Princess 26

[Howard]

Joe:

 

Your description of the forces at play may be entirely correct. The way I was looking at it was a 50# hunk of lead attached to end grain wood, with only a thin margin of epoxy holding them together. I've done enough break tests of things like this to think that would not hold up to the forces in shear and tension.....mostly tension.......the type of strain on the joint when the board is up and the tip is hanging on the end.....as it would be when the boat is being trailered, or when the board is down and dragging sideways across the bottom. Not sure what the shear strength of that thin layer of epoxy is, but figured that, plus two steel bolts, would be greater. But I also don't have a lot of experience with lead tips on the ends of boards. This one was my first, and I don't see where many others have either. So not a lot of info out there to go on.

 

Perhaps what I had not considered in sufficient detail was the contribution of the glass tape. Thinking back to plywood butt joints, it has been said that a simple butt joint, without tape, might not be strong enough to survive a rollover of the two plywood sheets. But add tape to each side and it becomes as strong as the plywood itself. Perhaps glass tape does the same thing here? It would depend on a couple things.......first one comes to mind is the peel strength of the glass on lead, and over time, will the glass be worn or abraded away by sand, gravel, rocks, etc. The lead tip is the tip of the spear and operates in a hostile environment. It is going to get banged up.

 

One aspect of heavily glassing over the joint is how to fair it? Unless you glass the board with the same schedule, you are likely to create a bump at the joint, unless you rabbit out the joint to inset the tape. Also related to this is I am planning to "glass" the board with Xynole polyester cloth for it's greater abrasion resistance. Not sure how that changes the equation vs. something like 17oz biaxial? I would think a single layer of biaxial would not add anything to the stiffness of the CB, so it was only going to provide abrasion resistance. But if it is needed to anchor the lead tip, then I may need to rethink this.

 

Stare at that CB long enough and you start to see all manner of strains on it all over the place. Everything from the tip, to the lifting mechanism, to spreading the load of the lifting mechanism up and down the board. Glass may be doing a lot more than providing lateral stiffness and abrasion resistance.

[Joe Anderson]

You have to be careful when adding reinforcement to a system. If the materials are not matched in their properties and location in the beam, it is like adding dominoes.  No matter how many dominoes you add, if you hit one hard enough they will all fall over. A well designed system is like stacking all the dominoes together and gluing them.

 

That is what we pay Graham the big bucks for.  There were a lot of places on the EC22 that could have worried me but I just figured he knew what he was doing, at least I hoped he did. I have driven Skorpa pretty hard on occasion and the boat has always felt totally unconcerned.

 

I would think Graham has specked something for reinforcement on the centerboard. The simplest surest way is to do what he suggests. It is difficult to think of something that he has not already considered.

 

As far as I know abrasion is primarily a concern on the lower leading edge of the board. That is where I would put the xynole.

 

I wouldn't think you would want to use tape as your primary reinforcement for the lead tip. I think you would want long layers of glass running the entire length of the board. Hard use will abrade the glass along the lower leading edge but that will not effect the strength of the board.

 

The lead tip needs to be rough enough and clean to provide the epoxy/FG plenty of teeth.

 

I embedded a polyester rope in the leading edge and terminated it on the lower side of the lead tip.

[Howard]

Joe:

I see what you are saying with the bolts down the centerline. With a sideways force, essentially, they are the fulcrum of a lever. To counter that, you would want the pins moved out to the edge, but there isn't much room for that. Tape on the outside edge, provided it will stick, is an extension of that. These are to counter the sideways forces. Being on the flat side, there is a lot of surface area to adhere to, so they will immediately spread the load over a wider area.

 

BTW, what the plans suggest is to grind out a shallow groove at the wood/lead joint and lay in 40oz of glass, then glass the entire board over that, so clearly that was the intent. Plans don't give a schedule for how wide the shallow groove is to be (2", 3", 4", 6"?), but 40oz is easy enough to figure as far as the schedule of cloth and related depth to inset it to eliminate the bump.

 

As for sticking to the lead, it will be a pure mechanical bond, so a deep scuffing with 60 grit or coarser will be in order. But that was always the case.

[Howard]

Weather warmed enough to get some work done, so got a chance to finish prepping the CB prior to glassing. As stated, plans suggest "grinding" out material at the join of the lead tip and CB, enough to lay in 40oz of glass. Did a test layup and that finishes out to be nearly 1/8". No worries on the wood part, but what about the lead? "Grinding" to me implies something like an angle head grinder with a flap sanding disk on it, but that would mean creating a lot of airborne lead dust, something I wasn't too exited about being around. So I went looking for alternatives. I tried a lot of options......everything from hand planes to rasps to surform rasps, etc., but best results came from a belt sander, with NEW 36 grit belt. Old belt, previously used on something else just sat on top and did nothing. A new belt started cutting and was aggressive enough to remove the lead as well as the wood. I can hook my belt sander to a shop vac, so that took care of the airborne lead dust.

 

This one is done, but if someone knows a good technique to mill out this type of shoulder on the lead, I'm sure the next guy building one of these would appreciate knowing about it. Molding it in at the pour would be the easy way, but with shoulders, you can't pull the blank out of the casting sand. Or, if you were willing to rip the tip blank in half down the middle, you could form your tip in right and left halves, stack one mold half on the other and make it a horizontal pour vs. the vertical one I did. That would allow you to cast these shoulders in and give you a much better final shape coming out of the casting. Larger, horizontal castings tend to shrink less that a deep vertical one like I did. I also found that not only did the top end shrink, but I also found shallow bowl shaped depressions on the sides, suggesting the tip also shrank in the middle as it cooled.

 

As for the glass, I'm not sure how wide this glass layer is supposed to be, but I have 6" tape so, half that is 3". Hopefully, along with an overlay of glass on the entire board, that will do it.

[Howard]

A bit premature for this, but with a nice enough day to be working outside, I went ahead and ripped out the staves for my rudder blank. It took a good portion of an entire 16' - 2"x12". This one from a reasonably clear and straight piece of flat sawn doug fir, so the grain is all running in the right direction.  Was pleased to see that all of these staves have remained stable, and have not warped or curled up.

 

Will get this ready to go and if we catch a day warm enough for epoxy use, will get this glued up.

 

 

 

 

[Howard]

Yet another item I've started working on is preparation for the keel. Both the keel deadwood, but also what will become the blank for the lead keel that goes on the bottom of it. After a good bit of head scratching, this is what I've come up with.

 

To get the shape right, the keel deadwood and blank for the lead have to be formed in one piece, then split apart. The deadwood goes on the boat.......the blank is used to shape the casting for the lead keel, then it gets tossed.

 

Plans give you the dimensions to make the 3D shape, including the swept back leading edge, which has a double taper.....swept back, but also pinching in towards the bottom. I drew out the overall shape on a plywood jig and will use that to mark all the wood planks used for the deadwood and blank. There will be 6 of them. In the middle, all will have the same basic shape. They only change at the leading edge and slightly on the aft edge. So the template will be used to mark out and cut each of the individual planks to the largest dimension. Only the top edge of the keel deadwood has this exact shape. Only the bottom edge of the bottom plank used to form the keel casting blank has the other shape. The rest are all something in between.

 

I have concluded that the easiest way to assemble all this is to trace out the rough shape on the individual planks using the jig as a template, then rough cut them all out. The template also includes the pattern of the bolt holes, so all of them can be bolted together true prior to final shaping. The top half will be glued together as one unit. The bottom half glued together as one unit. Both bolted together for shaping, then split apart for casting.

 

Lastly, at it's widest point, the keel is 5 1/8", so it can be cut out from 2 x 6 stock, provided the board is very straight. You only have 3/8" left, which means 3/16" on either side. The scrap boards I'm using for the casting blank are not the best, so there will have to be some filling and fairing done to them, but at least they are straight. BTW, figure 12 footers for this.

 

Tool I've started using to drill square holes in stock using a hand held drill is a Big Gator V-Drill Guide.

 

http://www.biggatortools.com/products.html

 

While not as good as using a drill press, for use on larger stock or pieces that can't be horsed to the drill press,  it seems to be working well enough. It will also work to drill a 90 degree square hole through round stock.

[Howard]

Centerboard has been glassed, with some cleanup and fairing to go. But it is far enough along I can now go forward with the king planks on my CB trunk. Board started out at 1 3/4". Glass added 1/16". An additional 1/16" for glass on the CB trunk sides will mean king planks and filler pieces will need to be 2 1/16" to leave 3/16" play/gap for the board to rotate in (as per plans).

 

I was going to use Xynole, and vacuum bag it, but decided to glass it instead, and for a not-so-obvious reason.

 

The lifting eye.......the thing that all weight of the board hangs on is only connected to the two most aft staves, and at this point, one of them is getting awfully thin and actually runs out before it gets to the lead tip. So about all that is holding the lead tip on is the glue line of one stave. Decided it might be best to glass it instead and let the glass on both sides of the board take up and spread the load over the entire board. I feared Xynole might not do that as well. I did put a strip on the leading edge for abrasion (plus and over the rope). Still needs to be cleanup up some and the lifting eye installed.

 

Lead tip has about 3 layers of 12oz biaxial tape connecting it to the board, in addition to the surface coat on the board. That plus the bolts make me think the tip is not coming off.

 

A word of caution. This thing now weighs over 80 pounds and depending on how it is being setup, it will quickly get away from you when standing on edge. If it does, assume it to be a lethal weapon. It needs to be handled with great care and caution.

[Howard]

As weather and work allowed, I have also been working on my rudder assembly. Wanting to get it done so I will be able to get a welder going on the rudder hardware. I want the rudder head finished so I can find the right location for the pintles, so I can know where to mount the gudgeons on the transom. Want the holes drilled, and backfilled prior to glassing the boat. This is almost as bad as "first thing you need to do to bake an apple pie is plant an apple tree". Not quite that bad, but seems like it sometimes.

 

For the rudder blank, I made an error in my estimate of how much epoxy it was going to take to wet the staves and glue things up. Ouch. That took some cleanup. I'm not entirely sure what the best way is to take the lines off the plans and then scale them up to full size, but the way I went about it was to measure the offsets in mm from grids, then draw the grids to scale and mark them off to scale. Resembles the plans so I went with it.

 

Rudder is now cutout and ready to shape. Lacking a CNC cutter (where is one of those when you need it?), looks like I'm going to go the template route again to get both sides shaped as even as possible.

 

BTW, I deviated a bit from the plans for the rudder. Plans call for it to be 1 1/2" thick, which would have meant a NACA foil of about 7.5%. I made it a bit thicker at 1 3/4", which is closer to 9%. I backed off from the 10% chord I normally do, as that would have meant a board that was 2" thick. As it is, the rudder and CB are the same thickness.

[LennieG]

Impressed by your level of detail and precision Howard. I am sure that your end result will be great given your attention to and knowledge of this stuff.

[ricardoramalho]

Dear Wayne, your P26 Twiggy looks very nice.

Did you keep a record of construction hours? I would like to know how many hours of work are expected for the P26, approximately. Does anyone have that information about the P22 also? Cheers! Ricardo

[Howard]

Ricardo:

 

Welcome to the forum. Wayne checks in now and then, so he may have something for you in the future. In the meantime, I think the amount of time it will take you will depend a great deal on your skill level and the detail of finish you expect to accomplish. Experienced builders that participate on this forum are able to finish boats in half the time that beginners do. Maybe less than that. They understand the plans and design concepts better, have skill in solving certain build problems and are efficient in their work.

 

So what may take some of us a year or two, they can accomplish in 6 months or so. It also depends on if you are able to work all day, everyday (and that includes living in a climate that allows you to work year round) vs. only part time as weather, work and other distractions allow. I am in the latter camp. I have not kept track of hours, but what you see in the this thread could have been easily accomplished in only a couple months by a skilled person working steady. Maybe less. With a boat of this size, it also matters if you have help (only needed now and then, but help will be needed), and the extent and size of your shop.

 

But as for a time estimate, even working fairly steady, I would expect this boat to take even a skilled person at least 8 months to a year to complete. I'll consider myself fortunate if I have her completed 18 months from now, but again, I work on it when time and weather permit. Winter, work and other distractions have kept me shut down for nearly 5 months. Only now am I able to get moving again.

 

The Princess 22, while not as large, follows a similar build process, so the time requirement will be similar. The cost of materials will be less, but the amount of time spent on building will probably be about the same.

 

Hope that helps. Again, welcome to the forum.

[ricardoramalho]

Hi Howard!!! Thanks!! I am following your boat too!! I think it is useful to keep a time table while building, to learn about the building productivity. It is also motivating   Some designers provide a "construction time" estimation per project, like 300 hours, 700 hours, 1000 hours. Naturally the construction time will depend on the conditions, like, how many people working, skills of the team, machinery used. Some designs can take quite a long time, but P26 looks quicker to build than any other option. Anyway I hope you manage to dedicate a constant amout of time to your boat, so we can see it as soon as possible floating!! Cheers!!

[W.Robson]

Hi Ricardo, building Twiggy P26 was spread over a little over two years. A lot of that was fulltime, say 40 hour weeks and mostly on my own "with a little help from my friends" occasionally.  Photo taken at Tryphena Harbour, Great Barrier Island on summer cruise.

Good luck with the building

 

 

[ricardoramalho]

Thanks W.Robson for your construction time estimation. Nice photo again. It does take a while to build, as it is not a small boat. Even the P22 looks big, from certain angles. Twiggy P26 had some customizations that took more time to build than perhaps the original project, didn't it? What about the interior? Could you show us a picture please? Cheers!

[W.Robson]

Hi Ricardo, if you search this forum under "Princess 26 interior pictures" you"ll find a few shots , cheers Wayne

[ricardoramalho]

Hi, I found the interior and construction photos of the P26 thanks, very nice job!!!

 

Since W.Robert stretched the cabin, I would like to consult the forum about a similar idea... I thought about keeping the cabin with its original size, but to build a small aft cabin, a bit like the boat bellow (Glen-L25 Duet). I believe the boat could handle the extra weight and there is room for that, perhaps just for an aft head and storage, maybe even a galley. (I could perhaps build the L25, but I prefer the design of the P26, as its construction seems to be a lot simpler).

The aft cabin would take the space of the outboard well, and would use an transon mount for it. What do you think? Cheers!!!! Ricardo

 

[Howard]

Ricardo:

 

I know there is a great temptation to modify the plans to suit one's needs and tastes, but if you go back to the original post in this thread (post #1), you will see my proposed interior layout and it is drawn to scale. You quickly begin to realize that even as "big" as this boat seems, you would be hard pressed to make your proposed changes (head, galley, etc) work in an aft cabin arrangement. I have seen some of those over the years and it would not appeal to me at all. Having seen things to scale as I'm putting it together, the main cabin salon is will be about as "cozy" as I'd want to go for a long distance cruising boat for 1 or 2, as I intend this to be. I can't imagine how splitting up the same area would be to any advantage.

 

Beyond that, while this boat can handle some weight, moving it to the ends (either fore or aft) in a boat of this size (or any size) is never a good idea, plus to get any useable cabin space aft would require it to be sticking up in the air so far it would become windage, not to mention being in the way of the rudder, motor and boarding ladder to get in and out from the water. It would probably also be in the way of the rigging for the mizzen sail.

 

In short, feel free to make your own choices, but I would not do it that way. Just saying.

[Howard]

Forgot to mention, the motor well, as designed, puts the motor in the aft end of the cockpit, at your feet and the controls always within easy reach of the skipper. That is a good thing. Also, as designed, even using a short shaft motor, the prop is set deep and inboard (as is the weight of the motor.......a good thing) vs. hanging off the back of the transom, where even a long shaft motor might ventilate (note I didn't say cavitate for you "cavitation" police) in a chop. Not to mention hang up and hit things.

 

In short, I like the motor where it is. If I had a wish, I'd move it forward a few inches so it would tilt on it's own pivot (simpler to operate and simpler to build), but it is what is and I'm sure it will be OK as drawn.

[Chick Ludwig]

You should ALWAYS consult the designer on any major modifications like this. The arrangement you suggest would drastically change weight and balance for one. I would expect that the Glen-L Duet was designed from the start as a split cabin, center cockpit boat.

[Garry]

I've always thought a split cabin was a remarkable waste of space on anything less than 40 feet. The accommodations on a 26 footer will be small enough without splitting into two even tinier cabins. 26' is definitely not enough for two couples to cruise more than a night or two and they can share the main cabin for that.

 

Just my opinion.