1964 Lone Star Medallion

[DAHoyle]

Nothing actually new to report, but I do have some observations, material selections, and maybe a few questions.

I am putting a materials list together, and have some observations to share. The first thing I want to cover is the flotation foam, and the design I have envisioned for installing the absolute maximum possible. Unfortunately, I am working in Houston for the foreseeable future and don't have access to dimensions, so some of this is going to be nothing more than educated guesses.

The material I am going to use for flotation is a product by Dow. I have had extensive exposure to this product for a very long time and have seen it used in many applications that are far removed from it's intended purpose. I have dug it out of saturated ground after decades of exposure to moisture, and have never any saturation at all, so I am confident of it's long term effectiveness. I will do some flammability testing, and also dump some gasoline on it, to see how it reacts, but am pretty confident it is safer than the original formulation that was installed in the boat.



Not 100% sure of the density right now, but it is pretty light. Wouldn't surprise me to learn that it is a bit higher than 2 lbs tho, because it has a tiny cell structure. one of the properties I like about it is that it is extremely tough. Anything less sharp than a brand new razor knife tends to tear it. On the other hand, once one side is scoured, it breaks very cleanly.

 

[DAHoyle]

Knowing the size of the floor board gives me a rough estimate of the amount of foam I can get beneath it. given a width of 5'and a length of 10, and an estimated average depth of approx. 8", that gives just over 20 cubic feet of flotation under my feet. I could put it all in a CAD drawing, but not going to bother for now, and it isn't really relevant at this stage, because I am guessing at some of the dimensions. We'll just call that the best case, and allow for a 10% reduction so we'll knock it down to 18 cubic feet. Since I am feeling generous, I'll call the foam a 4 lb density, but I know it is less than that. Either way, I am already over 1000 lbs of buoyancy just under my feet. That doesn't count what will be hidden behind the side cladding. Best guess there will be approx. 5 CF on either side, which gets me up to 28 total, or over 1600 lbs of floaty stuff. Each piece will be cut to fit to form a uniform fill with no voids. Once a section is fitted, the pieces will be removed, and epoxied together, to create blocks which will be approx. 3-5 CF. Channels will then be routed on the side facing the skin to allow a free flow of water to the keel and then the bilge.

I am somewhat surprised that the volume is as great as it is, especially given what I removed from the boat. I am sure that at one point or another, it was not returned to its bay when the floor was replaced. I don't think I removed a quarter of that volume.

If there is any reaction to gasoline when I test it, then I will encapsulate each block in some sort of impervious barrier, most likely epoxy.

 

[DAHoyle]

Now, here is where the requests for information come in. I fully intend to put more than the rated power on the stern of this thing. I am leaning towards a pair of 60's. I know, they aren't as efficient as a single 120, but the shape of this hull, and the width of the transom is screaming for two outboards.

Either way, I find it somewhat surprising that there are no stringers in the design to help spread the load. My idea is to build a structure which ties the top of each of the ribs together in a way that prevents any flex, and transmits the force on the transom more directly into the hull, and at the same time adds some additional rigidity, which seems lacking. The majority of the energy seems to be transmitted thru the transom laterally, to the skin of the hull. The only structure which stiffens the sides and keeps them from bowing out, is the gunnel. The gunnel is pretty robust, consisting of a wide extrusion, so it most likely is fine, but as I said, I intend to add a bit more power to the equation.

What I would like to do, is create a corrugated aluminum subfloor, approx. 2" thick, and with spans of 2"-4", riveted to the ribs at each point of contact. Most likely material would be .060" thick, and utilize the shape rather than the bulk for rigidity.With that piece contacting the bottom of the transom, some of the force would be transmitted into it, and subsequently thru the ribs into the hull. My concern is that it may create some microscopic flexing at the point where the ribs are riveted to the skin. Any thoughts on this, It is way out in left field, but the simple fact of the matter is that I have never found an object which I didn't think I could improve, or at least tailor more to my liking.

I'll try to put together a sketch to illustrate what I am thinking.

 

[Willyclay]

Any thoughts on this, It is way out in left field, but the simple fact of the matter is that I have never found an object which I didn't think I could improve, or at least tailor more to my liking. I'll try to put together a sketch to illustrate what I am thinking.

I remembered this old thread by member Tim Frank that impressed me with his fabrication of new transom knees for his tinny.

http://forums.iboats.com/forum/boat...g-and-hull-repair/275209-transom-repair/page2

Check out the pix in Post #16. Not exactly your situation but maybe creates some thoughts to consider. Good luck!

 

[DAHoyle]

I remembered this old thread by member Tim Frank that impressed me with his fabrication of new transom knees for his tinny.

http://forums.iboats.com/forum/boat...g-and-hull-repair/275209-transom-repair/page2

Check out the pix in Post #16. Not exactly your situation but maybe creates some thoughts to consider. Good luck!

Thanks for the link. Even if I don't use it exactly the same way, I love looking at pics of how things are assembled. Very elegant solution to his dilemma. I guess we all have things we would change, or more precisely, wish the manufacturer had changed. I love the Stringers and knees on the old starcrafts (almost bought a 67 Jupiter instead of this boat) but I like the way that Lone Star did the ribs. I went with the Lone Star because it was more generously sized. Maybe 6" deeper hull and 10" more beam. Not saying that there is anything wrong with either, would just prefer the full length stringers and full height ribs. Sadly, they don"t really work together. That is why I am contemplating adding a full width "stringer" approx. 10 feet long tying all the ribs together. The trick is to get someone to make approx. 30 precise breaks in a piece of sheet aluminum. I have found a company which will form channels with flanges, which is very similar to what I envision, so I may contact them for a cost. An added benefit would be that raising the floor 2" would give me room for approx. 8 cubic feet of foam. I really don't see a downside, with the exception of a few extra lbs. I can live with that. Properly executed, there would be at least one stringer directly in line with the thrust of each engine.



For the record, I tested the blue Dow foam with exposure to gasoline today. It does degrade it, but not nearly the same way the old original Styrofoam was melted. There was very little indication that anything had occurred, until I pressed my thumb into the area I saturated. Just a few seconds contact with gasoline, allowed me to press my thumb into the foam approx. 1/4 inch.

 

[Willyclay]

I went with the Lone Star because it was more generously sized. Maybe 6" deeper hull and 10" more beam.

I had a 1966 Lone Star Medallion II for 23 years and loved it for the same reasons you cite as well as the beautiful "clipper bow". A rotten transom, floor and lots of corrosion from the saltwater finally did mine in which is why I joined the iboats.com forum in 2006. Good luck with your mods!

 

[frzncstrd]

Does the medallion have a solid aluminum transom? I am considering an aluminum to swap out with my rotted out glass boat, but the tin i found has a rotten floor.

Any tips on what to look for on aluminum boat?

Thanks

 

[jbcurt00]

Franz, please dont post to inactive topics, after 90days w out a post, let it be for research only.

See my post in your topic