Centerboard or keel or both

Not much to say since last post, other than a lot of dirty sanding time on the hull, before flipping it. But now, I should be OK in the future. I added fiberglass on the hull sides up to the deck, in and out. I also laid two layers of fiberglass on the hull external bottom, for tear and wear.

Then, flip it...

Now time is for centerboard and keel. This is the design change I am trying, since I would like that this boat be either able to have the shallow draft or the preformance with the keel.

A piece of rope, four pulleys and some magic later.... Center board is gone!

Oooohh, how does that work? OK, here is a picture of the trick. You notice that the centre board is not the final one... The final one is ready, but way to heavy for that dummy run.

To install the keel, which a bit thinner than the centerboard (50 mm vs 60 mm), we install a box that fits inside the centerboard well. Note that the bolts for the centerboard go on each side of the keel.

Finally, in position in the large saw cut in the boat's bottom...

Lady C. is making progress!

Lifting keel and daggerboard

Weather in Houston area is not really enjoyable at this time of the year. It is either warm or cold and it rains. I try to catch all warmer days opportunities to progress with the epoxy. Waiting for the plywood to arrive, I continue on the keel and daggerboard.
The lifting keel has now its final shape before fiber glass layering. It was a bit longer than expected, the wood being really hard. From the initial shape, I mainly use the electric planner to get to the final result, with some final sanding.
The bulb model is made of 1/2" styrofoam plate from Lowes. I cut discs at the size of the drawing and glued them together with cyanocrylate super glue. It is not the best glue for this purpose (tend to eat/melt the foam), but the result is good enough. Each disc that is in the middle of the keel has a cut out for the fin. To cut the styrofoam, I used a soldering gun, it goes very fast. Then all that is shapped to the right dimension. Next step for the bulb is the mold and then I will take this to the foundry for lead pouring. I still need to figure out how to do with the hollow shape of the fin in the bulb, may be use cement or plaster... I will see this later.

I received the steel also for the daggerboard. Instead of welding pieces of flat 1-1/2"x6" and 1"x4" flat bars, I used 1"x10" flat bar with 1/4"x6" flat bar and epoxy glued them on both sides. Like this I avoided any welding. I ordered the flat bar 1"x10", but I had to cut it to shape with my grinder. It took me a while, but it is done...

That the farther I can go, now I need the wood and the fiberglass to continue my boat...

First progress

So this week, I ordered the plywood, the epoxy and the fiberglass. I choose to have the plywood precut, I do not have that much time and this will save a lot of it on this project and ensure a perfect shape for all the sheets.
Also I started with the keel fabrication. I used 18 beautiful knot free pieces of 3/4" x 1-1/2" x 72" (19 x 38 x 1,828 mm) red oak from Lowes. They were all cut to shape and glued together one by one. 14 of them are together now. However, following the last talks on global warming in Copenhaguen, the temperature dropped here in South East Texas and I am waiting for the temperature to go up again to finish this initial part. Hopefully, it will be much faster than waiting for the global warming.

Re-engineering

This lifting keel capability has been taking my mind for too long and I was not able to find a lifting solution that I liked very much. In fact I would like a centerbord version for easy launching and shallow water sailing, with the at sea performance of the keel version... The big issue with the keel version, is that I am afraid it becomes so complicated to launch and get started, that it will kill the rest of the sailing fun.

Then I came accross a post on the bateau forum http://forums.bateau2.com/viewtopic.php?f=3&t=17984&hilit=centerboard+sb18, where a member was thinking about keeping the option of both centerboard or keel version on the same boat. This allows to use the centerboard or the keel. It does not lock from start, which design the boat version will be. It requires a simple modification of the centerboard trunk and the addition of a couple removable inserts in the centerboard trunk, when the lifting keel is used. The width of the keel and the centerboard is about the same and I will use the holes made for the axis of the centerboard manoeuvering sheaves to lock the inserts in position. The inserts will become the foward and aft guides of the lifting keel trunk. Here is a quick sketch of the option I am about to take.

Keel lifting

There is one big issue on this boat, that is how to lift the keel. The original design calls for the use of the main sail halyard and the boom. Obviously, when you do this, one can no longer sail... It is an issue for me, because most of the time, where I sail, you need a shallow draft to launch or come back to shore. I do not need to be able to really sail, but I need to be able to lift the keel enough, so that I can jump in the matter and be able to pull the boat aground or to the slip way and trailer.

So, I put some thought in it and drafted several designs. I could instal a lifting tool on the deck, but it requires some installation and I won't be really able to sail with it in place, because it interfers with the boom. Another design is the one bellow.

In the lower position:

The lifting system is made of 2 sheaves attached to the re-inforced roof. 2 lines are attached to the keel, just above the hull. One winch will pull everything up or let it go down.

Sport Boat 18

So, now I have the drawings of the Sport Boat 18. A few data:
Length: 5.5 m
Wength at Water Line: 5.2 m
Draft (centerboard): 0.18 / 1.4 m
Draft (lifting keel): 0.46 / 1.57 m
Displacement: 663 kg
Ballast (centerboard / keel): 182 / 166 kg
Sail area: 22.4 m2
I really like the design of this litle boat. It looks very nice and must be very fast.
I went through several blogs of boat buiders and I have two fundamental questions that which I have difficulties to decide:
1- Lifting keel or Centerboard
2- Mast step on keel or mast step on deck
I would like to be able to take the boat in shallow water. Though it is not an absolute madatory thing, sailing in protected waters in the Houston area or at our place in Britany requires some ability to sail in shallow waters. The lifting keel system on this sport boat requires the main sail hallyard and the boom. So impossible to lift the kill at sea... It is a disadvantage in my eyes. However, this is a sport boat, if I start to question the fundamentals of a boat that is supposed to go fast, I should rather built a less extrem design, with a centerboard... I have looked a lot at the drawings, and I think I may be able to have some system install to lift the keel "partially" to meet my criteria. This may be adapted at a later stage. The other issue is trailer and launching from the trailer. Here again, I will need to look at how this can be done easily.
The other question regards the mast and it mainly concern the ability to rig up or rig down. I was more in favor of keeping the original design, but rigging up a mast 9 m long will be a difficult operation. I am looking at a carbon fiber mast to see if I can have it lighter than the alluminum mast. I have seen some of the SB18 under construction for a roof stepped mast. I do not really see how the mast can be rigged up with a hinge system on top of the roof. There are at least one interference with the cuddy top and one with the keel in its upper position.

After putting a lot of thoughts in all this, I am glad I come back to the original design of the boat and wont have to denature it.