The "NANCY G" a surfboat /lifeboat to motorsailer conversion build in progress

Discussion in 'Boatbuilding' started by viking north, Feb 11, 2011.

  1. hoytedow
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    hoytedow Wood Butcher

    I see the shed color matches your anchor. Good luck with the build. Estimated completion date?
     
  2. viking north
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    viking north VINLAND

    Hoyte -- timing is everything -- She should go into the water in two years -- the year of my final house morgage payment, the year of my 70th. birthday, the year of my next winter holiday Stateside, -- I work well under pressure, at least thats what I keep telling myself --:)
     
  3. viking north
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    viking north VINLAND

    Well here are the choices: The top design is nixed because it involves cutting into the existing keel. The toss up is between the middle long keel/skeg combo and the full keel design at the bottom. While i like the strength and build simplicity of the full keel I still have that yearning to tweak the performance as much as possible with the keel/skeg combo. Having seen both professionally layed out doesn't make it any easier. I've decided to let it evolve thru the degree of difficulity in mating with the existing keel. In other words I know it will be easy to build the full keel version,but once again I'm gonna give the keel/skeg a go and if I have difficulty of attachment or doubt of it 's strength, it would be a simple matter to revert. Afterall the customer in this case is in full agreement. :) I am presently working in the bow area of the existing keel blending it to meet where the lower leading section of the new keel begins. Photos next post.
     

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  4. viking north
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    viking north VINLAND

    Building the male keel mold up forward, I am blending in the wide origional keel using the same system as on my previous trial runs. That is, using what i call a taper section between the origional and the new keel. This increases the dept of the origional keel by some 3 and 1/2 to 4 inches from where it attaches to the lower end of the stainless bow cap back to where the new main keel begins. Beyond that there will be some but much less cross sectional tapering, more or less to compensate for any cross sectional dimension changes in the main keel due to introducing any foil shaping. My next step is to strip plank these tapers with 1/2 by 1/2 in. strips to form the male mold base.
     

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  5. viking north
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    viking north VINLAND

    Strip planking over the tapering ply bulkheads using 1/2 x 1/2 in. clear spruce and 18 gage air nailing. Other than being symetrical no great special care has to be made for a super good finish as the strips will be filled and sanded before applying the a skim coat of plaster. This in turn is sanded for a smooth finish before being primed and fine sanded again to form the final one time use mold. This process will continue over the next couple of weeks until the keel male mold is completed. While this is basically a repeat of my former trials previously posted on the thread, I will continue with postings of the work in progress referring back to former photos where necessary.
     

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    Last edited: Dec 19, 2012
  6. hoytedow
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    hoytedow Wood Butcher

    Which keel did you decide upon? :)
     
  7. viking north
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    viking north VINLAND

    Hoyt, reference post #81 the middle choice. I have some concerns re the keel bolts for the skeg as the existing shaft tube prevents me from installing new bolts. However a little luck is on my side in that there are three existing 1/2 in. bolt stubs pertruding about 1 1/2 in. down thru the present keel in that area. I can attach to these by either threading or welding extentions. That plus by bending a pair of new keel bolts aft in combination with a glassed in 1/2in. thick stainless custom shaped flatbar running the entire back end of the existing keel and new skeg should make it all bullet proof. If I have any doubt on strength it is a simple matter to revert to a full keel setup. I tend to over build by 100% in the keel areas so it should split coral heads :D ---Geo.
     
  8. hoytedow
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    hoytedow Wood Butcher

    That one looks the most nimble. :D
     
  9. viking north
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    viking north VINLAND

    Nimble---nice name for a vessel -- Yes Hoyt the cutout allows for better tacking in light winds, plus with a little playing around with foil shaping in the new keel section should give some windward gain. The proof will be in the pudding as they say but most important get it done and enjoy the fruits of my labour as you have done. ---Geo
     
  10. hoytedow
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    hoytedow Wood Butcher

    The difference being like the comparison of a grape to a watermelon. :)
     
  11. viking north
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    viking north VINLAND

  12. viking north
    Joined: Dec 2010
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    viking north VINLAND

    Once I got the strip planking all tidied up I gave the inside surface a thin coat of Bondo hair to stiffen it all up in prep for a quick power sanding of the exterior before applying a surface coat of auto body filler. This in turn will be finish sanded, taped with alum. plumbers tape and waxed ready for glassing. The entire male mold will receive the same treatment. Next post installing the mold's cap over this area.
     

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    Last edited: Jan 3, 2013
  13. viking north
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    viking north VINLAND

    For the cap material I used a piece of scrap 1/4 mahogony ply. I scribed two pencil marks 5 in. on either end of the ply and used these as centering longitudional reference points when I placed the ply on the new tapered keel addition. Then held it all in place for outline marking by making good use of a few pieces of my lead ballst. Once removed and on the bench I ran a line from end to end using the 5 in. marks as references. Using this center line I can make a few measurements and see how symetrical my newely added keel section is. In this case I was about 3/16 out on the right side for about 8 in. of length. I cut the ply cap piece to reflect this , I.E. cut it symetrical on both sides off the center line. When fastened to the new keel piece I simply planed this section of strip planking away to match the symetry of the cap piece. To fasten the cap down i used thickened epoxy again putting weight ballast pieces to good use. I glued rather than fastened using nails allowing me to route the edge creating a little round over without hitting nail heads. Next step is to tidly (NFLD.saying) it all up in readyness for glassing. My next posting will be continuing with the taper section strip planking down along the rest of the keel, cap it all in readyness for the fin and skeg male molds/plugs. These will be build as seperate units on the bench and fastened in place. Sad to say the previous units i built will not suffice for this new professionally designed lengthened keel. However all is not lost as it's now old hat to build them- :)
    l
     

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  14. viking north
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    viking north VINLAND

    Completed the strip planking of new keel's male mold's taper section. In one of the photographs you will see a couple of foil patterns. These were used to design the amount of taper of each of the molds bulkheads which in turn determines the cross sectional width of the taper section at any point along it's length. The idea here is to mate up with the prefabed fin and skeg molds,both of which will have some foil shaping. This continuation of the strip planked tapered section male mold will receive the same treatment as that in the bow section. Some hand planing, sanding, a thin coating of auto body filler, more sanding in ready for priming, foil taping and mold wax.
     

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    Last edited: Jan 11, 2013
  15. viking north
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    viking north VINLAND

    While waiting for the arrival of my specialized fiberglass sanding paper in rolls, i thought it might be a good idea to digress a little why i felt it necessary to install a tapered section onto the origional wide keel and not just directly attach the new professionally designed fin and skeg without it. The problem as i saw it was really in the forefoot area between the lower part of the stem and the leading edge of the to be installed new fin. As previous photos show this part of the origional keel (forefoot) presented a rather wide blunt face interacting with the oncoming water as the vessel encountered the sea. Right or wrong ( I am not an designer) but my gut feeling was three fold. First it just plain looked ugly, and you know the theory on that. Second, is what I call the Dutch Lumber Barge effect -- just plain old resistance punching thru seas and third, enhansing weatherhelm thru lacking "Bite". I.E. A sharper entrance in the forward underwater section creates "Bite" reducing the tendancy of the bow to "Fall Off" when going to windward. All this of course within reason but based on good solid theory."Skene's page 91 does an excellent job of explaining. While it all sounds good there are some other side effects: While adding some plus in the lifesaving ability to "Heave To" it could reduce manouverability a little. All in All most important, it now looks most beautiful :D
     
    Last edited: Jan 15, 2013
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