about the boat a couple of years ago when I was researching, but it may be worth my taking another crack at it.

 

This is the Brewer Gitana, I agree I think the photo is of the Colvin design, so I will contact sailgitana and see if they can trace lineage back to Shaffer in St Cloud.

 

I made a calculation of $15,000 for a 3,500Lbs boat hull weight in ferolite only. (without the steel)
Could confirm or infirm with real numbers we can verifies?
I took the figures on your website, and perhaps I am wrong, but it seams way too expensive.

 

Daniel,

We have always been very clear that FAL is more expensive than FC, but for that difference in price you get a superior and longer lasting hull.

You need to go back and check your numbers

6 Units of Fer-A-Lite would work out to 3600 lbs in Fer-A-Lite/Resin mix.

6 units at full tilt price (which I have yet to sell at ) is $2850.00 plus 6 barrels of resin. Unless of course you are paying in the neigborhood of $2K per drum, in which case I need to introduce you to a buddy of mine who needs to make some cash.

That is also more than enough material to build a 50' hull in most cases.

Here is the other thing to keep in mind. Since as the manufacturer we do not know what % of steel content the end user will put into the matrix, we calculate the amount of Fer-A-Lite for a given hull without any displacement of material with steel.

So, it you are building a 1 inch thick shell w/ 50% of the volume consumed by steel, you would only need enough Fer-A-Lite for 50% of the total volume of the hull matrix.

But in reality, most properly built hulls are in excess of 50% steel content. So one should not just focus on the cost of the Fer-A-Lite.

And of course keeping in mind that the hull is such a small percentage of the total cost of the boat.

 

Read through the entire build process.

You do not have to skin it with glass, most boats were skinned with either brown craft paper or such, some were skinned with glass during construction.

The material is placed on the plastered FAL while it is still uncured. You can then take a towel (not a trowel, but a towel) and smooth over the covering material while it is in contact with the uncured FAL, basically allowing you to fair the material pretty close, you then go back and add catalyzed resin to the material to fully saturate it, before the material finishes curing.

This outer skin becomes an integral part of the hull.

Most folks reported, from what I read from the letters from owners/builders that I received from Platt when I bought the company, that the hulls actually needed a minimum of fairing at the finished stage.

Those that used Wireplank needing the least amount of fairing.

Naturally, the better job you do fairing the armature, the easier it will be to fair the hull.

Regardless of the skinning material, we still recommend a good epoxy barrier coat on the finished hull. That is not something that Platt recommended, but we as the current manufacturer strongly recommend.

As I have stated before, I am aware of the limitations of Polyester resin, I am also aware of the vast number of boats that have been built professionally and as one offs out of the material.

It is just prudent to seal the hull, regardless of the fact that we state, and have tested to proof, that FAL does not absorb moisture, and it is impossible for moisture to wick its way through the material like FRP.

 

Perhaps this thread needs a remedial reading class, as most incorrect comments popping up are clearly due to the fact that folks are conveniently leaving out, or ignoring the information.

But then I cannot fault anyone, due to the vast amount of inaccurate assumptions, unsupported wild claims and outright twisting of the data being made by supposed professionals.

Do you folks keep E&O and liability insurance in place?

Because after all, as I was advised, its all on the record here.

 

PDW--from my understanding--its the shell that is the strength of a hull..otherwise would't you use large heavy frames and then a light shell for steel?..even colvin suggests that a boat can be built using frameless designs.
provided the material is thick and strong enough...????
of course there WOULD have to be some longitudinal stiffening...but it would probably need to be minimal... i think its the other way around- the wire plank holds the goo which is the strength of the hull...

 

Technically no.

The “strength” of…well anything, is owing to the material properties. How ‘strong’ something is, is related to its strength, which is directly related to the material properties. This is measured in terms of “stress”, which is defined by force/area.

So for any unit applied force, over a known area, the stress can be calculated.

For example, if the unit force is say 1kN and the cross sectional area is say 10mm^2, then the stress is 1000/10 = 100MPa or 100Nmm^2.

So if the material is say aluminium and if normal 5000 series plate, this ‘yields’ at 120~125MPa.

Thus the 1kN load on the cross-sectional area of material, if aluminium, is close to failure. There is a factor of safety of 125/100 = 1.25

If the material is now grade A steel, the yield stress is 235MPa, thus a FoS = 235/100 = 2.35. Therefore we can say that the steel has nearly twice the amount of ‘strength’ as the steel.

If the material is FC, this ‘yields’ around 50MPa, therefore with this 1kN applied load the member has failed.

So, how do we over come this, how can you make the less-strong or material with less strength not fail? You make it “stiffer”.
Stiffness is a product of EI, the Young’s Modulus (E) and the second moment of Inertia (I)of the member.

Or put more simply, if there is more “area”.

So at 10mm cross sectional area, the FC would fail. If the area is increased from 10mm^2 to say 100mm^2, a ten fold increase, the stress = 1kN/100 = 10MPa.

The material no longer fails.

So the “strength” of any hull is related to the mechancial properties of the material and the amount of material that there is (area), to resist the loads being applied to it.

 

Odd,

Everything I have read from the likes of Brookes, Bingham, Colvin, Samson etc...

The armature (shell) is where the finished hull gains most of its strength.

I do not think you are looking at this as a composite. You fail to recognize the added stiffness and strength gained by a combination of material.

The formulas that you are using are I believe a single material construction.

And since his question was about the strength of the armature and not the plastering material what exact relevance does it have.

 

Just to make sure we are all on the same sheet of music

Regardless of whether you use portland or FAL, the primary strength of the hull comes from the armature.

The plastering material is there to primarily keep the water out.

The difference in using Portland or FAL is quite simply:

superior toughness, ability to withstand repeated impacts
seals the armature more effectively to prevent moisture getting to the armature
vastly improves the survivability of hull re: armature health, impact resistance, etc..
the ability to plaster in convenient increments

It is a stronger material in the finished composite than what it is being given credit for.

Yes, it is much more expensive than Portland. But it is also a far superior product to use in this type of construction so that you do not have all the issues associated with FC, and those associated costs. You will end up with a boat that will have a far more favorable resale value than FC.

And here is the kicker folks, from what I have gathered in following up on FAL and the FC boats that I have run across. Resale value was not at the head of list of why they chose the method they chose. So using that argument does not really hold alot of water so to speak.

Most builders of these boats were either home builders or someone who had a yard build it for them.

Of most of the FAL boats I am tracking, the original owners owned them on average for over 25 years.

You don't build a FAL boat to flip and make money on, you build it as an investment in your way of life, more labor intensive/costlier to build, but far less maintenance and anxiety over the lifespan of your ownership. When you consider the differences in cost over a 25 year ownership period between building and maintenance as compared to frp, steel, aluminum, wood etc... it becomes a no brainer.

 

From your website
Fer-A-Lite Unit
1unit=55 bag= 115lbs
$478.25

So what it means in reality?
I divided 3500Lbs by 115lbs and multiply by $478.00 and find: $14,547.82
I don't find $2,500.00 like you find.
But as I said perhaps I am mistaken.

 

Hi Daniel,

Keep in mind that each unit of FAL contains 55 bags of dry mix. You mix each bag with 1 gal of boat resin which weighs on average 9 lbs.

So 9 lbs of resin , plus 2lbs of drymix = 11 lbs times 55 = 605 lbs per unit mixed.

So you would need 5.78 units to reach your 3500 lb target

6 units @ $478.25 =2869.50

6 55 gal drums of resin @ 1000.00 = $6000.00

So 8869.50 less steel.

But how much does the entire target hull weigh, what percentage of that weight is steel and how much FAL?

More importantly how many square feet of hull, how thick of a hull does the design call for and how much of that volume (thickness of hull * sq.ft of hull area) is going to be steel armature.