TOPIC: New Tech Idea for Rotted Boat Floors

Hi I am in process of trying to track down the basic plans for a 1981/82 Shell Lake Inc/ Lund 'Mirado' 16 Fulldeck.

However, I work in aerospace/ prtotyping, etc and it dawned on me that this rotten floor issue is really the one thing that plagues all glassics prior to restoration.

So my idea is pretty simple - why put back all that wood stringer rubbish and cover with floor.

With a 3D scan of the cleaned-out boat bottom - minus the stringers and foam, etc. It might be possible to use a decent machinable flotation foam, break the scanned shape into blocks for ease of handling and machine it.

The next thing is to 3D machine it - simple rough cut is all that is required and epoxy the blocks back into place. The foam should provide all the strength minu stringers.

Next the top of the shape will be watercut into a modern laminate floor and bonded to the foam. I will leave an access panel for the fuel tank or a floor area that just lifts.

For the rotted transom I know of an amazing composite panel used on aircraft floors - I am trying to see what this costs. This will need to be drawn in CAD and similarly machine cut.

I'd probably bond the transom in before the floor blocks so it is bonded with the whole system.

The main idea is that once the crud is removed, there is a process driven way to get a kit of well-fitting parts that custom fits a boat and is super light and super strong - with nowhere for water to be absorbed....

I don't mind others taking this idea - or maybe wishing to collaborate to save MONTHS of time and improve the fundamental design performance.

Sure sounds like you have the know-how and maybe the resources to go for it. I predict you'll turn out one heckuva nice fiberglassic!

pickinboy,

WELCOME ABOARD.

NEAT idea, imVho.

yours, satx

pickinboy et. al.,

I've toyed with the idea of replacing the stringers & everything else with irrigation pipe filled with foam OR simply capped, with the sole laid directly on the pipes.
(IF I can figure out how to reliably fill the holes.)

yours, satx

www.preforms.com/

What are the costs of something like this?

Welcome aboard. I like the way you think. If only we all had those kind of resources I bet you would see it. Sounds like fun. My under seat flotation consists of 3 inch pool noodles with 3/4 inch PVC pipe inside capped at both ends and mounted where the sun don't shine.

Post pictures when you get going. The only problems with your idea I think is cost, and the dizzying array of boats out there. There are a few classics in decent numbers, but a lot of unique boats as well.
Anyway it sounds like fun. I hope at least it is feasible for you so we can see what is involved.
My restoration I discovered had no flotation originally so for my boat your method would have been an upgrade for sure.

Will epoxy or poly stick to these materials you are thinking of using?

There are companies here doing 3-D scans for re-fitting yacht interiors. I priced scanning a smaller FG boat...it is very pricy. Due to slight interior variations boat to boat pieces made for one would not fit another. If you Google "3d scan boat interior" you'll find lots of info like this one www.qualitydigest.com/inside/metrology-article/3-d-laser-scanning-boat-building-marine-applications.html

It would work for new builds where the foam piece could be pressed into the wet resin on the interior of the hull.

I would like to start by saying it sounds like a great idea however, Being in the aerospace/ prototyping I would hope you have an engineering background and part of the studies would have been structural loading which would cover both a chemical compound load abilities as well as materials load ability.
Chemically a epoxy resin, especially an aerospace quality epoxy is a great choice how ever foam is not. When you break down foam what is it? 95% air and 5% resin. If you can acquire foam made of the exact resin you will use for bonding agent then you are some what in a good direction but you still have a problem "breakdown" your resin is going to break down over time.
In a load fixture what is the strongest design? A I beam because the lower flange takes a load and distributes it over the length of the web until it reaches the top flange which in turn goes under tension. There is no structure stronger.
That being said a foam is not able to transfer a load instead it goes into a state of shear where it will basically tear itself apart under sustained or repeated loads.
Almost every single foam on the market "affordable to the general public as well as boat manufacturer is a styrene base monomer and out of all of these there may be 6 that are suitable for direct bonding with epoxy but even these will have a chemical reaction. During a chemical bonding process whether it is a wet layup vacuum or infusion your chemical react with each other. This reaction over time can be catastrophic if you do not use the correct chemicals.
I inspected a airplane cross cut section of a wing yesterday. This wing was manufactured to EXACT standards of the FAA and was a vacuum layup epoxy and foam core. The inspection showed the inner laminates had began to release (inner skin released from the foam) due to chemical cross link bonding that had in effect killed itself during a 10yr shelf life. Shelf life is right the product was never installed and sat on a shelf for 10yrs. A Brand new wing is trash because of difference in chemical properties that attacked each other over time and resulted in a break down...
Now take a piece of foam and place it to a piece of wood and load the two and see who gives first.
Wood can not be beat in the test unless you use Penske board or Cossa board. But I don't know too many people who can afford a 4'x8'x3/4" sheet for $500 a pop.
Like I said you have a great idea but please research every aspect of the design before you do it. A resin is only as strong as the glass being reinforced and vise versa same goes for your stiffeners

all very good points.

I may rethink the the idea a little - especially in regards to the adhesives.

As you say - if the load can be transferred into the skin (ie. the floor) it will be very strong. Also what kind of shearing loads will the bottom of boat/ floor see?

I can imagine the ability to withstand flex being the greatest challenge.

The scanning will be via a borrowed or rented scanner.

You can build a glass stringer system to bond to the floor but I would inject the foam and shave it before you bond it. The exotherm of the foam will distort your hull if injected after bonding the stringer system. As for the scanner. Love the idea. it will give minimal prototyping time because it will be a direct fit from the get go. Also make sure you hull and stringer system if used are of the same material and it would be best to make up your own bonding putty with the same resin used for layup so you do not incur two different exotherms and cause hull distortion. Good luck and keep us posted on the progress

Are you suggesting a boat bottom and boat floor without structural beams between them? Foam blocks fitted next to each other would not keep the boat from flexing itself into destruction on the water. I pulled out the inner stringers/stiffeners from a classic fiberglass boat way back. It lasted three weeks.

I'm afraid that once you do the math, you'll find that cost wise, it doesn't pencil out. That model / year boat in excellent shape is worth perhaps $2,500. The materials you propose to use are exceedingly costly, and the process very labor intensive. Of course - it's your boat & your choice. If you use the correct type of wood, and if it is correctly sealed and installed, the boat will give decades of rot-free service.

The times they are a-changing'. Great concept guys and I'm sure tech up to date. Some of us older guys still like the thrill of the chase though. Rebuilding something that was broken. There are those who rebuild a boat which would encompass your ideas and there are those who "restore" a boat to factory specs. If price dictates whether you rebuild or restore the hi tech scanning etc. is probably out of reach for a lot of us.
Good ideas and keep up that way of thinking, it's the future that has become the present.
Cal

The floor on my 17ft Skagit has fiberglass stingers covered with honeycomb aluminum. The previous owner did it and bought the aluminum through Boeing surplus. Solid floor that won't rot. Clint

Strobee,

Tell us more about that aluminum floor.
How is it attached to the stringers and the hull. Pics if possible.
Thanks

Maybe I'm too old to change but it all sounds like a great deal of time, money and effort to re-do that which has already lasted about 50 years...which makes the wooden stringer/marine plywood approach proven "technology." When you throw in foam floatation, CPES, 3M 5200 and fiberglass resin, I really don't see the need for further improvement.

Once the fiberglass stringers are dry, why do yo want anything inside them. Fiberglass stringers, by definition, are stiff by them selves, if a bit heavy. Addinf weight inside them, adds weight with more strength, but one does not need that weight and strength. Too much weight makes for a slow and poor performing boat.

I have started realising just how little investment was put in some of these boats However, there are a few cheaper scanning systems - one that is coming out soon from Kickstarter and some exsit already for the XBox Kinect scanner ...... what I am doing is trying to get my idea down to the costs I now know people are looking for - 50 bucks here, 100 buscks there, etc....

www.kickstarter.com/projects/occipital/structure-sensor-capture-the-world-in-3d?ref=home_popular .

Have the motor off and on a stand and starting to split the top off the hull. I need to send some pics from projects soon. Thanks for all the advice and help so far.

there is more than one type of composite panel - great idea though - exactly where my mind is at.

pickinboy,

WELCOME ABOARD.

yours, satx