Trimaran - Especially Searunner - Owners

[silviris]

Originally Posted by Roy M

Great news just arrived. The boatyard just called and said they had reconsidered their bid and have decided to charge me $1680 for the haulout and paint. I gladly accepted, so I'll be hauling May 31st, pulling the centerboard and replacing it with the new one, pulling the 17 foot propshaft for inspection, pulling the rudder off and inspecting all the hardware, cleaning the seacocks, and repairing small dings. Then, it's time to complete the reefer. My refrigeration guru came by yesterday to inspect the box. He gave his blessings and took the cold plate off to solder on the copper stuff and fill it with eutectic solution. Then, it's time to close it up, fire it up and fill it with fizzy local craft industrial solvents for testing. I'll send pics. Then I can pull the stick and get that out of the way. I may be sailing yet.

That's better! I can definitely do that every couple of years.

[Roy M]

silvirus, you're welcome to drop by the boatyard to check out the "underside" of the boat. It will be at the old Knight&Carver yard in National City. It will be close to your new digs.

[silviris]

Roy: Thanks, might do that! Going to be out of town next week, so I'll have to set up something after that.

What do you think about my previous post about extending the top of the aft cabin?

[searunner31]

Roy did you get a quote from Shelter Island boat yard. They seem to have the best prices and give you more bang for.the buck?

[Roy M]

searunner31, the beam on the 40 is 24 feet. That limits me to one of the two Travellifts in San Diego capable of boats as wide as mine. The only other one that will handle it is in Ensenada at Baja Naval.

silvirus, I don't recommend extending the sterncastle all the way to the end. When you see mine I can show you some engineering tricks that may help you with what you have. It's nice to be able to walk around the stern. In my opinion, the deck originally designed outboard of the sterncastle isn't the greatest for strength and stiffness. I can show you easier than try to describe it in print. seadragon saw it and began to get lustful thoughts of remodeling, but his very smart wife convinced him that there were better options.

[silviris]

I'll definitely be dropping by to check out your setup. I'm looking forward to tinkering with the boat (when I finally get it!) for a long time. I'm never satisfied and will probably change things over and over as time goes on. That's half the fun, anyway!

[Cavalier MK2]

Originally Posted by rossad

OK Cavalier MK2
I will agree on one thing...
Try anything on a dinghy or a dink (strange word) first before applying on a huge area like a Trimaran.
and give it a couple of years and then make the decision.
That is prudent enough for me.

I'm glad we agree on something. That's what I did and it sure works great on the big stuff too. But the softer, less glossy look and easy, fume free, safe application isn't for everyone.

[Mark Johnson]

Originally Posted by silviris

Mark: I also didn't realize your boat was home ported (at least in the pic) in South Carolina. I'm originally from Goose Creek (near Charleston), but I've been out here in California since I started military service. Nice to see another Carolina boy on here!

Actually, Blythewood SC was the location of my "boatyard in the woods" where I built all 3 of my cruising boats. (150 miles inland) Of those 21 years spent in a "personal" cruising boat project, going back to 39 years ago, the first 11 of those years were when I was single, and living in a mouse infested 1 room shack that had been the tack room connected to a derelict horse barn. When you are young & broke, but energetic and REALLY want a cruising boat, you do what ya gotta do. I lived on about $3,000 a year!

Right before I got married @ 35 years old:

My current wife and I had met (on my boat) when I was anchored out in Key West, and then we went cruising to the Bahamas. We soon realized that the SC 28 was just too small for two, so we returned to Blythewood SC to build a larger boat. For the number of years it would take the "shack" would no longer do, so we built a small house 1,000' away first.

Most of the last "almost" 18 years since launching Delphys and selling our house, we lived on the boat in several places in FL, (mostly in the Keys), or out of the country, (Bahamas & both sides of the Caribbean).

Since running out of money for international cruising, (6 years ago) we have lived in New Bern NC, saving up for our retirement cruising years if we are that lucky. Daysailing and week long local cruises will have to do for now...

Charleston is a beautiful town, isn't it...


CABIN EXTENSION:
Roy has far more experience on this one than any of us, as he HAS modified his sterncastle in an attractive way, without loosing strength. He didn't go longer, however, he made more headroom. I agree with Roy, that you loose a valuable space back there if you extend the cabin aft. Listen to him!

From an engineering point of view also, there is a problem... I assume that you mean extend the sterncastle top aft AND take out the shelf & deck below it so that you achieve more than just extra shelf space. That shelf at the aft end of the sterncastle, along with the small deck behind it, is what ties the top of that frame AND the sides of the hull together, to keep them from flexing. If you took all of that deck level out, you would need to make a VERY stout carbon fiber arch or the like, under the new cabin top extension, where the old cabin "used" to stop. This would get somewhat heavy & complicated.

While it could probably be done... imo, the pros for doing it are outweighed by the cons. IF you wanted it bad enough to accept that, I would definitely get John Marples to run the engineering, and determine how much "beef" needs to be replaced. It would be money VERY well spent!

Mark

PS... CONGRATULATIONS Roy, on getting a more reasonable quote!

[silviris]

Mark: I was indeed talking about taking out the "shelf" and extending the top of the aft cabin back to the stern so I could use the extra space for a master cabin for me and the wife. I kinda figured before I asked that it wasn't something that would be feasible. Just hoping to gain separation from the kids while sleeping and that area would be really nice to turn into larger bed. Since I'm neither skilled nor rich enough to do what you suggest, I'll just suffer through with it as is.

Thanks!

[Maren]

I'm going to throw this out and see what happens:

I am building a seaclipper 20 and am looking to do the DAGGERboard. I've noticed that the design says is to make it fit length of the slot. If I do that, it will end up being a NACA 00095 and at the top of the slot there will be 1/2" slop for the board to rattle around in (a 2" slot), minus the amount due to fiberglass in the insides of the trunk. I don't think a 00095 is appreciable better or worse that a 0012 for most conditions. A bit weaker, a bit more efficient at speed and a bit worse with stall.

Option 2 is make the lower section a NACA 0012 and laminate on 1/4 ply at the top.

Option 3 is go with a NACA 0012 and bolster the thickness for the top part as in the first option.

Thoughts?

[Roy M]

Maren, what about making prototypes of each, not necessarily as strong as you'd need for the long term, and testing each? As for me, I chose the "fattest" chord I could handle because I think that it handles the range of conditions. I'm guessing my decision is a compromise, but I didn't want to do this several times, as I need to haul to get the axle pin removed and replaced with each centerboard. A daggerboard allows greater options to testing the foil.

[Mark Johnson]

Maren,
Which ever foil section you choose for your 20, will be fine "performance wise". The differences in speed would be un-measurable. It does of coarse need to be strong enough...

I am unfamiliar with plans for the 20, and was unaware that it was a "daggerboard" rather than a centerboard. In that case, you would be better off with a good snugish fit. You don't want it to rattle around.

IF you haven't built the dagerboard case yet, I would build the board and get it really fair. (NO hollow spots)... Then wrap it with a 1/16" thick but firm spacer of some kind, (perhaps packing foam, vinyl flooring, thick poster paper)??? Then wrap THAT with 6 mill poly as a mold release, and use the now slightly larger daggerboard as a mold, to glass up the daggerboard case for it. A 1/4" thick glass build up should be plenty. Then slide the board out, and pull out the poly mold release sheet. (For taping the 6 mill poly sheet ends together, 3-M's 471 blue plastic tape will do the job, and it too is a mold release) The epoxy/glass will not stick to this OR the poly.

Before or after installing the perfectly fitting trunk into the boat, a few small vertical stringers, like 2 on each side, would stiffen it up. Along with fillets & glass top & bottom, as well as bias cut tapes on the for and aft edges, this should be fine. All of the load pretty much, is at the top and bottom. Of coarse, if you ground it, (which you will)... the for edge at the top, and particularly the aft edge at the bottom, need to be bulletproof. It would be far better to blow up the board than it's case.

I am surprised that these details are not in the plans???

Anyway, all of the daggerboards I have seen on my friend's cats, had a trunk/case that was the exact shape of the daggerboard, but with 1/8" of space, all around. More than that, and it will rattle.

I agree with Roy, btw, that fatter is stronger. This photo is of the section used on my 28's rudder/skeg. It was quite stout! Unlike what I did there, however... Making the aft edge almost razor sharp, but with a flat about 1/8" wide, is fastest. You could make the aft edge larger and rounded first, (to wrap glass around the radius), then build it into that sharp edge 3/4" further aft, out of ALL glass. You can't wrap a sharp edge, but if it is added on and made of all glass, you don't need to.

Mark

[Maren]

Thanks for the speedy replies guys. I agree with both of you that fatter is stronger, and would have thought John would have called it out as a 0012. However, after thinking about it a bit I figured I need to trust his design.

I think what that means is a 00095 board which will use up all the width of the 2x material but a touch more which I'll do with fiberglass. That won't affect the aspect but it will make the board thicker. From there I'll do the trailing edge like Mark said and West out in one of their technical pieces. Depending on how the fiberglass lays and how much space I end up with, I may make it a touch thicker which would make it closer to a 0011 or 0012. Either way, I think I'm going to try that trunk idea, Mark.

And if that doesn't work... I may rip it out and just go with the centerboard option.

[Maren]

So, I thought about this a bit more and here is what I've come up with. I like Roy's prototyping idea and Mark's tight fitting daggerboard trunk idea.

I think I'm going to do both.

That means a wider centerboard trunk that will accommodate a NACA 0012 that I can knock out afterward and compare (Thank you, Roy). That should mean an extra 1/4 piece of plywood on the upper portion of the current centerboard. Once I verify that's right I'll make the trunk around the beefed up daggerboard so it doesn't rattle (Thank you, Mark).

And if there is no difference, I'll still have a spare... unless I rip it out and go with a centerboard.

[Cavalier MK2]

If you want to do a rectangular case (even easier and you can use stock ply) to handle a variety of sections, plastic spacers on the daggerboard running vetically take up any play and act as bearings. A bottom plastic/nylon bearing conforming to the foil section will help reduce water flow in the trunk. Install with 5200 and a retaining lip. I recommend space for a crushbox ala Newick by flaring out the bottom aft edge of the trunk. The hard part about using the board for the trunk mold is ever getting your next board close to the form fitted trunk.....and sometimes you need a new board.