Location of Thru-Hull on Shallow Bilge

Discussion in 'Boat Design' started by Darkzillicon, Sep 12, 2023.

  1. Darkzillicon
    Joined: Jan 2023
    Posts: 159
    Likes: 55, Points: 28
    Location: Palm Beach

    Darkzillicon Senior Member

    Is there anywhere to get guidance on the location of thru hulls on the bottom of a boat? I know I need them where it is deepest at the transom as to not have the pumps run dry but I don't want to have an issue where the thru hulls are in the way and people step on them. Just wondering if there is a best practice or resource regarding locating them.

    19' Boat with a Design waterline of maybe 4" or so... wooden glass fiber/epoxy boat. maybe 3.5" of bilge height in the nearly flat transom.
     
  2. gonzo
    Joined: Aug 2002
    Posts: 17,480
    Likes: 2,023, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Are you saying that the through-hull fittings will protrude from the deck?
     
  3. Darkzillicon
    Joined: Jan 2023
    Posts: 159
    Likes: 55, Points: 28
    Location: Palm Beach

    Darkzillicon Senior Member

    Yes... they will so assuming I need to make a machinery area in the middle area of the rear of the boat. However I know sometimes when moving boats they use forklifts, and I don't know if there is an expected place for the thru hull...
     
  4. gonzo
    Joined: Aug 2002
    Posts: 17,480
    Likes: 2,023, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    What is the intake for?
     
  5. fallguy
    Joined: Dec 2016
    Posts: 8,042
    Likes: 1,823, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Boat Builder

    Don't you have a splashwell?
     
  6. Darkzillicon
    Joined: Jan 2023
    Posts: 159
    Likes: 55, Points: 28
    Location: Palm Beach

    Darkzillicon Senior Member

    not doing a splashwell. outboard bracket off the transom to improve the issues that DOGCALVARY was seeing with his sled.

    Also current transom is 24” so cutting down for a splashwell would make it more like 18” for mounting outboard or Jackplate so I think the Armstrong bracket is the way to go. Motor is 350 pounds.
     
    Last edited: Sep 13, 2023
  7. Darkzillicon
    Joined: Jan 2023
    Posts: 159
    Likes: 55, Points: 28
    Location: Palm Beach

    Darkzillicon Senior Member

    A/C unit 9K BTU ... 3/4" Thru Hull Scoop Strainer Groco. Probaby can Mount Filtration out of the way. just access to the thru hull and lever for shutting it off should be convenient.
     
  8. Darkzillicon
    Joined: Jan 2023
    Posts: 159
    Likes: 55, Points: 28
    Location: Palm Beach

    Darkzillicon Senior Member

    IMG_7487.jpeg I made a quick drawing of what I am thinking... I also did some spaceplanning last night and it seems like i need to build a machinery space low and amidships for the batteries 3x and the a/c unit (no generator) and the thru hull and strainer and associated plumbing.

    I guess my main question is is there a best practice or a place these are expected to be on the hull? I know quite often i see powerboats lifted with forklifts at a marina and it seems like the thru-hulls are more towards the center of the boat so that the forklift can lift on the outside near the chines. I could be wrong but that's my understanding.

    Yellow highlighted area is where thru hull would be amidships. Twin keels.
     

    Attached Files:

  9. gonzo
    Joined: Aug 2002
    Posts: 17,480
    Likes: 2,023, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    It looks like you are planning on keeping the boat at rack storage, so they will pick it up with a forklift. I would install the pickup at the transom like a transducer. It would also be easier to unclog.
     
  10. Darkzillicon
    Joined: Jan 2023
    Posts: 159
    Likes: 55, Points: 28
    Location: Palm Beach

    Darkzillicon Senior Member

    That was my first idea but due to the low height of the deck and the equipment in the middle I was concerned that you wouldn’t be able to walk in the back to handle lines. Or I’d have to raise the deck to protect the thru hull.

    What I do like about the idea is that the transom should be really low in the water with the weight so the pickup won't suck air with the nearly flat transom.
     

  11. fallguy
    Joined: Dec 2016
    Posts: 8,042
    Likes: 1,823, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Boat Builder

    Like I told DC. Splashwell also offers place for start batt and home for rigging.
     
    Last edited: Sep 13, 2023
    Darkzillicon likes this.
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.