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Rust holes under fuel tanks - common on the Offshore??

Discussion in 'Chris Craft Roamer Yacht' started by bearhair, Sep 8, 2009.

  1. bearhair, Sep 8, 2009
    #1
    bearhair

    bearhair New Member

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    Location:
    kingston, ontario
    Looked at an Offshore on the weekend and thinking about purchasing as a project boat. It had the name "Wet Dreams" painted on it. Could not find a hull number. Owner said he bought from a friend who brought it up from New York state several years ago. Everything wood is a rebuild except the v-berth. Visual inspection of the hull showed 2 holes - one on either side under the fuel tanks. Just wondering if it is a coincidence that both sides have rust holes or if there is something else going on.

    Also, is it safe to assume that since previous owners let the hull deteriorate to the point that rust holes developed that there are probably a few more that I just couldn't see. Or is sandblasting a hull like opening a Christmas present from the in-laws, you just never know what to expect - could be good, could be ugly?

    Thanks
  2. Laurence, Sep 8, 2009
    #2
    Laurence

    Laurence Senior Member

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    Unusual for Offshore

    Having rust spots under the fuel tanks seems odd as the Roamer Offshore has the fuel tanks under the pilothouse in the forward third of the hull. Also the fuel tanks are elevated and not in contact with the internal hull plating so I do not see the connection with rust.
  3. K1W1, Sep 8, 2009
    #3
    K1W1

    K1W1 Senior Member

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    Hi,

    Is i possible that there are stringers in the same location or close to it as where the rust is that have no drains or limber holes in them.

    Water from leaks into the bilge or behind linings where it remains unseen for yonks or condensation that can't dryout or drain away can often be the root cause of shell plating thinning.
  4. bearhair, Sep 8, 2009
    #4
    bearhair

    bearhair New Member

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    Location:
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    I checked the areas for rust where you would think water would puddle (bilge area, midline) and found no flaking rust or such. Definately surface rust but nothing that appeared that deep.
    These rust holes under the fuel tanks are well away from the keel toward the outer edge of the bottom where one would assume water inside the hull would run down towards the keel and not puddle causing a rust hole.

    I guess if it is not fuel tank related and just a coincidence then there is no problem to fix other than the re-plating the sections.
  5. Oneiros, Sep 8, 2009
    #5
    Oneiros

    Oneiros Member

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    lulea Sweden the land of the midnightsun
    hi the best way is to sandblast the hole bottom.My rivera37ft was in verry bad conditions have replating 20m2 of the bottom
  6. K1W1, Sep 8, 2009
    #6
    K1W1

    K1W1 Senior Member

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    Hi,

    If this is a boat the original poster is looking to buy there is not much chance the seller is going to agree to someone blasting the crapout of his hull.

    A sandsweep on the other hand might reveal some dull spots that need more attention but will still destroy the underwater paint system.

    First and foremost in looking at boats for sale should be audio gauging as it takes a lot less to patch up this than re antifouling or other repainting that is required after sand sweeping or blasting
  7. Oneiros, Sep 8, 2009
    #7
    Oneiros

    Oneiros Member

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    okey I thought he already purchased the boat. ok we audio gauging after we sandblast, it is easier to find the bad spot on the bottom
  8. bearhair, Sep 8, 2009
    #8
    bearhair

    bearhair New Member

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    I haven't bought it yet as we've been looking at several steel boats. Love what the Offshore could look like more than any other model of Roamer or other company. Problem is Offshore's seem very difficult to locate and this one being a few hours from home makes it very tempting. The topside needs complete rebuilding. That part doesn't scare me as woodworking over the winter months keeps the hands and mind busy. What I am afraid of is the hull. Since I am having a hard time finding someone with the eqipement and expertise to audio gauge and the hull is in definite need of at least a couple patches, I'm thinking of offering the owner same price he will get at the scrapyard since this is where it will probably go if no one buys her soon. First thing I would do is sandblast the hull to see just how bad she is and if not too bad go ahead and patch her up. Worst case, if she requires extensive re-plating I can take her to the scrapyard and recover what I paid. That way I would only be out the cost of hauling to the boatyard. Local scrapyard is buying at $90 per ton.
    Thoughts??
  9. Marmot, Sep 8, 2009
    #9
    Marmot

    Marmot Senior Member

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    Take a good look at the fuel fills on deck above the tanks (if that is where they are) water may leaking around them and running down the outside of the fill pipe then off the top of the tank and pooling underneath. If the tanks are steel it is very likely they are rotted out on top as well.

    As someone else mentioned, limber holes are critical in preventing water from collecting above stringers, make sure they are clear. Just like a wooden boat, a steel boat needs ventilation, make sure there is good air flow beneath the tanks to keep things dry.
  10. Charlie D, Nov 7, 2009
    #10
    Charlie D

    Charlie D New Member

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    Checking steel thickness

    One way to check the condition / thickness of steel plating: With the boat out of the water, crawl underneath with a hammer and a punch or screwdriver. Look for "suspicious" spots, small bubbles or pimples in the bottom paint, rust spots, things like that. Seldom do Roamers have rust under the cabin area, so concentrate on the aft area. Pound on it. If the punch / screwdriver bounces off, it is good. If it does not bounce, hit again, it may be like driving a nail into wood. Obviously this is somewhat destructive, but it is better than the alternative, not knowing about the rust-thru and having the boat sink when the last bit of rust finally gives out.

    I'd thought my boat was rust-free, the insurance company required an occasional survey. The surveyor used the above method, and found several bad spots, which he turned into holes. The boat was floating only because of bondo and many layers of bottom paint. I guess I'm thankful he found the bad spots. I repaired them, then he finished the survey and turned the results into the insurance company.

    This method is not as good as electronic audio sounding, it is something which anyone can do, with simple tools.