Blue Seas 31 Refit

Discussion in 'Downeast Projects and Boat Building' started by Turtleman, Sep 6, 2018.

  1. Turtleman

    Turtleman Member

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    I know the boat. I spoke with him just after buying my boat. He has the Palm Beach Sportsman Model.
     

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  2. CaseyMarie

    CaseyMarie Member

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    Thats a neat brochure, where did you find that? Did you happen to see one for the Out Island and any other models?

    Thanks
     
  3. Turtleman

    Turtleman Member

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    I have all the brochures. I bought the boat from the original owner and she still had all the brochures and marketing material in envelopes. I haven't had the chance to scan everything yet but I plan on scanning and posting what I have. I will do it on a dedicated thread. The cool thing is she also gave me a copy of an offshore magazine which ran an article on the Blue Sea 31. My particular Boat was one of 2 boats the author of the article took a ride on so the article includes pictures of my boat.

    I have to include I like your list of boats, I have a 17 BW newport and a 15 BW classic as well as 2 WM inflatables, as well as a bunch of other "personal" boats. My wife calls me a boat hoarder.
     
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  4. CaseyMarie

    CaseyMarie Member

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    I look forward to seeing your brochure scans. wow, that's so cool about the offshore magazine. I would like to get my hands on a copy. Can you tell me what issue/date the magazine is?

    It sounds like we have very similar tastes in boats. Great minds...
     
  5. Turtleman

    Turtleman Member

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    I was motivated to scan the Offshore Article. I am trying to upload my scans but I have some resizing to do. Here is a teaser from the Offshore, Rocknak's Ad for the Blue Sea 31.
     

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  6. Turtleman

    Turtleman Member

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    Update time, been taking care of my wife's to do list, its the compromise for the project in the first place.

    I had some free time due to the usual New England October rain to start on the removed diesel tanks. After 30 years, and while the engine was out of the boat, It was decided it would be best to take them out and inspect them and if the tanks passed I would clean, polish and replace all the fittings and install inspection ports.

    After the Engine was removed by my yard, the tanks came out. Overall the two 100 gallon aluminum tanks seem to have made out OK. The yard pulled 30 gallons out of one and 70 out of the other. I picked the tanks up and brought them home and got to power-washing. I was able to eyeball into the tanks sending unit holes. The remaining fuel looked clean with no contamination or algae growth in both tanks. So,this past weekend, while my house and yard was drying out, I pulled a tank up to the work shop (garage) and pulled the fittings and started polishing the outside of the first tank. Polishing by the way of 220 grit with my orbital sander.

    Ok, I did do some Youtube research on polishing aluminum. Anyway, started with 220 to get the 30 years of age off the tank.. I sanded the whole tank off. After this I thought I had some in between grit to no avail so i went into 1000 grit, 1500, 2000,then 3000 I bought for the polishing. I decided to test the process on the bottom of this first tank. After about half hour, I was quite surprised to get the bottom to start showing a clear reflection.

    The end of the day came sooner than expected so I cleaned up, grabbed a beer and inspected my work on the tank. I found pitting had obviously started on the top of this tank from standing moisture. The question I now have is at what point should one be concerned about the aluminum pitting. I have been informed that you can seal a aluminum. However, I do have concern with the second tank. While I was powerwashing the tanks,the bottom of this second tank appeared quite pitted in two spots. It appears that moisture concentrated under one tank, which lead to a higher pitting in these spots.

    My plan for the tanks is that I get both polished up and re-inpect.
     

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  7. Keelboater

    Keelboater Captain

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    Generally speaking, aluminum tanks are usually 1/8" thick. If the tanks are in overall good condition with just a few deep pits, you can repair the pitted area by TIG welding. I don't understand why you are polishing the tanks though. I understand the nature of a polished surface vs. a mill finish when it comes to corrosion, but most people just clean them up and epoxy barrier coat them. That does not let any standing water create future pits in the aluminum. If pitting has taken it's toll, just replace them with new tanks and don't look back.
     
  8. Toolate

    Toolate Captain

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    And I would go for some tape over the holes in the tank while working to keep it as clean as possible. Also, will you come polish my tank when youa re done? Who doesn’t like polished metal!? Agree with Keelboater though if you are going to re-use the epoxy barrier coat is the way to go (color of your choice) in which case sanding with 220 to clean them up is prob all you need then a good solvent wash. I think an air test would be in order before getting too committed and after the sanding. I think its just 1-2 psi though not sure.
     
  9. El Mar

    El Mar Captain

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    Wouldn't polishing actually remove metal causing the tank to fail sooner?

    Coat it as said before, main thing keep it dry and out of standing water.
     
  10. Turtleman

    Turtleman Member

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    If the tanks are in overall good condition with just a few deep pits, you can repair the pitted area by TIG welding. I don't understand why you are polishing the tanks though. I understand the nature of a polished surface vs. a mill finish when it comes to corrosion, but most people just clean them up and epoxy barrier coat them. That does not let any standing water create future pits in the aluminum.

    I was able to check the second tank yesterday and found a couple deep pits on the bottom where it appears water pooled under the tank. I have attached a couple pictures. So I think this tank will have to be repaired. Otherwise the overall condition of both tanks is very good. It was suggested I could epoxy the tanks. I had not thought of just using epoxy barrier coat. If anyone has done this I would like to hear how its working out.

    As far as polishing my thought is if I can get the natural surface cleaned and protected I would get away from coating them with something else which may fail in the future. It just seems painted metal and salt water don't get along for very long.

    I am also going to look into seating the tanks on thin runners to keep them from full contact with the fiberglass shelf they sit on. I was doing some trim work on the house with PVC and I now have several strips of 1/8 PVC about 2 inched wide. The thought is to place the tanks on these 1/8 for a small airspace, Any thoughts?

    I also plan on installing 2-8 inch seabuilt access ports in each tank. Cutting these in will allow me to give the tanks a good inside cleaning before the re-install.

    Attached is a picture of the polished tank bottom and the other untouched tank with the pitting. 20181031_082114 resize.jpg 20181031_082159 resize.jpg 20181031_082240 resize.jpg 20181031_082218 resize.jpg 20181031_082222 resize.jpg
     
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  11. Frank

    Frank Senior Member

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    Just for piece of mind replace the tanks while you have the boat all apart. I would hate to see you get a leak a year from now and have to yank everything all over again.
     
  12. Toolate

    Toolate Captain

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    I am onboard with this after looking at the pics you posted- 99% of the tank material could be good but all it takes is one little spot. The cost would be a fraction of the cost to replace one later after everything is put back together. Epoxy coating tanks has been going on for a long time and its not just a paint. This keeps all moisture from getting to the aluminum which is what causes the oxidation in the first place and the epoxy will not peel off or anything like that over time. Last 2 boats I did I put new tanks in and epoxy barrier coated them (2000E from Interlux) when new with an extra coat or 2 where the tank would sit on its beds.

    Tank mfgr with pics of epoxy coated tanks they made on their website. Custom Aluminum Marine Fuel Tanks - SP Tanks
     
  13. MASTERENEGADE

    MASTERENEGADE Captain

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    Just my 2 cents
    I understand it is easy for us all to say just replace the tanks with new ones, its not our check book or time and labor. But as a candidate for a new tank as we speak on my 24' privateer which will involve cutting the deck and replacing probably the entire floor during the project, as well as someone who went through this with a 35'JC before as well. If there is any pitting at all, financially and labor wise it makes no sense to consider dropping the old tanks back in if there is any pitting. Thats how it started on the top of my current tank which created 4 holes around the pick up. God only know how many more I will find when I rip the whole tank out of the boat..
    For you and your boats future I really do hope you decide to replace the tanks all in all.
     
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  14. Keelboater

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    [​IMG]


    A few pits are repairable but wide spread pitting like this always means a new replacement tank. This kind of rash just keeps getting worse. Lathering it with epoxy is just adding a band aide and is not a cure. I agree with the above comments. The good news is that you can measure each tank and make a sketch of exactly what you want the new ones to look like.
    I highly recommend Luther's Welding in Bristol R.I. Not only are their fuel tanks A+ quality, but they also have a delivery van that makes life very convenient for you. That said, if you pick them up in person you will be in for somewhat of a treat when you see where their shop is located. Give them a call at 401-253-5550 and ask for Bud. As for barrier coating a new tank before installing it, I highly recommend it if you want them to last a very long time. The barrier coat fully prevents pitting from water contact. Just give them a good sanding to provide some tooth for the epoxy and be sure to wipe them down good with acetone prior to coating. You will be glad you went this route in the end.
     
  15. Blitzen

    Blitzen Captain

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    Also Keep in mind that the water on the outside can cause pitting and will do the same on the inside and sometimes worse. Before doing anything to the outside of the tank I would be looking at the low point inside the tank for pitting where water might sit. We had several tanks fail that looked perfectly fine on the outside but failed from a small amount of water inside the tank.
     
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  16. ARC

    ARC Senior Member

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    Poly tanks cant be that expensive. You may spend close to that on repair plus coating. Easy to install and give you 20 years. + if you sell , it is one less thing on the no go list.
     
    ARC,
  17. MASTERENEGADE

    MASTERENEGADE Captain

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    dumb question. Can poly tanks be used for under deck gasoline capacity? I dont mean to derail the thread
     
  18. ARC

    ARC Senior Member

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    they are on some high end CC's
     
    ARC,
  19. Toolate

    Toolate Captain

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    Yes. Had the fill neck break off mine last year though... one bad one of maybe 8 that I have installed in various boats in my life so pretty good odds lol. I would go aluminum with epoxy for gas myself.
     
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  20. Turtleman

    Turtleman Member

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    Thank you for comments. Even though the tanks can be installed easily with no cutting up the decks the engine definitely need to be out. So since I have the Engine bay empty I will be taking the advice of forum to measure the tanks up and get a quote on new tanks.
    I do have a general question if anyone can answer. The fuel pickup and the fuel return are at different end of the tank. Is there any reason for this or can the fitting be at the same end?
     

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