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  • Building bulkeds and tank coffins

    Well my first attempt to build a bulked and tank coffin for a 17 standard are about to begin.I have no known knowledge of glass work other than repairing my surfboards.The bilge setup would be involved aswell.Cleared all the fuel soaked foam(TIME BOMB) on both sides of the center stinger.Cut the existing tub out of the cap,noticed there was nothing to block water from entering the forward part of the hull between the stringers from the drain plug.Didn't like that idea so I wanted to build a bulked to allow the bilge float to turn the pump on before the whole hull was flooded.

    Question # 1.Should a bulked be built in a 17 standard,So the drain hole water cannot reach the forward portion of the hull?

    Question # 2.What is the right way to go about this?

    Question # 3.What is the best material combonation for this application ?(oz glass,type resin,Marine ply,how many layers,etc.......?? and materials to seal and paint the bilge?

    Quetion # 4. the best location in terms of distance from aft ?

    Any advice would be greatly appreciated and welcomed,If only to respond to a portion of any question.

    Thanks a million!

    VBMAKO17
    1980 Mako17 Standard, 115 Yamaha 2 stroke[br]1981 Mako224 200 johnson 2 stroke Virginia Beach,Va

  • #2
    1. You must allow drainage from the forward bilge this can be done by putting a 1" pvc tubing through the lower apex of the bulkheads fore and aft of the tank pod, allowing the water to pass through without soaking your tank foaming.

    3. I would advise GP polyester resin with alternating layers of mat and roving. You could use marine ply or higher tech (lighter) cores for the bulkheads. If you do go with another type of coring such as PVC foam, why not use 1708 biaxial. Gelcoat for final coating. (note: all of these boats are built with GP polyester resin-why would you want to introduce epoxy into the matrix- you really don't)
    Richard[br]Miami[br]Pearson Flyer 30

    Comment


    • #3
      These boats are built with polyestr resin, but when doing repairs or additions to an already cured polyester resin surface you cannot achieve any chemical bonding to that surface. Its all a secondary or mechanical bond to a rough sanded (prepared) surface.

      Many of us like epoxy resin because it has a secondary bond strength that is exponentially higher than polyester resin. But, if used properly polyester resin is okay, just not my preference. I can sleep well at night knowing that the strongest bond I could have achieved is in my repair/addition. But thats just me.

      When using wood for a core material, epoxy penetrates and encapsulates the wood extremely well. There is nothing beter for laminating wood.

      As far as I'm concerned, the only drawback to using epoxy is that I cannot slap gelcoat onto it without waiting for it to cure and then prepping it properly.

      If I were going to use something other than epoxy resin, it would be vinylester resin.
      Slidell, LA 1993 Mako 261B - Temperance

      Comment


      • #4
        Rich Mako ,In the 17, there is no front bilge.So when building bulkeds are drain holes,tubes mandatory fore and aft of the fuel cell for a proper install? I have seen that on the 21,22ftr, not the 17 though?

        Ringleader,What is the process and prep of gelcoating epoxy? And does it turn out as good as polyester? Also,is vynylester a good product for sealing the bilge area? Last, where can I get the foam to refill all the foam I took out, what density,brand etc...?

        Thanks! vbmako17
        1980 Mako17 Standard, 115 Yamaha 2 stroke[br]1981 Mako224 200 johnson 2 stroke Virginia Beach,Va

        Comment


        • #5
          I think that I misunderstood your situation. Your boat has a tank pod (coffin) that you removed (why? was it damaged?) and now you are going to replace it with bulkheads and side partitions. I think that is what I read.

          Well, if it was my boat and I had an abundance of time and space, I would repair or remake the pod and install it as the factory originally had it. I would most likely remove the entire cap/liner/deck and glass the molded piece flush and while there replace the coring in the deck and floor. That is just the way I do things. I am a stickler that the finished job look stock. That is me, you could repair replace the pod and glass onto the existing deck flange as you see fit.

          I would avoid the bulkhead plan as the boat wasn't engineered that way. It would create hard spots and over the years the boat would start to look like a starved dock, with the bulkheads like the pooch's ribs.

          Make sure there is adequate thickness of foam between the hull and the underside of the pod. The pod will abraid the inner hull skin otherwise.

          As to the question of the foam being open to water from the aft bilge area. Well, I agree that the foam should be isolated from water, but evidently, the engineers at Mako don't mind. Look at the rod holders on the older 22. Funnels water right onto the foam. My 'new' 228 has exposed foam on the aft inner hullsides outside of the livewells. I can't crane my head under the deck but I'd bet there is exposed foam forward of the below deck livewell, also.

          Either way don't leave out the long PVC tube that allows water from your anchor locker to bypass the foam back to the aft drain plug and good luck with the project!
          Richard[br]Miami[br]Pearson Flyer 30

          Comment


          • #6
            My plan is to reinstall the original pod and build an aft bulked after replacing all of the foam that was saturated with fuel from a 25 yr old leaking tank.The foam foreward the fuel cell was dry and there is no 1" pvc drain running from the anchor locker.just don't want that much water in the hull before the bilge float kicks on.That is the thougt behind the bulked
            1980 Mako17 Standard, 115 Yamaha 2 stroke[br]1981 Mako224 200 johnson 2 stroke Virginia Beach,Va

            Comment


            • #7
              VB Mako,

              Saw the pictures of your boat on the other thread. Your boat is much cleaner than I imagined. Doesn't look like it calls for anything so drastic. Did you cut the pod out? Why?
              Richard[br]Miami[br]Pearson Flyer 30

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              • #8
                I didn't cut the pod on the weight bearing section of the originally installed cap.I made my cut on the thin part about 3 1/2" down from the hatch rest.The leaking fuel tank had saturated the foam underneath the pod and all around between the stringers. When I replace the tank(supposed to get it tommorrow),dont want any false fuel fumes or fuel in the bilge.I'm scared of the thought of cig,spark etc... The only way to get it out was to cut the pod out.Where can I get the foam to replace what I've dug out,minus the h2o
                1980 Mako17 Standard, 115 Yamaha 2 stroke[br]1981 Mako224 200 johnson 2 stroke Virginia Beach,Va

                Comment


                • #9
                  I understand. Sometimes you must break some eggs to make an omlette.

                  I get my supplies from Joe's Auto Marine-Best prices. They are in Ft. Lauderdale. I don't know about your area. 2 part foam is readily available. The only question is price. See if there is a boat builder in your area and let him sell you some. He'll probly wholesale it too you.
                  Richard[br]Miami[br]Pearson Flyer 30

                  Comment


                  • #10
                    [:x)] Any teachers out there?
                    1980 Mako17 Standard, 115 Yamaha 2 stroke[br]1981 Mako224 200 johnson 2 stroke Virginia Beach,Va

                    Comment


                    • #11
                      quote:


                      Originally posted by Rich Mako 228


                      Well, if it was my boat and I had an abundance of time and space, I would repair or remake the pod and install it as the factory originally had it. I would most likely remove the entire cap/liner/deck and glass the molded piece flush and while there replace the coring in the deck and floor. That is just the way I do things. I am a stickler that the finished job look stock. That is me, you could repair replace the pod and glass onto the existing deck flange as you see fit.



                      I agree with being a stickler for details, but it is impossible to remove the inner liner from these Mako boats. I talked with several guys who tried to remove the innerliner from the hull and ruined the boats in the process. There is just too much foam holding these boats together. Imagine how hard it is to get a fuel tank out of the foam (in many cases). Now try getting a whole inner liner off the boat.

                      You can make a pod and glass it to the underside of the deck. You'd have to glass in some cleats first that extend down about 12" or so and then glass your pod to the cleats. It won't be beautifully molded with gelcoat, but it will work... Once the lid is on the fuel tank compartments, nobody will every know.

                      Prepping Epoxy.

                      1. let epoxy laminates fully cure (several days)

                      2. wash with water and a scotch brite pad (to remove amine blush)

                      3. Let thoroughly dry and wipe with acetone several times

                      4. Thoroughly sand the surface with 180 grit

                      5. Dust, tack rag, and acetone wipe.
                      Slidell, LA 1993 Mako 261B - Temperance

                      Comment


                      • #12
                        Ring to save the day,

                        after thinking every which way to do this,logic took over and bingo you nailed it! I spent much of today clearing all the foam up under the backside perimeter of the pod.I'm going to bolt the cleat hangers with stainless bolts to the flange that I reinforced with epoxy encapsulated 1x3's to the backside of the flange I did not cut from the deck when I removed the pod.,and lay down a bed of two part foam the same height as the bottom of the pod.If I pour to much I can just trim it horizontaly to height with a hack saw blade.This should allow the support needed to realign the pod.I will then spot weld the pod to it's mate with 5 minute epoxy and reglass the inside of the pod where the tank goes.Once I pour the rest of the foam,I should have enough support all around to sand out and regelcoat.I'm crossing my fingers but I think I can make it look as though It was never touched.Then again this is my first time doing this.The trick is not to pour to much foam so as to break the glass thats on the inside.The tank also has anchor tabs which is also why I reinforced the flanges.Should be as strong as it was before.

                        Constructive critism is very welcomed. Let me know if I've missed somthing.Besides,theres no way I'm gonna think about tearing that cap off after reading some of the other threads.

                        THIS IS THE SHORT VERSION RIGHT ?[][][]
                        1980 Mako17 Standard, 115 Yamaha 2 stroke[br]1981 Mako224 200 johnson 2 stroke Virginia Beach,Va

                        Comment


                        • #13
                          You can buy the same foam in sheets that can be cut to fit under the pod even just as spacers till you get the pod secured in place. Then the pouring can be done to runout the cavity. Same technique when installing the tank. As far as using poly over epoxy, they say it can't be done. But I hear that people are doing it. Haven't tried that myself.

                          I have pulled one piece deck/liner/caps out as one piece from several boats, one being an old Mako Perdue. You have to realize that when they get to the point of being ready for this job, either the boat is old and the foam bond is somewhat softened, and/or repairers have done jobs like deck replacements and foam is secondary bonded or voided. The deck lifts off with brut force and a strategically placed cut on the transom liner. I've never tried this to a newer boat but could imagine that the foam may not want to let go.
                          Richard[br]Miami[br]Pearson Flyer 30

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