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Drilling the hull

#1  When drilling holes in the hull/transom for screws, mounting trim tabs in my case, would it be ideal to drill the holes, then hit them with a countersink to break over the sharp edge?  I'm thinking this would reduce or eliminate spider cracks radiating out of the hole.  Or, is it not necessary?

#2  "Marine Sealant"...  Is this just 100% silicone, or is there something unique about it?  Just wanting to see if I need to make a trip for something special.

Any other tips are welcome!  I'm a wee bit OCD and don't mind going extreme to do it right.

Thanks!

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    212rowboat212rowboat Member Posts: 2,591 ✭✭✭✭✭
    I feel your pain, as cousin' billy would say....

    For at least ten minutes I stared at my marks on the transom, carefully measured and drawn- then measured again.... x at least 10, in order to buy me more time before doing the inevitable... 

    then I held the drill bit to the marks, finger on trigger of drill, but my finger disobeyed my brains orders and just wouldn't squeeze... so I do what I always do in circumstances like these, and used it as an excuse to pour beer on it... which had the side affect of questioning my judgement under the influence, which caused a ten minute job to extend over two days... the next day, there I sat.... drill in hand bit aligned to marks.....

    in the end, my finger relented and the remaining five holes took less than a minute....


    so.. anyway:  mark your drill bit.. use tape, paint, whatever- choose how deep you're going and don't go beyond that.  use marine sealant.. 4200 by 3M is the item of choice- 5200 is too much, and those brackets will become permanent fixtures on your transom or there will be huge chunks of fiberglass missing from where they once were... fill the hole with the 4200, and dip the screw in it- wipe excess away.  

    No need to attempt countersinking... the bolts should be an acorn bottom flat top fitting nicely against the trim tab brackets with only the shaft of the screw inside the taps you just created.  
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    raybo3raybo3 Administrator Posts: 5,468 admin
    Rule of thumb.........5200 below water line......4200 above water line.......... The choice is yours.... Good luck and keep us posted.....
    2002 342 Fiesta Vee PC Point Of Pines YC Revere MA. popyc.org     raybo3@live.com
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    jme097jme097 Member Posts: 1,224 ✭✭✭
    I have been told by a couple of marine mechanics to use a high RPM drill (over 2,000 RPM and to drill it in reverse. When I installed my under water lights on my last boat I did not drill them in reserve and didn't have any issues. I did however use an impact drill motor that was at about 2,00 RPM's. Was told that the faster it spins the less likely there is for a chance for the gelcoat to crack/chip. I don't know how accurate that is. I used 4200 3M. They say it is "Semi-Permanent" but I tried removing my underwater lights on my last boat before I sold it and I couldn't even make head way when trying to remove them. You will be safe if you use 4200 or 5200 for sure. 
    Boat Name: Knot A Worry
    2007 280 Rinker Express 6.2L B3
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    Cableguy GregCableguy Greg Member Posts: 5,016 ✭✭✭✭✭
    raybo3 said:
    Rule of thumb.........5200 below water line......4200 above water line.......... The choice is yours.... Good luck and keep us posted.....
    If you want permanent below or above the waterline, use 5200. 4200 or 4000 can be used below the waterline as well. I would use 4200 for your application.
    2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA "Blue Ayes"
    Go Steelers!!!
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    NRathNRath Member Posts: 135 ✭✭
    Good tips, thanks!  I would like the option to remove as I foresee the potential for helm adjustable tabs in a year or so.  Obviously, these are below water, but mine is trailered and won't be slipped, so they won't be submerged for weeks/months on end.
    So, option to remove leaves me at 4200??
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    Cableguy GregCableguy Greg Member Posts: 5,016 ✭✭✭✭✭
    NRath said:
    Good tips, thanks!  I would like the option to remove as I foresee the potential for helm adjustable tabs in a year or so.  Obviously, these are below water, but mine is trailered and won't be slipped, so they won't be submerged for weeks/months on end.
    So, option to remove leaves me at 4200??
    Yes, 4200.
    2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA "Blue Ayes"
    Go Steelers!!!
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    Michael TMichael T Member Posts: 7,227 ✭✭✭✭✭

    When drilling into gel coat I always use a counter sink bit made for gel coat or a spin the "normal" bit in reverse. Holes in gel coat that have not been counter sunk have a high probability of spider cracking. I agree that allowing a variable speed drill to rotate the bit too slowly can cause chunks of material , in this case gel coat, to be broken loose as a sharp bit with bite in and pull up at slow speeds.  1000 +/- rpm with a light but steady touch has always worked for me. I have seen too many cracked holes to count from a lack of counter sinking and overthigtening.

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    NRathNRath Member Posts: 135 ✭✭
    10-4, I can handle it.  I don't have a fiberglass specific c'sink, but I'd have a pretty fine 5 flute one that should do the trick.
    We're off to the races!
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    rasburyrasbury Member Posts: 8,282 ✭✭✭✭✭
    212, that's some funny, well, stuff. Got a chuckle. There are drill bits that have a counter sink built into the bit it self. I would think that a good way to do it and it's all tidy in one shot.
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    rasburyrasbury Member Posts: 8,282 ✭✭✭✭✭
    great tips Al...
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    NRathNRath Member Posts: 135 ✭✭
    I finally got the tabs mounted over the weekend.  The first time out working on them, I convinced myself I didn't have time to finish the job, so I waited to start.  A.k.a, I was putting off breaking out the drill!!  lol.

    Once committed, it wasn't a bad job.  More time was spent marking the holes and confirming symmetry than was spent with the drill spinning.  The speedo sensor caused some headache on the starboard side.  As-is, its dead against the trimtab, actually had to file off a little plastic.

    Here's an example of screws without a countersink, and how not to work on a boat hull.  There are actually 3 holes at the btm left mount point, one is filled with sealant.  Given the dash has a speedo, I assume this was factory work: 


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    NRathNRath Member Posts: 135 ✭✭
    I'm liking this kind of hole a little better:


    Thanks for the heads up on countersinking!  These were #14 screws, so I started with a center punch, then 1/8" pilot hole, countersunk that, then went to ???.  Nauticus said to use a 7/32, but that was almost a clearance hole, so I went a little smaller.
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    NRathNRath Member Posts: 135 ✭✭
    Looking at the final pic, it looks like the actuators aren't sitting at the same height.  I made a cardboard jig to set the angle of the tab with reference to the bottom of the hull, so I am pretty confident they are both sitting 25º down, pretty accurately.  I'll have to see what's going on with this when I get a minute.  Maybe the tape is off where the color split is causing it to look different.

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    Michael TMichael T Member Posts: 7,227 ✭✭✭✭✭

    Beautiful job NR! :-)  Great pics of how not to (by someone else) and how to (your job) prep the holes.

    I remember the first time we  put "big" holes in the hull of one of my boats - for through hull exhausts. It was done on a 1994 Rinker 190 in 1998. I had put a 390 HP 383 in it and was installing 4" Corsa Captain's Call switchable through hull exhausts. That was my first experience drilling a big hole in a Rinker hull. A marina tech at the dealer and I did the job. We must have measured it 10 times LOL.  There were a crowd of guys around - NO one who saw the result ever doubted how Rinker makes a hull!!!!! We burned out two sets of brushes in a 1 3/4 HP shop drill. The darned drill was smoking! The dealer asked to keep one of the plugs to display to customers. Those Rinker transoms are way beyond strong. I drilled a lot of big holes in hulls since then helping other guys but I have never seen a layup like in that low priced Rinker hull - even in boats costing 5 times its price. THAT sealed the deal for me regarding the toughness of Rinkers. I just received an e.mail from the third owner of that boat a few days ago and that hull is still going strong.....a hull designed for either the standard 3.0 L or the "big" 4.3 LX  has ben handling all that torque and HP for 18 years. That's a Rinker.

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    mvnmvn Member, Moderator Posts: 744 mod
    edited August 2015
    NRath said:
    Looking at the final pic, it looks like the actuators aren't sitting at the same height.  I made a cardboard jig to set the angle of the tab with reference to the bottom of the hull, so I am pretty confident they are both sitting 25º down, pretty accurately.  I'll have to see what's going on with this when I get a minute.  Maybe the tape is off where the color split is causing it to look different.


     
    I noticed on my previous 192 that the black/off white color split was way off; might be the same in your case.  It's too hard to tell from the photo.

    For even better performance, you may want to look at a cupped stainless prop.

    Great job though....you'll love the tabs.

    Mark
    Good,  fast,  cheap.... pick two. 
    2019 MTX20 Extreme

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    Handymans342Handymans342 Member Posts: 10,375 ✭✭✭✭✭
    I see a three blade prop then a 4 blade. Did you swap out?
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    mvnmvn Member, Moderator Posts: 744 mod
    I see a three blade prop then a 4 blade. Did you swap out?
    2 different boats, if you're referring to the post above. 

    Mark
    Good,  fast,  cheap.... pick two. 
    2019 MTX20 Extreme

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    raybo3raybo3 Administrator Posts: 5,468 admin

    I see a three blade prop then a 4 blade. Did you swap out?

    Wow Handy I could say alot about this but I will be nice. Maybe you inhaled to much diesel fumes............lol
    2002 342 Fiesta Vee PC Point Of Pines YC Revere MA. popyc.org     raybo3@live.com
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    NRathNRath Member Posts: 135 ✭✭
    MVN- yeah, I can see the uneven look in yours, too.

    Being a newbie, I didn't want to dig too deep for a prop until I was comfortable with what I wanted.  The Solas 4 pedal AL was only $120 shipped.  I'm usually not one to replace something until it's broke, so we'll see how it goes.  I read that "cupped" is a feature that's on the trailing edge of the prop.  A smallish 1/4 - 1/2" of the prop flaring upward increasing the angle of the pedal.  The stock V-P 3 pedal and the new Solas both have this.  I should do a little more reading on this.

    Interestingly, almost every detail of the V-P prop is identical to the Solas.  Are they manufactured by Solas for V-P?
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    NRathNRath Member Posts: 135 ✭✭
    Perspective on the tabs is over here
    http://rinkerboats.vanillaforums.com/discussion/3947/time-to-plane#latest

    The short story is 2 thumbs up!
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    NRathNRath Member Posts: 135 ✭✭
    Perspective on the tabs is over here
    http://rinkerboats.vanillaforums.com/discussion/3947/time-to-plane#latest

    The short story is 2 thumbs up!
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