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

That sounds like a wise move.

 

Or,
Move wise, that sounds like... a.

 

Thanks Navygate for visiting my build thread and always Move Wise when making a Wise Move

 

Modifying The Skeg Shell

After taking another look at the skeg I have come up with a combination of a keel bolt pair, an internal flat bar structure that along with the glassing should make this assembly bullet proof strength wise. If you recall from previous posts I was running into a problem installing keel bolts along the skeg's entire length due to access being blocked by the prop. shaft tube. Being bronz and a most professional installation I did not want to disturb it. Initially to overcome what I perceived as a weakness I lengthened the skeg some 12 inches over the designers plans to include an extra pair of keel bolts. Not an ideal situation but I had to move forward on the constructing of the skeg's male mold. So l put this problem on the back burner of my mind as I usually do to solve these problems. Sure enough about 3AM one morning I sat straight up and wide awake with the problem solved. The good old brain did it again without my help. It figured out a way to reduce the skeg size incorporating a reinforcing weldament that was as I said above will be literally bullet proof. Skegs are notorious as a weak point and if I wanted the benefits of a foil fin and skeg keel combo it had to be strong otherwise I would revert to a full keel and put up with it's lower windward and maneuverability performance. The photos show moving the skeg shell back some 8 in. In doing so because the original keel on which it sits tapers in width moving toward the rear, moving the skeg shell rearward results in it becoming too wide to match the width of the original keel. To overcome this I took careful measurements and cut out a longitudinal strip equidistant off the skeg shell's center line. A trial fit of the reassembled two halves shows a successful operation. I've included a photo of the cut off section to display the top quality uniform thickness the glass boys did in their layup. It will now be just a simple matter of glassing the two skeg shell halves back together, a little shaping and filling and the skeg shell will be ready for attaching. In my next posting I will layout a drawing of the skegs keel bolt/flat bar weldament assembly.

 

Thank you VN for hosting your thread.
I must get a Move On

And nice work, good effort, God's speed man!

 

It's been a good day. Strongly fastening the skeg has been a monkey on my back for months. A wise man told me the glassing alone would be more than adequate and I have no doubt that would be the case. However the Irish Stubbornness and the German Perfection (bad mix) in my genes strive to make it 200% stronger than required. In my over thinking brain, that little appendage back there in the stern is so vulnerable and subject to damage. ( In fact they do have a bit of a reputation for such) So my grey matter of decisions is determined that this skeg will split boulders along the Labrador coast. . To attain this level of strength I am on a mission to install some arrangement of keel bolt type reinforcing. An important part of that was those 4 cut off bolt stubs sticking out of the original keel. Well today I made an attempt to thread one, expecting the dam thing to simply spin when I applied torque to the die . If so threading was out of the question and I would have to somehow weld on a section of thread. Not something I was looking forward to due to the high heat that would be generated in a piece of steel embedded in my FRP keel. My first problem was the odd ball diameter of the bolt stubs, which I determined must be metric. Something close to 13/16". My tap and die set had a 7/8 and a 3/4 so I ran the 7/8 first followed by the 3/4. It all worked just great as you can see by the photos .

 

You could have just threaded it M20 as it was almost certainly 20mm diameter but - I have long since stopped expecting anyone in the North American region to consider metric measurements. It really is a major blind spot though.

Yes yes I know - you didn't have a M20 die. That reduces to, the only tool I have is a hammer so everything else must be a nail.

Sorry - you're doing a great job on the boat. But!

PDW

 

Ha Ha --Totally agree with you. Sounds crazy but I use Standard for course heavy work and metric for the details. This has slowly introduced me into the metric world which by the way I do now like to use whenever possible. I have gotten metric distances brain stamped but still having problems with visualizing volumes. My mechanics toolbox has as many metric tools as standard but still haven't progressed to bits, tapes and dies. The youngins here only study the metric system in regular school but often revert to the standard system in trade schools. As a carpenter I only use standard, 4ft.x 8ft. sheeting, 2 in. by framing, 3/4in. x lumber and so on. This is so because the United States is our biggest trading partner and they are still quasi locked into the old British system with one exception their standard liquid volume system being close to metric. A U.S. quart is almost an exact liter thus making the U.S. gallon very very close to a Canadian Metric Gallon but less than a Canadian Standard gallon by .7 of a U.S. Standard Quart or likewise .7 of a Canadian Metric Quart

Re the boat work, I thank you, it being so much more labor efficient for me on this build with the overall design and problem solving looked after by having a qualified person to turn to.

 

It is easier to keep it straight if you remember metric length, volume and weight are all related and based on pure water. 1 liter/litre of water fills a volume 10 cm cubed and weighs one kilogram @ 0 degrees Celsius.

1 liter/litre is 1.057 U.S. fluid quarts.

I am sure you already know this.

 

I have to admit Hoyt I didn't know that Metric relationship. Possibly due my stubbornness of feeling forced to learn a whole new system. Took me long enough to learn the Standard one. I do seem to recall somewhere way way back in time when I was a kid, we in the "Country of Newfoundland" ( before Canada joined us in 1949 (we being the older Country) ) also made use of another more ancient British System. I do recall something about my father needing British sized wrenches to work on machinery and autos. from across the pond.
The threading was a bit of a battle but after cutting away part of the metal with the 7/8 die, some tapering with the mini grinder I got the 3/4 die to grab. PDW. guessed correctly, I didn't have metric dies, If I did I possibly would have gone the same route as my shop supply only contained Standard threaded stainless nuts . Well at least our two countries drive on the same (correct) side of the road. (I stuck "correct" in there before PAR (Paul)beat me to it. )

 

" Well at least our two countries drive on the same (correct) side of the road."

That will come in handy for me and probably save a few Canadians to boot.

Of sourse there is the old British saying, "A pint's a pound the world 'round." That is a direct reference to water displacement. Of course it is closer to 1.04 pounds but that is close enough for a layman.

 

Interestingly enough, water is most dense at 4 degree Celsius not zero.
I was sure that this was also when it occupied 1 litre but thought I would check,
it is completely not clearly defined.
Close enough Hoyt.
Cheers

 

Skeg Keelbolt/weldament

A quick and dirty NTS drawing of an on the fly plan for re enforcing the attachment of the new skeg to the existing keel. This of course in addition to glassing. Nothing etched in stone here, just one idea which i'm sort of working toward. Photos as work progresses

 

Yesterday I dug thru my old shop stock and came up with enough stainless to give my idea on reinforcing the skeg a go. I marked out the stainless flat bar to match the outline of the original keels shape less about 1/4 an inch all around. This was necessary because the skeg shell sits on top of the original keel. Using the plywood pattern I also marked the location of those 4 newly threaded bolt stubs. A little plasma work a little grinding and drilling and presto we have a base that can be secured strongly to work from.

 

I decided to refine the base plate a little more by cutting what is known in the aircraft industry as "lightening holes". In this case the prime intention is to allow the resin in the future installed resin impregnated ballast to bond to the surface of the original keel adding a little more strength to the overall structure along with of course the added feature of reducing weight. I also managed to get to the vertical webs (flat bar keel bolts) and their respective top pieces cut. Recall from the drawing these will eventually be drilled and tapped to serve as the receivers (nuts) for the skeg shoe/ lower rudder bearing structure fasteners. The lightening holes in these allow the resin /ballast mixture to flow and interlock between the skeg's internal compartments. It was not necessary that the workmanship here be pretty as a matter of fact all surfaces have been roughed up with the grinder to enhance resin bonding. A little trick of the trade here -- if you use your grinder to create a roughened surface don't apply pressure just let it dance on it's own weight. Next posting the whole shebang welded into one piece. " The skeg weldament assembly"