Newbie needs help with small DIY sail plan, trimaran setup.

[Woxbox]

One of the nice points of trimarans is that if the wind gets you at the wrong angle, the boat does not tip over. So sometimes you'd want one hand for the sheet, and the other for the tiller. But most of the time, you'd be able to pop the sheet into a cam cleat and have a free hand for the camera, the snack, the beer, etc.

[Lee.007]

Thanks for the advice Dave!

Alright, honey do list complete, holidays are over, time to get this baby done and in the water.
So, I am debating whether to buy a rudder or make one. I have one designed up and was going to make it out of cedar strips laid around the naca foil form, and then epoxy and fiberglass laminate it, with a good hardwood frame inside for strength. I have seen several plans where guys just make one out of plywood and sand the foil to shape, but I am not that good at shaping so I figured I would make foil shaped stations cut with a scrollsaw, and lay the strips like a kayak around it. Or should I just buy the hobie one for 37 bucks? See the pics below of my design vs the hobie rudder I can get from amazon. The hobie rudder says it is about 2 x 8 x 12, which works out to about 0.667 square feet of surface area. Mine is exactly 1 square foot of surface area, but only about 1 inch thick at the max chord. Mine also has a higher aspect ratio, which I remember reading somewhere is better than a low aspect ratio for rudders, if you can make it stiff enough and strong enough. I would really like to just buy the hobie and bolt it on, but I don't know if that is enough surface area to turn my trimaran with a 60 square foot sail. I got the formula(rudder area = 1% ~ 2% of sail area) from a forum somewhere, but given my sail surface area I figured I would split the difference between 1%~2% and make it 1 sq foot submerged surface area. Do you guys think I could turn my boat with only a 0.667 sq ft rudder? That's just a tad over 1% of my 60 sq ft sail, and I like to have some safety factor built in. What do you guys think?
Hobie Rudder.jpgRudder3d.jpgRudder Dim.JPGRudder tip.jpg

[Lee.007]

Ok, so I think I am going to do both. For around $40 I can get the hobie rudder here, and get it bolted on and get on the water. If it works, great, if it doesn't then I know I need to build one on my own. Is anybody violently opposed to this idea and want to talk me out of my plan?

[Chris249]

Like everything in sailing, the answer is "it depends".

It depends on how you sail, the sail shape, the conditions, the speed of your reactions, and the speed at which you think things through and react to them. That rudder is much bigger than the one on my 17ft International Canoe, for example, where it's more than big enough. It's smaller than the one on my Laser, which is not really big enough at times.

Sorry to be so obscure, but the point is that in sailing the hardware is a tiny part of the issue, and almost every design option comes with pros and cons. If your reactions are good and you're open to learning and smart (and without pissing in your pocket, it seems as if you are) then a small rudder like that could work OK. You will have to keep boatspeed up through tacks, and be able to ease sheet quickly after coming through the eye of the wind to ensure that the CLE does not move aft and over-load the rudder to stalling point.

The problem with all of these questions can be seen in the strict one-design classes. In the two most popular strict one designs, the top sailors will just be out having fun in conditions where the mid-fleet championship guys are struggling and the typical guys have long ended up getting rescued. And yet, they are all using exactly the same gear. So by what standard does one judge how a design works?

[Lee.007]

Well Chris, I hope I am intelligent enough to not sink on my trimaran's maiden voyage! And I agree. Everything is a gamble until you try it for sure. So I also did a re-design last night making my home-made rudder with a higher aspect ratio. 6" wide and 24" long submerged area, still giving me 1 sq ft of surface area. I am just going to try different things and see which works best for the typical sea conditions I would consider comfortable enough for my tolerance level. I need to do some research on the "rudder stalling" thing. Not sure I understand what everyone is talking about when I have read articles where other people mention it. But I am sure it has something to do with speed like when an airplane wing stalls?

[Jfitzger]

The rudder on the Hobie Islander I sail is small. Steering is really responsive despite the small size. Tacks have to be perfect or the boat stalls out head to wind. It’s not an issue for me because a quick paddle stroke or kick on the Mirage drive will bring you around. I think this has more to do with the low weight and high windage of a kayak trimaran and very little to do with the rudder.

I have heard of people using larger rudders to increase lateral plane so they can point higher with less slide slipping. I haven’t experimented myself so I don’t know if this works or how it affects balance.

[Lee.007]

Hey Guys, I've been real busy at work since we are back full time now. So, I haven't had much time to work on a rudder. I still plan on getting this thing in the water by the end of February. Even if I don't have my mast rigged up, I am still planning to have the rudder done so I can do some float checks and be able to steer while I paddle.

Thanks for the tips Jfitzger. So I guess there's no such thing as too much rudder?? Well, I guess you could have too big a rudder if it ain't shaped right and causes too much drag. I am freaking dying to get this thing on the water. Cabin fever is getting the best of me....

[Lee.007]

Well, I gotta say I am pretty not happy with the Hobie rudder I ordered. No where near as big as the misleading dimensions led me to believe. Needless to say I will be building my own rudder this weekend. As you can tell from the pics, only about 0.5 square feet of submersible blade on this. I didn't show this in my pictured measurements, but it is no where near 2 inches thick. Maybe 1/2 inch thick up at the top where the through hole is to mount it. Seems kind of flimsy to me. But I just might try both like I said before... no sense in wasting it. I could always use it on a different kayak that doesn't sail.
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[Lee.007]

Oh yeah, I bolted my amas, akas, and kayak all together today! But the whole thing was realllly tight compared to when i clamped it up and drilled the holes. I just couldn't figure out what was wrong....20210118_133652[1].jpg

[Lee.007]

Yup, wrong hole... stupid...

[Lee.007]

Hey guys, today I finished the freaking aka spacers. Took me FOREVER to match the irregular curve on my kayak. The aka wasn't so bad to match, cause it is more of a gradual curve than the kayak. The rear spacer was pretty easy too. But that front one was a real pain. I cut up a lot of good plywood before I got it right. Next time I do this I am going to be sure and build a standard kayak from somebody else's plans that already have the bugs worked out. I have the amas set just so the waterline strikes them just a hair back from the bow like CLC said to do. Here are some pics.

Now All I gotta do is make a lee board, a rudder, finish the mast, epoxy everything, and I am getting on the water!!

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[Lee.007]

So this weekend I was able to get the akas stained and epoxied on 3 sides, and then flipped them over and stained the underside tonight. Not sure if I like this dark color. But hey, if it don't work I'll just strip it down with the sander and re-do it. That's the beauty of a wooden boat. If you make a mistake, you can usually fix it before it becomes catastrophic. Depending on how soon you catch it!!

I also started on my rudder. I printed out my foil forms and glued them to some 5mm plywood with some spray adhesive. Then I cut them out with the scroll saw. I did a dry fit and realized I am missing two. No problem, I'll just cut two more out. I used two 1/4" oak dowels to hold them in place down the center of the rudder. I will also drill two holes in my plywood pivot piece at the top of the rudder, and slide the dowels in and glue them. Once I get the leading and trailing edges glued I will start laying 1/8" thick x 3/4" wide cedar strips on this skeleton, and then fiberglass and epoxy over that. Just like building a kayak. I am kind of worried about the weight of the thing. It is about 2 pounds, I am using 1/2" plywood for the top of the rudder, and 5/8" plywood for the part that holds it and connects to the kayak with a hinge. I am going to use stainless eye screws and a stainless bolt and nut to make a hinge. I'll post more pics when I get The rudder finished.

EDIT: You know, I am thinking about making my lee board the same way... Anybody want to talk me out of it?

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[Lee.007]

Today it rained all freaking day, so I had time to just about finish my rudder assembly. All that is left to do is fiberglass the blade and epoxy the tiller/pivot attachment thing. Is there a nautical term for that? I dunno. Anyway, here are some pics of my assembly today:

Cutting out the leading edge, trailing edge, and foot frame:
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Getting the ribs, spars, leading and trailing edge frame ready to glue together:
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Here is the skeleton all glued together
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Rudder blade all stripped up:
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All the cedar strips glued to the ruder blade skeleton, and the tiller/pivot/rudder attachment thing glued and clamped:
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[Lee.007]

Ok, so I have the rudder blade all epoxied and glassed up now, I'll post pictures later. But I have a question for the group:

What is the best construction method to extend the length of a Birds Mouth(BM) Mast? Scroll up or page back in this blog and you can see pictures of my BM mast. It is a few inches over 15 feet, but I need it to be about 20 feet. I have material to extend it already cut and notched. But I am curious of the best method to connect to mast sections to make them strong and rigid. I was first thinking about going to home depot or lowes and getting a wooden closet rod(those things are pretty strong), shove it down the center, slide the two sections together, and epoxy the whole thing up with maybe some fiberglass covering the joint. It would be a butt joint, with a closet rod inserted inside. Biggest draw back I see to this is the weight.

Another option would be to find an aluminum pipe with an inside diameter of about 2 1/2 inches, and just make a nesting sleeve out of it to hold the two sections together like a tent pole. I don't like the idea of a heavy metal object up that high though.

I feel like the joint should be at the top of the mast instead at that bottom. My reasoning is that it seems like there would be less bending moment at the top instead of the bottom, and I expect the joint to flex a lot more than the rest of the mast. I don't want the flexing to be at the bottom.

I am going to search around the forum, but wanted to get some fresh opinions. So what do you guys think?

[Lee.007]

As promised, here are some pics of the rudder. I have the fill coat of epoxy on it. Still needs some sanding and maybe one more coat of epoxy, or varnish.
Oh, and I cut the stern off my kayak to make a rudder mounting plate area. Most gut-wrenching thing I ever did, cutting into something that took me 6 months to build. :

Glassed and first coat of epoxy, don't judge, I had to scrounge for fiberglass:
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Fill coat of epoxy, whole assembly, using a pair of pliers to serve as a pivot pin for the picture:
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and the most gut-wrenching thing I have done to my kayak. I cut the beautiful stern off . Using 3/4 plywood for a mounting plate:
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[Lee.007]

I am finished with the rudder! Now all I need to do is attach a tiller, finish the mast, and make a lee board. I thought I would show ya'll how I made my hinges. Maybe somebody thinks its a neat idea and might want to make theirs the same way.

I used four 1/4" shank x 1/2" eye stainless steel eye bolts from Lowes, and a zinc oxide coated hitch pin (1/2" dia x 4 1/2" long") from tractor supply for the hinge. Not sure how long the zinc oxide will last against salt water, but I figured if its good enough for farm equipment, it will last until I can find a stainless one. The eye bolts are screwed into the plywood stern plate and the rudder housing. I used some epoxy thickened with fumed silica to make sure the eye bolts stick in there forever. If I ever have to take them out I am screwed. I am thinking about running my main sheet back through the hitch pin handle. That will keep it facing forward so it doesn't interfere with the rudder operation, but I wonder if there will be enough force on the sail to bend my hinge assembly. In this pic you can see the extra epoxy and fiberglass I wrapped around the stern plate. I also put thickened epoxy between the kayak and the stern plate. I am still debating whether or not I want to make a self-centering rig with bungees that hold the rudder at center unless I move it. I almost would rather it get held hard to one side so the kayak just circles around me in the off chance that I fall out, instead of sailing away faster than I can swim. What do you guys think?:
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In this pic you can see where the water line (red laser level) hits the rudder. I don't know how I did it, but I nailed it right on the money where I wanted it. When the kayak is fully loaded to max 300lb displacement, it draws 4.25 inches. I don't know if I will ever hit a 4" draft, but that is where the rudder will be if I do.:
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I took this pic after I installed a "keeper strap". Its just some black bungee cord I had left over from making the hatches on my kayak. The idea is that if I hit a rock, it will flex, and then spring back into position instead of breaking. Also, I put the anchor point pad eyes on the center line so once it pivots past horizontal, it holds it in either the down, or fully up position. The second pic show the up position, but I took that pic before I put the keeper on. I need to change my pivot bolt to a rounded off carriage bolt. The hex bolt grabs the bungee and doesn't let it slip past during operation. I still need to install some lines to raise and lower the rudder. I haven't decided exactly how I want to route them to the cockpit yet.:
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[Lee.007]

Well since my rudder blade turned out so well, I decided to go ahead and design myself a leeboard too. I used the same naca foil that I used for my rudder. Tomorrow I will start cutting out parts and gluing them together. This blade should go easier than the rudder. Instead of using two oak dowels to keep everything straight, I am going to use a 1/2" stiffener all the way down the center of the ribs. The rectangle shape will keep everything straight, instead of rotating around on me like a round rod did in the rudder. Yeah, I know, I could just get a piece of plywood and feather the edges, but what fun is that? And this will be way lighter and also gives me 3 square feet of surface area to better balance my 60 square foot sail as opposed to 1.3 square feet from the CLC design.

Oh by the way, I ordered a 12" long aluminum angle from onlinemetals.com. Only cost me 24 bucks including shipping, and got here in 3 days. I hack-sawed some leeboard mounts out of it and drilled the holes according to the CLC sailrig plan dimensions. I made one hole slotted to allow for any mis-alignment when I put the leeboard on the aka. CLC wanted $60+ to send me two. Now I have enough aluminum angle left over to make more for future sail rigs! Check it out:

Leeboard_Solid.jpgLeeboard_Ribs.JPG
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[Lee.007]

Awesome weather here in Georgia today!! I think we got over 60deg F. Anyway, since the weather was nice, I decided to lash up the sail rig and do a float test in the pool. Almost a year ago I did a float test with my very unstable kayak and ended up taking a VERY COLD swim. Today, I stayed high and dry!! I am really stoked at how this is turning out. I also got some work done on my leeboard.
First observations: I noticed the amas have tons of buoyancy. I was able to step on the ama from the edge of the pool and work my way across the akas to board this baby. It just barely went under the surface. Good thing is, the hatches are nice and water tight, so no leaking at all. Still had dry saw dust inside when I pulled it out of the pool. Also, most people say trimarans have monolithic stability, I agree. I was also really impressed with how solid the lashings were. I rocked back and forth port to starboard to see how much heel I would get, and it was super stable, hardly moved at all. And there were no groanings or creakings or movement at all from the akas. The lashings really hold tight.

All I need to do now is finish my leeboard, install the mast and finish it. I see the light at the end of the tunnel!
Below are some pics:

Easy does it now, that water is colder than a well digger's a$$ in Cut Bank, Montana. We don't want any hypothermia... careful... careful...
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Woo Hoo! Nice and dry!! One thing I noticed, the Amas are kissing the water exactly like I planned them to with weight in the kayak. Can't be more happy about how the dimensions worked out.
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Here she is with the First Mate (Daisy) inspecting the ama's for seaworthiness. Sorry bout the lighting, the pool was half shaded.
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And here is the beginning of the leeboard I designed. Hopefully get this thing done before next weekend. Then all I have left is the mast, and its time to weigh anchor, sail to distant shores, hoist the jolly roger, pillage and plunder the villages!
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[Lee.007]

Hey guys, I got the leeboard assembled, stripped, and have one side 'glassed and epoxied. Waiting for it to cure overnight.

I have a question for the forum now - - It is time for me to work on the mast. I am doing this on the super cheap, so I am building the birds mouth mast, and I am going to extend it another 5 feet. My sail is the re-purposed Laser sail, about 60 square feet. I am thinking about making some robands to attached it to the mast. What is the best way for me to attach the halyard to the top? Here are my options I am considering:

1. Nylon pulled totally enclosed in the mast, halyard running through the mast aft to fore.

2. Nickel Electroless plated steel pulley from Lowes / Home Depot mounted to a plate attached to the top of the mast.

3. Same Nickel pulley, only mounted inside the mast, halyard running through the mast, aft to fore.

What's the best way to do this?

Oh, here are some pics of the leeboard I made:

I was planing it down and scraping the glue blobs off when I tore out a freaking hole. I know I said several choice words that would make a harlot blush:
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So I patched it with a scrap piece I found laying in the floor. Its ugly, but I didn't want to spend hours trying to match the color. took me long enough just to get it sanded down flush:
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Here it is glassed and epoxied on one side. I will do the other tomorrow. That freaking patch stands out like a pirate's eye patch. Drives me nuts to look at it, but oh well:
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So let me know what you guys think the best way to rig the halyard to the mast should be. Thanks!!

[Dusty Yevsky]

What's the best way to do this?

Looking great! As far as the halyard goes you should also consider a simple "bee" hole at the top of the mast. I've got four boat with sails ranging from 50 to 90 squares and never, ever had a problem raising or dropping sail using a bee hole. Simple, cheap, failsafe. KISS definitely applies.

[Woxbox]

I agree with the bee hole, just be sure to have it shiny smooth and neatly tapered. Once the sail is up, you'll tension the luff with the downhaul.

[Lee.007]

Thanks for the tip on the bee hole. I did some preliminary google searches, and the search results I got were all about how to get bees nests out of your mast. Soooo, I will have to dig deeper to learn how to make a bee hole.

In the mean time, I have glassed and epoxied that other side of my leeboard. I was wondering if you guys could tell me if you have had any experience with the cheap 3m fiberglass you get from lowes and home depot. I think it is like 6 oz fiberglass, 2ft x 4 ft sheet. I am impatient and didn't want to wait on shipping for more glass, so I used it on my leeboard, and it seems as if I starved the fiberglass instead of fully soaking the weave. See the pic below. But, no matter how much I worked it with the squeegies or my fingers, I could not get this fiberglass to soak up the epoxy like the 4 oz glass from Raka does. Even after the fill coat(in the pic below) you can still see the weave. Did I do something wrong, or is that just they way the cheap stuff at lowes and home depot looks after you glass it? I am using Raka 127 resin and 350 non-blush hardener. On everything else I have done, it becomes crystal clear after you apply it. Oh, I added some pics of the leeboard striped side, and also what it looks like on the kayak. I like the stripes, keeping the theme from the aft section of my amas.

Why is the weave visible?:
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Starboard side of leeboard glassed. I like the stripes!:
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Mounted on the kayak:
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I put these lines on here so I could use them to remember what setting worked best under different conditions for sailing. They are set at 30 deg increments from 90(full board in water) to 0(board out of water):
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[Wiley Baggins]

Thanks for the tip on the bee hole. I did some preliminary google searches, and the search results I got were all about how to get bees nests out of your mast. Soooo, I will have to dig deeper to learn how to make a bee hole.

It's been a while since I've made one, mine was for a lug rig. I just drilled through the mast and then angled the bit up-and-down a few times to make the hole oval in shape. Also a bit of circular motion for a smooth ramp into/out of the hole. My mast was solid for its full length. Apologies for not having read the entire thread. If your mast is hollow you'll need blocking for the section with bee hole. It needs to be a bit oversize so the line doesn't jam, even if it's a bit swollen from being wet. I coated mine with a graphite powder/epoxy finish.

[Dusty Yevsky]

Yep, just like what Mr. Baggins said. Drill a hole large enough so that your halyard can run freely through. The entry and exit need to be rounded. Last mast I did, I drilled a 1/2" hole and then gingerly plunged a round over router bit ( 1/2" bearing) into the hole. I did this on a drill press but I'm sure a handheld router or drill would be fine. Smooth it out with sandpaper and then epoxy it, with some graphite powder if you're worried about friction. I'm not sure if your mast will be fixed or rotating but if fixed make sure you drill the hole athwartships.

[Woxbox]

That's cheap or contaminated fiberglass. It needs to be treated with good sizing to take the epoxy well. But there's probably not a strength issue there, just a cosmetic one.

Another name for bee hole is dumb sheave.

[Lee.007]

Thanks Dave! I was getting frustrated trying to find a bee-hole design and all I could find were DIY's on how to build bee hives for bee keepers. Nice diagram, I like it, I am a visual learner(but aren't we all really?).

As far as the fiber glass goes, unless it was contaminated at the factory, I will have to agree that it is just cheaply made fiberglass. I took it straight out of the package and put it right on the board. I am pretty careful about that cause I don't like un-necessary dust getting in my epoxy finish. I didn't know about the sizing. Is that like regular fabric sizing that I use to press my uniform? Or something special for fiberglass?

Anyway, the leeboard is done, and I agree it shouldn't be a strength issue. By the way, for those that may be wondering, the leeboard weighs in just under 5 pounds. And it is pretty stiff. After I mounted it in the brackets on the forward aka, I pushed on it laterally(athwartships, learning my nautical terms!) to see how much give it had, the only flexion was right at the bracket. The leeboard itself did not bend. I am calling it good enough!

Now its time to finish my mast and get on the freaking water already!!!!

[Lee.007]

Ok, now that I understand the dumb sheave, just wondering if anyone has ever lined it with a copper pipe, say 3/4" diameter, with flared ends in order to keep from fraying the halyard? Just an idea I had to make the halyard slide easier through the sheave, and protect the wood.

Actually, I guess one could also drill the hole oversized, fill it with epoxy, then re-drill and counter-sink / counter-bore the epoxy to create a flared conical entry to keep from fraying the rope on the edges of the hole. Or does it need to be somewhat of a radiused path inside the mast as Dave's drawing indicates?

[Jfitzger]

The 3M Bondo cloth says that it is to be used only with Bondo resin which is polyester. With fiberglass mat the sizing dissolves with the styrene in the polyester resin and it might be the case for that particular cloth too.

[Dusty Yevsky]

Or does it need to be somewhat of a radiused path inside the mast as Dave's drawing indicates?

Yes, it should be radiused. Just counter sinking and boring will leave edges which you don't want. However some 60 grit sandpaper will make quick work of it. Then sand smooth and epoxy.

I lined the rope handle holes in the bow and stern of a 90 lb triple kayak with copper pipe but it was a lot of trouble to get the edges smooth. IMHO, it's not remotely necessary for a bee hole.

[Lee.007]

Thanks so much for the responses guys! I am starting on the mast tonight. I was thinking of making a top plug for the mast out of 3 different sections. The inner section would form the bee-hole. My thinking is that I can create the exact radii that I would need, and sandwich this section between two other solid wood sections, glueing it all together with thickened epoxy. That way I could exactly control the dimensions of the bee-hole. What do you guys think? I may be over-thinking and over-engineering something so simple, but I am using this whole trimaran project as an experimentation / learning experience to educate myself and develop best practices for future builds.

Because I am realizing, you can't build just one....

Also, after making my rudder and leeboard with a strip over forms technique, I am thinking next time I will use my "cedar panel" technique that I used on my amas. So make the panels first, then lay them on the forms. That will allow me to epoxy and fiberglass the inside of the rudder and leeboard panels, lay them on the forms pre-coated in thickened epoxy, clamp them down with rubber bands, bungee chords, or ropes, and then epoxy and fiberglass the outside once the inside is set. I am worried that if any water finds its way inside of my leeboard or rudder, it will rot it out without me knowing until it fails.

I will draw up my mast head 3 sections idea and post later tonight. I have a lot of work to do to extend the mast and build the mast head.

[Lee.007]

So this is what I was thinking of. 4 pieces of solid wood or plywood, 2 in the middle, one on each side to form the outer pieces. Epoxy the whole thing together:

BeeHoleIdea.jpg

[Lee.007]

Ok guys, another question. I have plenty of epoxy. So, instead of making a solid masthead plug out of wood to drill a bee-hole, or making a 3 to 4 piece plug for the bee-hole, is there any reason why I couldn't just pour epoxy down into the birdsmouth mast extension, let it harden up like a kayak end pour, and then drill through it to make the bee-hole? Then I could mix some graphite and epoxy to make a "lubricated bearing" surface for the halyard to slide across in the hole. So would you guys think its a good idea or bad idea to "end pour" my mast top??

[Woxbox]

That's what I would probably do. Or shape a wood plug to an easy fit and slip it in place well gooped up.

[Lee.007]

That's what I would probably do. Or shape a wood plug to an easy fit and slip it in place well gooped up.

So my sail is 60 square feet, and the mast top is 2.5" tapered down to about 2" over a five foot length. My halyard is going to be 3/8". Do you see any issues with strength of the mast top if I just fill it full of epoxy?

[Woxbox]

Not at all. I've had success with much lighter spars.