Project Star-Lord, Electric Trawler Conversion

Discussion in 'Boat Design' started by jddcircuit, May 30, 2019.

  1. jddcircuit
    Joined: May 2019
    Posts: 4
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    Location: St. Pete, Florida

    jddcircuit New Member

    I recently acquired a 1972 Gulfstar 43' Trawler with the intention of converting to solar hybrid electric.

    My electric drive will consist of two salvaged Toyota Prius electric transmissions, Tesla battery modules, and solar panels. I may keep one of the prius gas engines for use as a generator to charge the batteries.

    I have removed the flybridge to not only clear a fixed bridge in my neighborhood but also to fit my solar array.

    Here is a youtube video of my boat with some commentary on my conversion plans.


    Right now I am fighting with hull blisters and delamination below the water line. I am not sure if this hull is going to be salvageable. I really hope so. I have fallen in love with the boat.
    blister1.jpg blister2.jpg blister3.jpg

    I have experience hacking the Prius motors for some of my electric vehicle projects. I will be doing all my own custom power conversion and battery charging and monitoring electronics and software.

    I do not have much experience with the boat stuff like fiber glass blisters, structural or stability concerns, hull designs, prop selection, etc.

    I picked this hull because of it's sailboat like shape. I assume it will be efficient as a go-slow displacement electric trawler. I welcome all advice and opinions regarding my conversion and expected pitfalls.

    My short term goal is to refinish the bottom, pull both engines, and then float the boat to my dock where I will begin the electric drive install while in the water. If none of this works out I may just end up with a floating guest house and solar array to power my home.

    Thank you
    Jeff
     
  2. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    Looks like a good hull design for conversion, it can carry the weight of all the batteries that will be needed.
    The bottom looks to be in very bad shape, it will require removal right down to solid substrate with the use of a planer specifically designed for that. Then reglassing, barrier coating, and bottom paint.
    Is the whole bottom in the same condition as the sample shown?
    You can do it yourself, but its a brutal job, I’d get some estimates first, especially before spending anything on the solar /gasoline/electric conversion, which sounds like an interesting proposition!
     
  3. jddcircuit
    Joined: May 2019
    Posts: 4
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    Location: St. Pete, Florida

    jddcircuit New Member

    My hope is that the entire hull is not like the photo. So far I have only cut open areas that sound with hammer thud or show bulging. I am batting a 100% so far finding severe delamination. I am scared to test an area that I think has good lamination bonding. If the entire hull is like this I assume it is a lost cause.

    I will continue to expose suspect areas and then evaluate whether to continue. One path may be to epoxy and glass patch the exposed areas, barrier coat, and bottom paint.
    Jeff
     
  4. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    Go ahead and sample some areas that you think are good.
    Also grind down to solid glass an area you’ve exposed, you need to know how deep the damage goes.
    It almost looks like it might have been previously, although poorly repaired, possibly sprayed with chop?
    Research the hull, to try and determine original layup, so you know what you’re working with.
     
  5. jddcircuit
    Joined: May 2019
    Posts: 4
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    Location: St. Pete, Florida

    jddcircuit New Member

    I am continuing my exploratory surgery.
    I can't tell if the mat skin is laid or sprayed or ? I am trying to figure out.
    I do think it is original from the mold with how smooth and shapely it is. The skin is different thicknesses in areas.

    My damage so far seems pretty consistent in depth. The first woven layer and next woven layer peel right apart.
    Probably a manufacturing defect I assume. The mat fiber skin and first woven layer seem to be well attached.

    Hopefully more knowledgeable people in this forum can shed some light. I might not know when to pull the plug.
    Thanks
    Jeff
     
  6. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    The photos seem to indicate that the hull may have been repaired by spray with chop, and the fact that the thickness varies substantiates this. It should have been finished with a woven fiberglass cloth, not chop or matt.
    Unfortunately, this is not a great way to repair a damaged hull, as chopper gun laminates are notoriously inconsistent, and chop strands love to wick up water.
    If you plan on using the boat extensively, it should get a proper/appropriate bottom job, but if it’s just to be a “dock queen” as you hinted earlier, you might get away with less costly treatment.
    I have seen boats that had coal tar epoxy applied over clean sound substrate survive many years tied up to a dock with zero maintenance.
    Having been through a few blister nightmares myself, my personal recommendation would be to look for a vessel with a sound hull and trashed drivetrain, as you’re replacing that part anyway.
     
  7. jddcircuit
    Joined: May 2019
    Posts: 4
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    Location: St. Pete, Florida

    jddcircuit New Member

    I have ground off all the bottom paint.
    My speculation for the history of this hull is that the gel coat was removed in the past probably because of blisters or gel coat failure.
    Some large blister repair is apparent and seems to be holding.
    I am not sure what dry out time they gave or what type of barrier coat they applied.
    Perhaps exposing the fibers with the gel coat removal turned the hull into a sponge and exacerbated the problem.
    Or they sealed in the moisture with the barrier coat or they didn't even use a barrier coat.
    I now have new blisters often next to and connected to the previous repair.
    Perhaps the hull is saturated with moisture and has a compromised layer bonding throughout.

    Aborting will be very painful but continuing may be worse. Not sure yet.
    I have opened up probably 40 dinner plate size blisters with vinegar like syrup pouring out.
    I pressure washed them and ground them with beveled edges back to what appears to be sound lamination.
    It looks like I could repair them but afraid they or others will return in short order.
    This seems like a lot of blisters to me.

    I am very unsure with what decision to make.
    I would like to have a hull that will last for quite some duration.
     
  8. kapnD
    Joined: Jan 2003
    Posts: 507
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    Location: hawaii, usa

    kapnD Senior Member

    The hull can probably be saved, it’s just up to you how much you are willing to put into it to do so.
    To be done properly, the entire hull from the waterline down must be peeled to identify the problem areas, which could be the whole hull, or just parts of it, you won’t know which until the whole thing is exposed.
    Many blister repairs are done piecemeal, or incorrectly, or on a restrictive budget, which is only a temporary solution.
    It looks to me like this was the case with the vessel you have acquired.
     

  9. JSL
    Joined: Nov 2012
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    Location: Delta BC

    JSL Senior Member

    built in 1972.......hmmmm- warning bells
    This was just before the Arab oil embargo (1973) where MANY boats had fiberglass issues.Some builders had to deal with 'watered down' (with styrene) polyester resin. If this is an early victim it could be very prone to moisture absorption. Good idea to thoroughly check the laminate.
    A shop I worked at used to test each resin batch sample and we eventually found a good supplier. More expensive, but less of a worry.
     
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