Lone Star Medallion II 1966, Oh Scrap!

[GA_Boater]

I sure hope she's a survivor, 64. I went back and looked at her in the water during the weigh-in and she has really great lines.

 

[64osby]

I sure hope she's a survivor, 64. I went back and looked at her in the water during the weigh-in and she has really great lines.

It's interesting, dug a hole in the ply at centerline about 4' away from the transom tonight. Floor was shot but the foam was dry down at the keel. :suspicious::noidea:

 

[64osby]

Thinking way ahead on this project.

The goal is to build an affordable fish & ski. Considered a bowectomy, but I like the lines, the bow access is a great feature and there is a lot of structure provided by the bow setup.

Without having the plywood and foam out I am confident stating there is no substructure below the plywood. The structure for the floor is provided by the foam. IMHO not the best design for a riveted boat.

There a five potential options to get this hull sound and back on the water. After the plywood and foam have been removed the seams will get gluvit or coat it.
At that time I need a plan.

I see five possible options to end up with a sound usable hull.

1) Rebuild per the original design. New plywood, pour in foam, fiberglass the plywood to the hull.Not a preferred option but if someone has strong arguments to convince me I'll listen.

2) Install ribs and stringers , sheet foam and sealed plywood. Much like Starcraft.This would be my preferred method as it is proven to provide a sound hull. The issue with this is the bottom of the hull is lapstruck like the sides. The ribs would only contact the high points.

3)Install stringers only, fore to aft, sheet foam and sealed plywood.I can't recall seeing a hull with stringers only. Would this be enough to form a structurally sound hull

4)Install full height ribs, port to starboard that supports the sealed plywood, sheet foam.

Believe this is a Sea Nymph design for structure, it is also the design of the Lone Star Medallion. The issue would be designing / fabricating the ribs to be in full contact with the flat portions of the lapstruck bottom.

5)Scrap the hull and find a new project that doesn't depend on poured foam as a structural component.

Any input is appreciated. Provide other options. Give reasons why one or more of the options above are a workable plan.

It may turn out the hull has massive corrosion under the foam, but until that is determined the plan is to make this hull seaworthy again.

 

[jbcurt00]

Using flanging pliers, you could bend tabs on the bottom of a full height port to starboard aluminum 'rib' so that the rib is in full contact w/ the hull, stepping up or down w/ the lapstrakes.

Take a LOT of patience and a good deal of masonite to make templates of each rib.... But could be done. Not sure how well ribs riding the 'high' spots of the lapstrake would carry the load of the stringers and the deck very well. And where do you put the rivets if the rib doesn't follow the contour of thee lapstrakes:

 

[GA_Boater]

My couple of pennies. She's 48 years old and still floats - That's a plus. I would clean out the foam and fix any leaks, corrosion if found and reconstruct as originally built. Trying to retrofit ribs and stringers will be hard and the possibility exists for introducing structural weakness by concentrating forces the hull isn't designed to handle. I'm sure there is a resin product that will adhere to AL for the tabbing. And I would do a good paint job inside the hull to hold off corrosion caused by foam to AL contact.

So I don't think any form of ribs/stringers is a good idea and and it's way too early to entertain the final option, scrapping the hull.

Oh, a question - Is this a riveted or welded hull?

 

[64osby]

The Armor-Hull literature item #2 states smooth welded seams, but the only welding noticed so far is in the splash well.

 

[64osby]

Boatnut74 has / had a Medallion that he worked on in 2012.





The ribs are not notched to fit the lapstuck hull. There are 4 strakes (?) on the hull.

 

[jbcurt00]

Hmmm, steps between lapstrakes are smaller then I had envisioned........

Odd that there is more rivets then welded seams. Wonder if it's a mid-year change over hull?

 

[64osby]

Hmmm, steps between lapstrakes are smaller then I had envisioned........

Odd that there is more rivets then welded seams. Wonder if it's a mid-year change over hull?

This is the first year of production for this model. This has the 66 logo. In 67 they changed the name to Chrysler boats.

 

[classiccat]

boy, it's too bad that you don't have drew's medallion design (latidinal rib design with a V5 strake pattern). I see nothing on the exterior that suggests you even have ribs...unless they're welded to the hull skin? :noidea:

a few random thoughts:

• lateral stringers might be a better option for connecting to the hull if you're worried about interaction the faux-lapstrake. Add cross braces (latitudinal) to distribute the load to the neighboring stringers.
• Supporting the deck at the outer-chine will take some thought...try to integrate the sides, bottom & deck using some form of brace...and locking the sides to the bottom hull skin; i'm envisioning some angled brackets similar to what I'm doing on my SS.
• Keep the deck somewhat removeable in the event that you have to modify the supports down the road.

 

[64osby]

jbc - it is interesting that they just spanned the laps on the hull on the Medallions when installing the ribs. I have to believe the strakes provided substantial support to keep the hull from flexing fore to aft.

cc - Not an engineer, nor did I sleep at a Holiday Inn Express last night, but the boat as is with no strakes would seem to benefit more structurally by having stringers running full length.

GA - At this point putting it back together the way it was built is being considered. The structural foam did work for a long time.

I found a blurb on line that stated the foam used was "seven times stronger then standard foam". So that begs the questions. What is the standard foam? What is 7 times stronger, tensile, compression, flex.... ?

A concern for putting foam back in is what density should be used? 2lb, 4lb Do they make a 7lb?

If foam is going back in I might look at attaching the floor in a different method. Part adhesion part mechanical.

There are a few items that bother me about a sealed floor.

It is impossible to visually determine if the boat is leaking.

There is no bilge. There is just a plug at floor level. Do they make a self draining plug? How would you deal with getting water out of the boat?

***This is NOT my boat *** But is what I will find.

 

[GA_Boater]

So it appears that an Amour-Hull II Lonestar is a glasser in tinny clothing. Other than a tin skin, it's constructed like a glasser. In the Fiberglassics brochure drawing of the hull, it looks like a stringer down the center. Any evidence of that in your LS, 64? Also in the pic of "not my boat", it looks like the sole is dished to direct water to the drain plug. With no bilge and the sole at the same level as the drain, this might be a drain method.

Part of this kit- http://www.customrubbercorp.com/plug.htm

The knock against the "duckbill drain" is any debris getting into the flappers holds them open. The linked one is a little different in that it has a plug for the inside of the thru-hull.

I found 2, 4, 8 and 16# pour-in foam at US Composites. A blurb there says (http://www.*****************/foam.html )

• The lightweight foam is commonly used for filling voids, filling under decks and practically any other flotation or insulation application. Higher densities are used for architectural castings, support applications and has virtually an unlimited number of potential uses.

This one presents some interesting challenges.

BTW - the links are to products that are not available in the iboats catalog, especially the higher density pour in foam.

 

[Watermann]

Wow this LS M just keeps getting more and more foreign in the way they built her. Soft of amazing in an odd way.

Hey I like how even the mods get their links censored... sorry GAB. :lol:

 

[GA_Boater]

I try my best to send peeps to the iboats store, but some things aren't on the shelves. The duckbill and 4, 8 and 16# foam for example. I get caught if I try to use one of the seven dirty words, too. LOL

 

[64osby]

GA - I'll check to see if the sole is tapered toward the drain hole. In the pic it does look like it, but on this one it didn't visually look like it.

I did look at US Composite before. I would guess the key property would be parallel compressive strength, 40, 60, 90 250 or 580psi options.

I know the small pieces of foam that have been pulled out are very hard. Can't compress it with my fingers. Green sheet foam is listed as 25psi and that can be squished.

There is no structure in the center. I dug a hole right over the keel and found nothing.

The inside the hull drain might be the correct option. The big issue would be if I use the 20 gallon tank that came with it, if fits great under the splash well but would make access to the plug difficult. Maybe I could foam the tank in below the sole?

 

[64osby]

Wow this LS M just keeps getting more and more foreign in the way they built her. Soft of amazing in an odd way.

Hey I like how even the mods get their links censored... sorry GAB. :lol:

H2O - The old saying "a wolf in sheep's clothing" comes to mind. It's going to bite me.

Glad to see the mods aren't above the law.

 

[64osby]

Moved the boat from the front forty to the side yard. One step closer to getting to it's hopefully winter storage / work place inside the pole barn. Whole lotta cleaning required for that.:facepalm:

GA the sole looks level to me.



Actually did a little tear down.

The Boat came with side panels, set of 3 for each side. Also two trim attachment aluminum angles. But they weren't attached.





But what was attached was an aluminum panel. Don't think this was original. No holes for mounting the panels are in them.





The panels are about 3/16" painted aluminum on both sides and a black plastic material in the middle.

Behind the panels is some wonderful plastic coated styrofoam.



Next up the floor or at least part of it.

 

[classiccat]

the more that I think about this, the more uncomfortable I'd feel about putting any holes (for rivets) in that bottom hull skin; you're asking for stress-related cracks due to flexing since you won't have extruded strakes/ribs there for support.

if you don't go the foam route, some kind of internal skeleton will need to be fabricated. quite a challenge!

The foam route would require maniacal attention to keeping water from getting below deck...which appears to be their strategy. All water flows above deck out a scupper? Completely foreign to us tinheads!

 

[64osby]

cc - I was hoping that sheet foam would have enough strength to work with a stringer or rib set up. I don't think the 3/4" sheet foam rated at 25 psi is enough to support the hull / sole properly without as you say an internal skeleton.

I do have some 20' aluminum C channel that has potential for structure but your point about stress fractures is valid.

 

[GA_Boater]

No bilge and the drain located so high explains the sole being tabbed to the hull. Trying to keep water above the foam. I wonder if you could build a raised triangular portion of the sole against the transom to direct water toward the drain. The only way to dish it is with thin ply and with no stringers there is nothing to hold the center down.

You will need high compressive foam or it will crush over time. And I'm with CC about putting rivets through the hull for two reasons. Potential leaks and stress points.