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External sea strainer fouling

Discussion in 'Post Yacht' started by baltimore bob, Apr 4, 2016.

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  1. baltimore bob

    baltimore bob Member

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    Post really loved using the external sea strainers and they seem to work fine except I've not yet found an antifoul that works for any length of time. The rest of the bottom will be clean as a whistle but the strainers look like you coated them with fertilizer! Any suggestions?
  2. Beau

    Beau Senior Member

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    Mine hold up pretty well with just bottom paint. Maybe try some of that newish prop coating?
  3. RT46

    RT46 Senior Member

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    x2 on bottom paint.
  4. Capt J

    Capt J Senior Member

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    I have them sand blasted, then hit them with a good aerosal primer and aerosal bottom paint inside and out and it seems to work really good.
  5. C team

    C team Senior Member

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    Egg Harbor used the same strainers. I use bottom paint and frequent running of the boat helps with them not building up and growth.
  6. bigg1069

    bigg1069 New Member

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    I use Pettit Hydro-coat eco it has worked better than anything else. Last year we did one with anti fouling primer and one with eco , the one with eco was like new. If you use the eco on the bottom as well you won't get that ugly green water line.
  7. Unavailable

    Unavailable New Member

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    3-4 coats of cold galv inside and out.
  8. mwwhit1

    mwwhit1 Senior Member

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    I have been using the zinc spray on them. Both sides. End of the season they still look pretty good. Though I move my boat often.
  9. Capt Ralph

    Capt Ralph Senior Member

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    I hope you kids don't mind a small side path; Seems a few external strainer users here.
    I was just talking with a surveyor last week about external strainers vs in-line strainers in the engine room.
    He just left a boat that had both. He was thinking of advising the new owner to remove the inside strainers.
    I had a feeling to remove the screens on the thru hull strainers and keep the interior ones.
    Thoughts?
  10. Capt J

    Capt J Senior Member

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    Keep both. Cabo (and others) used the screens and some customers added sea strainers. The screen strainers are pretty effective at keeping grass and stuff like that out. BUT, they don't allow sand and silt to drop out and this is where the swirling effect of the sea strainer shines. There is NO harm in having both. Generally on boats with sea strainers, they'll still have a slotted clamshell on the thru-hull.
  11. RT46

    RT46 Senior Member

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    I have both.
  12. baltimore bob

    baltimore bob Member

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    I've been using Pettit's Prop antifoul with good results (on the wheels). It is a zinc paint. You guys just using regular cold galvanize in a can? Any particular brand?
  13. Unavailable

    Unavailable New Member

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    I've been using CRC "Zinc it" on strainers rudders and tabs. I may want to try it on the props to this season. Prop speed worked well on the shafts, but not great on the wheels last year.. Although a butter knife and mask cleared the wheels in under 10 minutes. So I guess it worked.
  14. Capt J

    Capt J Senior Member

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    Prep is everything with prop speed. If you need to scrape stuff off prop speed, use only plastic putty knives. Prop speed is very soft and a butter knife or metal scraper will peel it right off. Also check and see if you have any galvanic corrosion and that all your running gear is bonded correctly. Galvanic corrosion will boil off any paint or coating you put on running gear.
  15. Unavailable

    Unavailable New Member

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    Grounding system is working good. The boat just received low use for two month with the family using it as home base. while we ran the contender to the canyon. What I was saying was I was not impressed with what I expected to be a lack of barnacle growth. Shafts were clean props were not. They popped right off and they were clear through September late November. When I was able to run it weekly. That being said the tabs strainers and rudders were clear as zinc exfoliates itself making it hard for anything to take a good foothold.
  16. Beau

    Beau Senior Member

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    Gotta send a diver down if you're going to sit dockside for 2 months in the NE.
  17. Unavailable

    Unavailable New Member

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    HA ha. I am the diver and with 2 feet of water below the props at low tide and zero visibility. I think Ill I'll be running this one a little more in June and July this season.
  18. Beau

    Beau Senior Member

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    That's more fun!
  19. Davidoc

    Davidoc Senior Member

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    Ralph, on the internal and external strainers, I have both. I agree with Cap J; keep them both. In the Bahamas we kick up a little sand once in a while and I find a crab or two on the inside as well. I use prop speed on the external when I have some of the kit left over from the rest of the running gear and it works pretty good if you keep them wiped off. Does anybody have any experience in So. Florida with the Pettit Hydro coat eco on the bottom?
  20. Capt Ralph

    Capt Ralph Senior Member

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    Update and new question.

    I did advise the Surveyor I was talking to to keep all equip intact. I expressed that I asked around and the veteran response was to keep them both. Thx for the responses.



    THEN, We started maintaining a 72' Hatteras. Large internal strainers for the A/C systems, but only external screens for the mains (C32s) and gen-sets (Cat 2.2s).
    The silt here in the Ortega river (JaxFL) has already made a mud bath out of the A/C strainers. in a few weeks while dockside.

    The mains and gen-sets will need some extra protection. This micro fine silt we have up here is a mess. Large wheels kick it up while maneuvering in even deeper docks and slips. You can see it blowing out the exhaust water.

    Is there such an internal strainer that would be any help here?