Bed Liner for protecting hull.

Discussion in 'Boat Modification Journal' started by ShilohRed, Aug 29, 2007.

  1. ShilohRed

    ShilohRed New Member

    Messages:
    4,339
    State:
    West Tn
    Take a quart of the bed liner roll on . And prep the front part of the hull, Then roll it on.
    I plan on trying it, On both of my boats as soon as I am able to get out and do it.
    If it works It should stand up to the boat ramps for a long time. And if you do tear it. Just out more over that spot.
    What do you think?
    Pete
     
  2. ShilohRed

    ShilohRed New Member

    Messages:
    4,339
    State:
    West Tn
    Forgot to add. That I would use tape to tape off the spot. And then roll the product inside the tape. Then after drying take the tape off. And your ready.
    I will do a write up of it when I get mine done. And take pictures.
    Pete
     

  3. Mr.T

    Mr.T Active Member

    Messages:
    2,554
    State:
    MO
    Are you thinking of using it in place of a keel-shield type of product, or coating the entire hull? That stuff is pretty draggy due to the texture - I'd expect it to slow your boat down quite a bit if used all over...
     
  4. BIG GEORGE

    BIG GEORGE New Member

    Messages:
    10,362
    State:
    JOISY
    I'm picturein ya usein this as a keel shield. I think ya may be on to somethin here. As far as the drag and speed loss. HMMMM! You may get nocked down a warp or two. LOL!
     
  5. smhmc6

    smhmc6 Member

    Messages:
    744
    State:
    Kansas
    Like Mr. T said, it will add alot of drag. Maybe you aren't as concerned about speed, but I imagine it will hurt fuel efficiency too.
     
  6. smhmc6

    smhmc6 Member

    Messages:
    744
    State:
    Kansas
    To add to my comments above, I put a little pencil to paper and came up with this. (This is if you are planning on doing the whole hull.) I don't know much about typical boat speeds and fuel economies... but lets say at full throttle you get 30 mph and 10 mpg. By coating the hull you add drag. Drag coefficient is inversely proportional to the square of your velocity. And fuel economy is inversely proportional to the coefficient of drag. Lets also say that the drag added by the bed liner slows you down by 10%. Thats going from 30 mph to 27 mph, not a big deal... but that decreases your fuel economy by somewhere around 20%. Thats going from 10mpg to 8mpg. If your speed is decreased by 15% (30 mph to 25.5 mph) then your fuel economy is decreased by around 28%... which is 10 mpg to 7.2 mpg. There is a lot more that goes into calculations like this... but I did a quick estimate using proportions and ratios.... maybe this will help in weighing the pro's and con's of this project.
     
  7. fishnfwl

    fishnfwl New Member

    Messages:
    3,334
    State:
    South Cent
    Well Pete, I would love to see and hear your findings, I have also thought about this, and speed and fuel are of no great concern to me considering that it will be on my river jon, and I just can't stand pulling to a ramp with the concrete and boulders that surround them, always scraping on the welds. I was planing on putting it inside seems it would be very easy to clean just spray out, and hooks would be no problem. I have also just got a piece of an old conveyor belt for the front, because my anchor has been banging up the front quit a bit, I use an anchor winch and it still hangs down just enough to put small dents and I was afraid it may hit wrong and crack a weld.... Unless anyone has used something different i'm gonna try this. Any thoughts?
     
  8. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    I don't think pete was refering to the whole hull as this is what he wrote


    Take a quart of the bed liner roll on . And prep the front part of the hull, Then roll it on

    This part is out of the water on plane any way. He wants to protect the front of the hull when beaching or docking on the ramp.
     
  9. smhmc6

    smhmc6 Member

    Messages:
    744
    State:
    Kansas
    You are right, just the front wont matter. It would probably do a great job of protecting the front. Its a good idea for that. I must have misread it though cause I wasn't sure if he meant the whole bottom or not. Anyway, I had a canoe once that I bought for setting a line every once in a while... but mostly just fishing in some ponds that had alot of brush and trees everywhere around so you couldn't cast good from the bank. It looked like someone put a thin layer of this stuff on the outside to protect the fiberglass better, man that thing was a chore to paddle around especially in current. Sorry for the confusion... but at least maybe if someone else is considering doing the whole thing they will see the downside of it.
     
  10. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    I knew he wouldn't do the whole thig cause he can't get down that far.:wink:

    And that war eagle is to heavy to turn over.
     
  11. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Actually friction is what you want to look at.
    A rough surface on the bottom of a boat at planing speed will have less boat to water friction then a slick well waxed hull. The rough surface creates air pockets and breaks the vacuum. It would be riding on a mixture of air and water.
    In theory the boat will gain speed. How much speed is the question of the day. I would venture to say very little based on the moderate speeds the hull sees. It would make a bigger difference running at high speed.

    Many race boat hulls do not have slick bottoms because of this.
    On a displacement or semi displacent hull this would work in the opposite direction creating drag.
    Air friction like on a race car and water friction like seen on a boat are two different animals. With the car you want to direct the air flowing over the car to the car's best advantage. You want the car to effectively cut the air.
    Water friction on a boat you want to break. The less actual water contact a boat makes with water the higher the speed potential. This is where the " running pad " came from and are highly engineered in size and shape relative to the hull.

    Its not the texture I would worry about. Its the weight of the stuff doing a whole boat. Weight and position of weight is the performance killer.

    I know this may seem nuts and it did to me at first.
    You have to forget comparing cars to boats in every facet imagineable.
    One operates in a 3D enviroment and the other in 2D.
     
  12. Mr.T

    Mr.T Active Member

    Messages:
    2,554
    State:
    MO
    Technical issues notwithstanding, I wonder how well you can get the bed liner material to stick to an aluminum hull, especially an old, oxidized aluminum hull?

    Guess you'd have to rough it up pretty good with a scotch-brite pad and then clean the heck out of it with denatured alcohol or laquer thinner. Probably end up spending more time in preparation than in applying the stuff.

    My boat has a factory sprayed-in liner and there are several spots where it's starting to come un-stuck.
     
  13. shadguts

    shadguts New Member

    Messages:
    564
    State:
    Tennessee
    A freind of mine bought a used fiberglass boat that had all bad carpet he ripped it out and put the bed liner all over the inside and I must say it looks great and easy to clean. Probably cheaper than carpet and glue. I dont think that coating the bottom of the boat would hurt the speed or fuel economy enough to tell unless the boat would do 100mph to start with . I dont have any scientific formula to use just my thinking.
     
  14. smhmc6

    smhmc6 Member

    Messages:
    744
    State:
    Kansas
    I also would be interested in how it sticks to aluminum. I guess it wouldn't be much different then putting in your truck bed. But I wonder if the prep work would remove the corrosion preventative layer and be bad news. I know in the aircraft industry they anodize aluminum (or something:big_smile:), I'm sure they do something of that sort to prevent corrosion on aluminum boats... if you scratch that layer off, you may be asking for trouble down the line.
     
  15. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    I can tell you how I prepped two 24 foot aluminum pontoons for a polyeurathane based coating.
    I used a 60 grit flap flap disk in a side grinder to abrade the surface.
    Then I sprayed the pontoons with self etching primer. Waited 5 minutes and hot coated the primer again with another coat.
    Then I rolled my coating on 22 coats thick ( about 2 mils thick ).

    It'll take a sandblaster to get it off.

    You have to careful be using a sidegrinder on boats.
    I didnt have to worry too much using a flap disk on my pontoons because they are .090 thick.
    You dont want to hang around too long in one neighborhood. Keep it moving.
     
  16. catfish kenny

    catfish kenny New Member

    Messages:
    6,064
    State:
    Iowa
    I have been thinking about using it on the inside to help seal the rivets on my ole lowe I chopped up....I havent committed to the idea fully but I am thinking it thru and considering it as a option.The boat has no leakige but I have cut a seat out etc.................... I dont think I would do the outside though
     
  17. ka_c4_boom

    ka_c4_boom New Member

    Messages:
    2,252
    State:
    Bedford,Ky
    iv got a cuz who used to fish bass tourneys he had a ranger boat that ran 72mph he had 3 feet of the underside in front of the motor sand blasted , gave it kind of a golf ball dimple and increased his speed to 76 mph

    as far as the bedliner it should work great to protect the hull inside or out

    iv got an alumicraft that the rivets have worked loose i hammered them back together and applied gorila glue to them they no longer leak

    infact i had a rivet pop out on the side wall on the water i stuck a cigerette butt in the hole and smeared gorila glue on it for a quick on the water fix , it held fine for the rest of the 8 hour tourny iv since placed a new rivet in the hole but i still carry the gorila glue on the boat
     
  18. ShilohRed

    ShilohRed New Member

    Messages:
    4,339
    State:
    West Tn
    Willard is right. Also theres so much of the front of my 20ft boat out of the water when on plane. That the stuff would not touch the water, That is until I hit a wave..
    I was thinking about 5ft that is all that will ever touch anything. Also it will and does stick to Aluminum hulls.
    I hope to get it done in a few weeks.
    And will take pics of the whole deal.
    Pete
     
  19. Little Mac

    Little Mac Active Member

    Messages:
    1,828
    State:
    NW Arkansa
    Pete, have you done it yet? I was gonna say dont leave that tape on there until it hardens, you wont get all the tape off and that will leave a very small gap that will catch air, water and eventually peel the whole thing off. In my opinion only!! Let it set up till it wont run, then pull the tape, Just my thoughts. Mac
     
  20. ShilohRed

    ShilohRed New Member

    Messages:
    4,339
    State:
    West Tn

    Jim I am still waiting until I can get around good. Still not able to get out and craw around under the boat yet.
    But yes I was going to take the tape off as soon as it would allow me to. Also I plan on tapering the sided down also.
    Just not sure when I will get around to it. but I hope in the next few weeks.
    Pete.