Trimaran - Especially Searunner - Owners

[Cavalier MK2]

Geez that was only the one cruise total not the year to date.......The paint may be rough but it's tough where it counts, why I put it under the hood instead of in polish and wax. Comforts for some are freezers and microwaves, for others its a good platform that gives peace of mind. The Nicol does spark some bizarr behavior though...lots of monos run their motors with the dink pulled up the exhaust to seem faster sailing. Many boats never unfurl in a day, those that sail seem to put in a couple of hours then hurry off to anchor. We used just a bit over 20 gallons of gas, but we had some no wind days this year and a return schedule.

For the Searunner guys, download the Cross tri size and load chart. Norm counted everything as payload including motors and it doesn't allow the hopeful fuzzy thought of the Searunner Manual. Your designed displacement is the loaded total, weigh the boat and see where you're at. For a 31 designed loaded displacement is 7000 pounds, after that your starting on a trek over the line. Working out your pounds per inch immersion will give you a better idea of what you're fudging.

[Mark Johnson]

Jimske,
As I said previously, it is very hard to judge loading from just a photo, but IF your boat was trimmed level when the photo was taken, then she looks like she was very light, with a long way to go yet!

In hindsight, I realized that my "ama elbows" analogy (keeping them out of the water), was not the best way to express the loading issue. That is why in a future post I only referred to Vaka (= main hull) transom immersion, (= where it meets the bottom plank). The ama "elbows" height above the water, relative to the degree of Vaka immersion, is different between the Searunner sizes, so the Vaka transom's inches of immersion works better.

Not counting daysailing or weekending, short time situations or just living on the hook... But referring to real blue water cruising in "take it as it comes" mode... Imo, the maximum amount that one should load their Searunner to (when trimmed level, mind you), is with NO MORE than 6" of VAKA transom immersion. This may equate to twice the designed payload, I'm not sure.

Less than this, like 4", would be much better, if you can pull it off. This might be 1.5 X the design payload.

The design payload definition? You have the empty hull with it's mast, sails, hardware, winches, engine, cushions & bunks, half a tank of water and half a tank of fuel. Basically a complete daysailor... EVERYTHING ELSE IS PAYLOAD! = CREW, Ground tackle, storm gear, optional sails, tools, spares, dinghy & motor, dive gear, extra fluids, boat hook, books, FOOD, all toys, electronics, etc. You get the picture. For full time liveaboard or serious cruising, this often starts you off over the design payload, but as I said, you can go over, just draw the line somewhere. I mentioned where I draw mine...

For local sailing... I took out 14 people on my SC 28 once, and did fine. I was only trying to express in my posts on loading, that we need to draw a line as to how much is TOO much, IF we want to maintain the remarkable seaworthiness that was designed into these boats.

Hope this helps,
Mark

PS... In a few days, we're headed out to Cape Lookout for 5 days again, YIPPIEE

[Jimske]

Originally Posted by Boatguy30

Jim

I think you said your boat is French made okoume ply. That stuff is about 30% lighter than fir; that makes your boat a lot lighter than most.

That's right - Okume ply. Thanks for that info. I didn't realize that. Good to know.

J

[Jimske]

Originally Posted by Boatguy30

Ok, NO ONE GET PISSED

But it seems to me the guys using the latex paint and other "inferior" methods and products are the ones out sailing!

The other group is chained to the dock or boatyard trying to come up with the time or money to get those last projects "perfect"

I'm still trying to figure out how Mark Hellsall built a SR 37 alone in about 15 months, no Internet I guess!

Doesn't concern me who sails and who doesn't. We all have our own limitations and priorities. Some of those limitations involve time, money and talent. I am sure lots of guys here know ten times more about sailing and Searunners than I ever will. I respect everyone's opinion and am happy to hear.

Regards

[Roy M]

Boatguy, just for the record, it's Mark Hassell, his boat was TALOFAIAOE, and his book was "Love for Sail".

[rossad]

Your advice Mark Johnson is 100% correct and why because you have put your life and soul into your Searunner. And well done. You know Searunners pretty much as well as anybody i believe. Those that are reading this need to understand what you have said about payload and how much we should load these Searunners. 6 inches from the bottom of the central hull is maximum on the transom. This is important and needs to be understood if you are doing blue water. I think you have payload correct for the Searunner.
I notice there are others that have opinion on our Searunners and they dont have Searunners they own other multihulls. They are different. Us Searunner family want the best for our tri's. I do wish John Marples would post and sort it for us all.
And on a better note
Nice to hear some have been sailing. I wish i was but i suppose i am too busy trying to get my Searunner the way i want it.

[Boatguy30]

I was totally thinking of a different mark. Guess you don't know him.

[Roy M]

Then, again, there was Mark MacIntyre, of Los Angeles, who launched SILVERHEELS, a Brown 37 in record time, in 1977. I don't know what happened to that boat, but it was a beauty, and fast. It's interesting how this merry band of Searunner builders shared ideas and resources to help one another make their boats excel. Kind of like what many of the forum participants do today. It's like a very cool club that you get to join if you pay your dues and demonstrate your intentions are noble.

[Cavalier MK2]

I think the wing deck boats are stronger with extra wing frames and the deck and underwing to help spread the loads. The A-frames IMO should be regarded as more fragile. I'll take a look at the pounds per inch immersion for the 31 as it goes over the load waterline. This isn't that hard to do with the plans as you figure out the waterplane "silhouette" area looking down from above (or up from below) like you would a sail Each frame station has the waterline beam on it so each section between frames becomes a trapezoid, measure the WLB for each frame and the length between and work out the area for each section, the bow will be a triangle. The same has to be done for the amas. Now for every inch immersed we can see that the area gets bigger, wider and longer because of the hull shapes. At 6 inches a lot more ama is carrying load and to go from 5-6" down takes much more weight.

How much more weight? We have the area in square feet of our waterplane silhouette, divide by 12 to convert to cubic feet. In salt water 1 cubic foot gives us 64 pounds of buoyancy so times the cubic feet by 64 and you will have the pounds per inch immersion of each hull. Add the 3 totals and you will know how much weight that inch is carrying for the whole boat.

Now looking at our A-frames we need to know what their safety factor is to make a good decision regarding the odds for the current load and weather situation. James Wharram publishes the safety factor he uses and his boats survive a lot too. Maybe Marples could release some beam data.

For bigger loads I'd go wing deck, the wood is more fatigue resistant too by a huge margin, second only to carbon fiber. Plus you get a neat endplate effect for the jibs. Yes the boat might pound more but then in rough going with a big load stress is reduced by slowing down. Of course sticking to the payload takes less homework and fewer chances!

[Roy M]

The 31 is at that curious point where the choice between A-frame and solid deck can be totally dependent on local use versus long range cruising. Mark Johnson (and others, including a 31 I was aboard yesterday in San Diego) have made the decision to strike a balance with "vented" wing decks that can even have removable covers to release water through the deck netting, if necessary. In the 37s and 40s, there is a considerable difference in underwing clearance than the smaller boats, but in heavy chop or head seas, those forward underwings can take a real pounding. That's why the design called for sturdy construction. Mine are doubled 1/4" at the leading edge. Installing it singlehanded was a challenge. I remember the epoxy dripping into my hair as I laid on my back on a scaffold, holding the plywood panels with my hands and feet, screaming profanities to the heavens. It all worked out though because the building gods have a softspot for those who try to do the impossible with minimal resources at the very worst times. And hair grows out eventually, and several cold beers provide sufficient anesthesia to comfort the distressed boatbuilder in need. But underwings MUST be sufficient from the get-go, so no shortcuts here folks!

[Cavalier MK2]

I just added some more math for the homework crowd....Yes a 31 with A-frames makes sense for transport. I like the vented wing option but would have a fairing on the back wall of the vent to avoid the wavetop grab on the flat vertical surface presented there, less windage too.

[Cavalier MK2]

Looked at the 31 vent plans, the designers do call it out as mostly an appearance option. The pounding won't be reduced and the vent is too small for much reduction of air pressure. (but it looks good and saves a little ply) The traditional cruising tris like Searunners and Cross' don't really have a problem there. A better way to reduce pounding would be to have the underwing straight across to the ama, then when you heel it is angled to the waves. Now it presents a flat surface to the waves as soon as you heel that 5-15 degrees that tris operate in. That is a big redesign, though I know from the Nicol, Cross and Tristars it helps. Contemplating it only really makes sense in a new build; vents can be put into existing Searunners.

[md7a]

Originally Posted by Jimske

Oh - note my nets. I have been meaning to tie that one up a little better. Tennis court nets! They are free since most get replaced every year and hold up real well!

Cool idea! So how do your tennis nets attach on the side with no wire and grommets?

Custom nets can run more than $1500 - ouch!

[Jimske]

Originally Posted by md7a

Cool idea! So how do your tennis nets attach on the side with no wire and grommets?

Custom nets can run more than $1500 - ouch!

Originally the nets were simply fishing net. Held up for a long time. Then some guy came along one day and threw the tennis nets on my boat! Yeah - just like that. I don't even know him. Check the local rec department for used ones.

The inboard ama has a 2" stainless screw every 4" where the net just loops over. On the vaka side there are corresponding eye straps. I lace a piece of synthetic luff wire through the eye strap and net. That way I can just unhook the net from the ama and roll it up for the season when it is out of the water.

Near the underside of the beams there is a strip of aluminum which is fastened with the same screws ( every 4") which are on the ama.

The net itself is just about perfect with. You have to remove the stitching and top tape. Also inside the tape is a vinyl covered wire rope. Comes in handy to make some lifelines!

I'll be out again this week and will send you some pics.

Jim

"Do more with less." R. Buckminister Fuller

[Mark Johnson]

My apologies if this is a repeat...

HOMEMADE MULTIHULL NETTING:
The netting that Jim refers to may be the same stuff that I used up front on Delphys, AND for the main nets on my previous boat, (which I seldom actually walked in). Here, I used these recreational nets normally used as tennis nets, as he said, and baseball back drops.

To cover my wing's vent holes of coarse, I used bordered mesh tramps with eyes & bolt rope, which are far better for walking in because they don't stretch much. Thing is, they are about 40% open vs net's 80% open, and mesh tramps are usually professionally made and VERY expensive.

For LARGE spaces on small multihulls that seldom get walked in... Imo, What works best in these applications is 3/16" chord nylon nets, with a woven construction (not 3 strand), and with factory woven joins rather than knots at the connectives between the 2" squares. I have used both, but the above is much better... If you walk in any nylon nets, they WILL stretch a lot!

To make nets with borders that last decades:
Start with black vinyl dipped netting. This stuff is really cheep from wholesale suppliers for recreational nets. Then I'd get enough 3/8" NER "polyester" 3 strand rope to use for the borders.

For a work area I'd used a dock, (with permission), or you can use a sheet of ply, Here, one draws the shape of the net that they want to make, figuring it might stretch a couple of inches. Next, put the net over this drawing, and hook it over a finishing nail driven 1/3rd of the way in, 2 squares beyond the 4 corners. This is followed by doing the same thing all along one edge, then the opposite edge. Next do the ends.
Each time you stretch it over the nail, so that in the end, the netting is pulled DAMNED tight!

Now that you have the net tight with a drawing of your border under that, weave this NER POLYESTER 3 strand rope (West Marine) in and out of each square, until the border rope's ends meet. It must go around the outside of 4 "inner" corner nails at the corners drawn undernieth, then mark it. (These nails will be the nets finished corners). Tighten this border rope about 1" extra, and do an end for end splice, locating it along a side. You will have to create slack to make the splice. You want the "finished" border rope to end up about 1" tighter than the perimeter defined by the net's 4 corner nails, so it is just right, when pulled TIGHT!.

Now pull the 4 border rope corners really tight over the corner nails, and remove the nets from the side nails, keeping the rope's corners in position. This, as I said, is your defined net's shape. Next... Cut away the excess net, (the net squares "beyond" the border rope's in & out squares), and lightly melt the outer joints to prevent raveling.

Next you use non waxed twine to do a TIGHT double wrap and square knot in the middle of each square. (It IS a lot of knots, and takes 2 people). This mechanically bonds the border rope to the netting, so occasional walking or more often than not wave slaps, will not chafe the net back and forth on the border rope.

Now... Do a trial fit, or if feasible, do the above thin twine lashings with the netting actually in position, but held only by its 4 corners. Except for the border rope, which should be TIGHT, the net's center will still be loose with all 4 sides scalloped in. It will tighten up when you attach the nets border sides to the boat and pull them SNUG.

When you are happy with the net, border rope, splice, and lashings, coat the only uncoated (white) parts, (the lashings and border rope) with Sunrise Nets' black vinyl dip. I would use THEIR brand, it stays soft & flexible for decades. Repeat this step 5X more, about 1.5 hours apart.

NOW... you have a factory quality net with a lashed, bonded, and UV coating on it, making it ALL black. The vinyl coating should be refurbished every 5 or 6 years, for an indefinite lifespan! (Ours are 18 years old).

The next step is to TIGHTLY tie into the boat all of the border rope's sides and ends, (corners first), with individual lashings of 1/8" parachute chord, tripled wrapped, & coated separately... You can also use hooks, bolt rope track, or a zig zaged single lashing, from the net's border rope to the boat's eyes, holes, or whatever...

The advantage of individual lashings over the single laced zig zag border lashing like factory cats use, is that unlike the former, in the case of the latter, a single failure can result in the entire netting giving way. (R.I.P. Rob James). Lots of separate lashings will never fail all at once!

There are a lot of ways to make nets that work, but this one really stands the test of time. I guess we spent 4 days on making, coating, and installing ours...

Hope this helps,
Mark