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Which is better? Being on top or bottom?

  • Thread starter Thread starter Triskele
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Triskele

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Nov 16, 2012
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  1. OWNER - I own a Hatteras Yacht
Hatteras Model
43' DOUBLE CABIN (1970 - 1984)
Spent the last few nights reading through most of the threads on this forum about repairing/replacing the deck core and watching some youTube videos on same. Really found the thread "Galley Maid Windlass Removal" (repairs done by Dan Mapes) helpful and informative. Bought my 43 DCMY four years ago and at the time it surveyed for moisture on the deck and had soft spots around the bow pulpit, above the chain locker and down the starboard gunwale to the wing doors. It was my intention at the time of purchasing the boat, and still is, to have this breach repaired. The time has now arrived. Since I consider the return on my time from doing the repair myself to be of far greater value than most boat yards place on their time, I will be doing the work myself. (In other words, the $$$$ savings (and visceral experience...satisfaction) I will gain doing the work myself far exceeds the benefit of over paying a boat yard. There has been much back and forth on this forum about the pros/cons of DIY versus farming it out to ruthless mercenaries so I don't see the sense of going there (since you can probably guess my opinion). Suffice it to say, that I am doing it myself and don't wish to be persuaded otherwise. Having said that, I am well aware of the undertaking and my limitations. When the time comes, I will be happy to pay for a FAIR days work. Not the extortionist wages of the yards.

Now to the point. Where I am at at this stage is deciding whether to attack it from the bottom or the top. Based upon comments from his thread, and experience with his own project, Dan Mapes would vote for bottom. However, I have seen others who have taken it on from the top (pealed back the skin) on much bigger projects with success. And perhaps therein lies the difference. Correct me if I am wrong, but in Dan's case (sorry Dan, not picking on you) it was his first project and it was limited to the area forward the bulkhead and above the chain locker (an area that was relatively clear and approachable from the bottom and didn't require removing the headliner among other things). In other examples, it involved removing the core from an entire deck with an experienced crew (see Cap'n Bilgewater video on youTube...https://www.youtube.com/watch?v=QUk4O8YFun4). In that case, they went at it from the top.

After first reading through Dan's thread and following his progress and solutions to attacking from the bottom, I was a convert. However, after more thought and others input, I am not so sure that working from the bottom is right for my situation. Since, I also have issues along the gunwale and intend to repaint the deck, it probably makes sense to go in from the top on my project. Then as well, perhaps there is an arguement for a two pronged approach. Going in from the bottom to repair the area under the bow pulpit and over the rode locker, and also going in from the top to repair the area to the starboard wing under the walkway along the gunwale. Then finish up with a nice resurfacing of the deck. The problem with this is that if you are going to resurface the deck (always like answering my own questions) then shouldn't you go ahead and just remove the bow pulpit and finish that area from the top as well?

So here are my pros/cons of both approaches. Let me know what you think and anything else I may have left out in my analysis.

Bottoms Up:

Pros - don't have to remove the bow pulpit, don't need to resurface (won't be pulling up the outer skin), no need to repaint. For the inexperienced, any skrew ups are more easily corrected (hidden).

Cons - working in a rather tight and confined space, possibly messier for the inexperienced (think dripping epoxy...gravity works against you), need to build a "scaffold" to hold in place molds/jigs.


Top Down:

Pros - ease of access, hopefully less mess (can pour epoxy onto top of bottom layer (gravity works in your favor).

Cons - cutting into and pealing back the outer layer. The need to be skilled at laying fiber glass, fare, sand and repaint the outer layer. Have to remove the bow pulpit and perhaps other deck hardware. Although, I am under cover, in some cases, you will be exposed to the elements in which case you will have to work fast to avoid exposing the new core to moisture.


IMHO...for small jobs (under 2 sq ft), I would argue for drilling a few holes from the bottom (if accessible), vacuum the water/moisture out, let dry, seal and then go in from the top and syringe in a sealer such as "Git-Rot" or an epoxy to harden the "dried" core in place (without removing), seal it up and resurface the area. For medium jobs (defined as > 2 sq. ft., but < 5 or 6 sq.ft), working from the bottom seems to make sense if you have the access. For larger jobs (and on large vessels >36 ft?...after all this is a Hatteras Forum and there are very few Hatteras' under 36 feet that I am aware of), I don't see how you can get around not lifting the top skin and attacking the core depending on the amount of rot. (Full disclosure...again, this is my opinion based upon what I have learned to date through researching the subject. I have no experience to speak from.)

Thoughts? Feedback?


Look forward to hearing from you. Once I get started, will try to keep an online diary in this forum of my experience and progress.

Jay
 
Depends on how much repair you need to do and if it runs over any bulk heads. I did mine from the bottom. All mine was done inside the anchor locker (46C)
 

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Hard parts where, removing the windlass and putting fiberglass and resin on over my head.
 

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I think there's an important point about trapped moisture in this video. It reminds me of recently returning home after 10 days away, and finding the coffee grinds still soaking wet in the coffee maker.https://m.youtube.com/watch?v=c3dKSkPwP2MRegards, and best wishes Craig
 
Good Morning Jay, I have the same boat with the same issues. Vincent C was kind enough to share his pictures of doing the work from the top(again same boat). One of the big issues for me is support for the structure no matter which side you decide to work from. I find it much easier to support it from the bottom and work from the top. I plan to make as many of the cuts as I can in the non skid areas as I think it will be easier to hide. I need paint on my topside anyway so covering my work will be easier. My plan is to attack in 9 to 12 months. My areas were found during survey as well and have grown very little in 4 years. The jury is out at this point and if my pulpit has to come off but I am betting it will. Good luck and please keep us posted with pictures! Regards, Russ:cool:
 
I have done my fair share of fiberglass and coring work in the past. I find working upside down a real PITA. when laying in the core you need to be sure that you don't trap air into the layers. If your coring isn't sticking properly and falling down and not laying tight and flush it's a problem. Ive always used balsa which it little square blocks that are bound together with a mesh fabric to form a sheet. I have no knowledge of different coring materials and how they react. If you take a sheet of balsa and put it over a saw horse you can open up the blocks to apply the resin into all the balsa surfaces which is a must. After you apply your thickened fiberglass putty with a v-notch trowel you stick the two surfaces together. The problem is that the resin will start to drip out of the cracks And the balsa and will not stick very well to the putty upside down. If you work in small sections that will be your only option You will also have this problem when laying up the cloth or mat. From the top side it will be much easier to get the coring and mat down but shaping and fairing is labor intensive Most of the materials don't sand like drywall. Lol. And you will need to be careful that you don't have air bubbles and voids in your upper skin, over time this will cause surface failures. If you see white when grinding or shaping That is an indication of voids you need to grind them out. Also don't let the fiberglass hairs pop thu your final layer of resin. If I was doing the work I would work from the top on flat surfaces and from the underside if the fairing and shaping has a lot of curves and valleys. Sanding glass in tight curves and radiuses sucks most of that will be hand work and not machine It helps to hit it with 36 grit before it kicks rock hard. I buy all my stuff from mertons in Springfield ma. He is very informative and will answer all your questions and set you up with the best products for your project. The guy will spend lots of time walking you thru the process and how it relates to products and he ships nationwide. Hope this helps. It's just my prospective and others may think different. Good luck Have fun. Pete.
 
It seems to me that the only advantage to doing it from the bottom is not disturbing the deck upper surface. But if you take the upper deck skin out in one piece, you should be able to replace it with minimal damage and fair it back in, especially if that cut is in the nonskid. I would vote for doing it from the outside- the top.
 
Either way has its issues.

From below you have a lot of things to work around. From above you have a larger surface that needs to be faired and painted.

Ive seen the skin go back in and would not do that for large areas. It gets waves and then needs to be flattened out. Its easier to just repair and glass over with new, Grind flat and fair sometimes.

Either way I will be open with one thing you need to know.

Fiberglass will cause most people to itch badly.

Working in the heat with it is worse. Working in the cold with it raises issues with catalyst and cure time. Its not a DIY friendly project.
 
I would never go back to balsa. Indeed it was challenging from the bottom up. I can almost guarantee that the bottom laminate will give you some grief working from the top down. It doesn't have half the substance of the top side and you may find supporting it to be challenging. If you go from the top down make sure to have an arch in the supports. That would be the first thing to install. Get it in, and crank it into position some how so that it mates up with the existing laminate well. I am thinking some 1/4 inch ply "T" over an arched frame to spread things out. Since you saw my post you saw the frame and screw jacks I used. Working from the top something similar could work but all of the pads pressing up should be joined together (1/4 inch ply) to prevent shifting IMHO.
 
My wife is insistent top.



She just won't budge on that.
 
She said it's a lot less cleaning in the cabin afterwards.
 
Fiberglass and dust Bob.

Will you ever grow up?
 
Recently did the foredeck on my 1981 48MY. Deck was soft from pulpit to just aft of the hatch, about 10 feet from side to side. I did everything from below and am very happy with the results. Here is what I did:Removed windlass and pulpit.Made forms on two foot spacing of deck curvature for future reference.Removed headliner and all wood used to mount headliner in fwd stateroom.Cut through bottom layer of fiberglass and removed it exposing all the soft balsa core.Removed all soft core with a Fein tool and air chisel.Used 1" Coosa board to replace balsa.Cut Coosa into 12" wide strips 8' long. Scored upper side of Coosa 1/2" deep every 6" to improve the conformance with the deck curvature. Also drilled 3/8" holes through the Coosa in an 8" diagonal grid to indicate adequate resin flow when applying to the overhead.Used West System thickened with Cabosil and applied to underside with a trowel and filled the relief groves but not the holes. I used 10 scissor jacks to apply pressure and watched for resin to squeeze out of the holes indicating complete coverage. Allowed each strip to set for 24 hours. Used previously mentioned forms as a reference for deck shape when pressing Coosa into position.When all the Coosa was in place, i sanded all discontinuities flush and applied biaxial cloth. Then applied a layer of woven cloth. Also rebuilt pulpit. Replaced headliner in fwd stateroom as the final step.When complete the foredeck was solid. With a little over 1100 pounds of people on the foredeck, deflection measured from the inside of the fwd stateroom was less than 1/4".There is no denying this project was a major PITA. At 6'5" tall, it was a tight fit from below. It is messy and all safety equipment and adequate ventilation is a must.
 
Depends on how much repair you need to do and if it runs over any bulk heads. I did mine from the bottom. All mine was done inside the anchor locker (46C)

How heavy is the bow pulpit? Can one man handle it's removal?
 
Hard parts where, removing the windlass and putting fiberglass and resin on over my head.

What did you use for core?
 
Depends on how much repair you need to do and if it runs over any bulk heads. I did mine from the bottom. All mine was done inside the anchor locker (46C)

Did you use a sealant between the bow pulpit and deck? If so, what was it?
 
Good Morning Jay, I have the same boat with the same issues. Vincent C was kind enough to share his pictures of doing the work from the top(again same boat). One of the big issues for me is support for the structure no matter which side you decide to work from. I find it much easier to support it from the bottom and work from the top. I plan to make as many of the cuts as I can in the non skid areas as I think it will be easier to hide. I need paint on my topside anyway so covering my work will be easier. My plan is to attack in 9 to 12 months. My areas were found during survey as well and have grown very little in 4 years. The jury is out at this point and if my pulpit has to come off but I am betting it will. Good luck and please keep us posted with pictures! Regards, Russ:cool:

Hello Russ...

Thanks for your input to the thread. Sorry it has taken so long to follow up. Have been waylaid with changing engine fluids. I am curious about your concern about the need to support the structure even going in from the top. It was my understanding that by going in from the top, you "simply" lay in the new core where the old once was on top of the bottom glass. Do you feel the shape of the bottom glass will change without first supporting the new core until it has set up in the epoxy? I was thinking the bottom glass was plenty stiff and should retain its shape. Perhaps not...and thus the need for support. What core material are you considering? I am planning to use a 1088 marine grade plywood, but believe Roseburg A/B marine grade Douglas Fir would work just as well. Only concern I have with it is voids, but in a core ("sealed") environment it might be fine. Still mulling over this project. Can't decide whether it will be worth it to make the time and energy investment or be better off biting the bullet and selling the boat to someone who has the time, energy and know how. At this point, I feel I don't have enough information to proceed so I'm in the paralysis by analysis stage.
 

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