1950's Raven sailboat (Cold molded hull questions)

Discussion in 'Sailboats' started by CloudDune, Jun 29, 2022.

  1. CloudDune
    Joined: Jun 2022
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    Location: Blue hill maine

    CloudDune Junior Member

    Hi all! I purchased a 1950's 25 foot Raven class sailboat last fall. After a winter of interior work I have flipped the boat and moved on to doing repairs to the hull. The hull is 5 ply of mahogany strips cold molded and of course has 70 years of aging repairs and issues to deal with. I have a few questions about working on such a hull.

    1.) I am currently repairing issues by epoxy laminating layers of mahogany, my question, how is this different from using fiberglass? won't the new layers of epoxy soaked mahogany act similar to a fiberglass patch?

    2.) The hull is down to bare wood on the bottom, how should I go about preparing the hull to be painted? it appears to have had multiple layers of ablative bottom paint in the past... should I use something like a two part epoxy paint? or coat the hull in a few layers of epoxy and then bottom paint? (I want to avoid encapsulation but I also want to provide a level of stiffness and a way of strengthening the old wood)

    3.) Some of the bronze fasteners (screws) in the hull have become exposed, these have a patina of corrosion on them.. these fasteners are used to hold the seats, runners, and so fourth to the hull. Should I drill these out and put larger screws in? another thought is to remove the screws, fill with epoxy, and re-insert the screws.

    Any advice would be much appreciated!
     

    Attached Files:

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  2. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    great post!

    I have a cold molded 1960 Carver out back that needs a stem repair and I am anxious to do it soon.

    Lamination repairs must be done very carefully on these. You can't really jist cut put a piece of hull and glue a chunk of mahogany in the hole.

    I am a big fan of Interlux 2000e. I would use it as primer. Then I like Petit Old Salem for boats in freshwater, but for saltwater, use what is locally preferred.

    For fasteners, if it ain't broke, don't fix it. If there is a concern about sealing screws, I use epoxy if you bright finish. I do recommend extra caution on any screws that penetrate the hull where water can stand. Remove them, carefully overbore them 2-3x, fill them with thickened epoxy, rebore and seal screw with 4200 or pref sealant. The easiest way to mess these boats up is a bad seal on a screw hole or water collection at the keelson or transom/hull intersection inside.

    Hope you are wearing a quality respirator removing that bottom paint.
     
  3. wet feet
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    wet feet Senior Member

    Are the mahogany repair sections being inserted into the same spots where the damage was or are they being added to the original material?In either case they should have a similar level of stiffness to the original hull.For primer,why not use a high build 2 part polyurethane?

    For the screws that are coming to the surface,the simplest solution is to do nothing.The next simplest is to remove the screw and increase the depth of countersink a hair,before replacing the screw.
     
  4. CloudDune
    Joined: Jun 2022
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    Location: Blue hill maine

    CloudDune Junior Member

    First off thanks for the great advice. I wear a respirator religiously as I find myself working with a lot of dust/chemicals. Plus it would be a tragedy to develop an allergy to epoxy..

    In terms of the mahogany repairs, my plan is to cut/chisel/route back the layers and lay the new laminations in the direction of the previous wood grain. None of the mahogany repairs go through the hull so that makes it somewhat easier.

    As for the screws, would you say 4200 is better than simply encasing the top of the screw in epoxy? or is the worry it will move around over time and open up?

    And yes, it had some series issues around the transom/rudder through hole which I repaired from the inside.
     
  5. CloudDune
    Joined: Jun 2022
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    Location: Blue hill maine

    CloudDune Junior Member

    The hull repairs are what I would call somewhat small, in this case, I'm not sure I should be worried about stiffness, the new mahogany I'm working with is about all I could get my hands on around here!

    As for the hull paint I like the sound of both the interlux 2000e and a 2 part polyurethane.. my main worry is creating a water tight encasement, I have read mixed things about whether a hull of this nature should be totally sealed off, or left to somewhat breathe..

    I will post some photos of the main areas in need of repair
    Note: The white filler and most everything else are past repairs I have recently uncovered.
     
  6. CloudDune
    Joined: Jun 2022
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    Location: Blue hill maine

    CloudDune Junior Member

    The bow area is obviously in need of a lot of attention..
    The round spot that goes through 4/5 layers was done by the previous owner so I can only assume there was a good amount of rot/dry rot in that spot.
     

    Attached Files:

  7. fallguy
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    fallguy Senior Member

    A cold moulded hull does not follow the same rules as a conventional wood hull. The amount of movement it will see is minimal. Seal it.

    Am a bit confused by the pictures. The hole repair was exceptionally done, but I see an area that looks like it needs epoxy putty work and has cracks. Img 1731 and 1733 look like it needs some more love before paint,,,what am I looking at here? It looks like the bow, but it looks like some fairly open wounds that need filling.

    No rot can remain. That is an imperative. If any exists, it must be cut out. A dremel can assist with small amounts, an oscillating tool for larger amounts.

    This boat would benefit, after finishing the repairs from about 3 neat coats of epoxy after any major fairing. They would be done about 8-12 hours apart. Then sand with 120-180 for the 2000e.

    These boats were made to be fully sealed. Layers of mahogany were laid atop each other and the final glued up item was put in a massive vac bag and the air removed.
     
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  8. CloudDune
    Joined: Jun 2022
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    Location: Blue hill maine

    CloudDune Junior Member

    Yes, IMG_1731,1733 are the bow area still being worked on. In those photos I have just begun to remove rot/dry rot.
    I say dry rot because its not what I usually deal with, rather it seems some of the mahogany in these trouble areas has become brittle and weak. I plan on removing everything I can, before the epoxy coating and 2000e.
     
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  9. fallguy
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    fallguy Senior Member

    The dry mil thickness of epoxy at 2 oz/sqyd is about double most any paint.
     
  10. DCockey
    Joined: Oct 2009
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    Location: Midcoast Maine

    DCockey Senior Member

    The boats described were almost certainly not "cold molded" but "hot molded" using a resorcinol or phenol-urea glue. The surfaces were sealed with paint, varnish or similar. No epoxy was used.

    Standard methods used for repair of cold molded hulls using epoxy are appropriate for hot molded hulls.

    A "patina of corrosion" on the surface of bronze fasteners does not affect the strength of the fasteners. There is no need to protect bronze fasteners from exposure to water. If the fasteners are brass with zinc rather than bronze then de-zincification is a major concern.

    CloudDune's location is given as Blue Hill, Maine. Hamilton Marine in Searsport is 35 minutes from Blue Hill and carries a large selection of bronze fasteners.
     
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  11. fallguy
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    fallguy Senior Member

    Were the Carvers built in the 60s also hot molded?

    I knew the process involved vacuum and oven, but this is the first time anyone has ever called it hot molding. Written word can be toneless. I'm sure you are correct.

    What did the heat do?
     
  12. DCockey
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    DCockey Senior Member

    I used "hot molded" in quotes to differentiate the process from the newer cold molding. I don't know what the process was called in the 1950's. It was essentially creating a large piece of smooth plywood molded in the shape of the hull. The heat was used to set the glue in a much shorter time than would have been required if the glue was left to set at ambient temperatures, which was important for production building.

    Photos of Carver wood boats show lapstrake planking, similar to Lymans and others. Those hulls were built with each plank being an individual piece of wood, sometimes plywood. That is a fundamentally different process than "hot molding" or cold molding.
     
  13. fallguy
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    fallguy Senior Member

    Carver started lapstrakes in 1963. Prior to that the Carvers were laid up with African Mahogany strips over a mould. The bottoms had 10 or 11 layers and the sides had 5. The layers were all laid and the whole boat and mould bagged and evacuated and rolled into an oven (for glue setting as you describe). I have one of them in the back with a broken stem that needs a week or two of repair.

    Here is one of the pre-'63 Carvers.

    Carver https://www.ladyben.com/power-classic-wooden-boat/68140-carver/view-details
     
  14. fallguy
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    fallguy Senior Member

    Here is mine, I am having a time finding the newer pictures.

    The strips were so beautiful, I kept the boat bright, even though the strips are diagonal. This was prior to varnish or between coats.

    Carver in garage https://flic.kr/p/cGnHmd
     

  15. xkdrolt
    Joined: Dec 2022
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    Location: Westford MA

    xkdrolt New Member

    That is a very fast boat for its day. John(ny) McAleer was the designer ca 1949-1950 out of Weymouth-Quincy MA area. One of the earliest owners eventually had FTD against much larger meter and sq meter class yachts when racing in Marblehead. I think there was a demo grudge match held against other similarly sized boats in Long Island Sound and the Raven cleaned up by planing away. Do you know the original sail #?
     
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