Strike 15 trimaran build

Well it worked for me just now

Maybe you have your sprocket-grebe disabled, or the turbo-encapsulator turned on, or some other setting is incorrect

To answer other questions. Yes I have played with sailcut. I have also now drawn a smaller mainsail (9.5sqm) option

Richard Woods

 

Richard,

Thanks for the tip about the turbo grebe sprocket. Might have had one too many teeth, or the wrong toothpaste.
Working for me now.

 

I am open to any recommendations for rig and sails for the strike. The hobie 14 main and jib are looking like the best options. Possibly getting a a fat head (X2) racing version main with classic jib from whirlwind sails

 

Sorry I didn't see this post earlier. I made an approximate mainsail today in sailcut. Matched all the dimensions of the mainsail from the strike sailplan. I gave it ~16:1 chord to depth and moved the draft of the sail closer to the luff. I've never made, let alone designed a sail before. I'm calling around to find local large draft printing and see how much printing out all the full size panels would cost. With dacron at $7/yard I would save money no doubt but I don't know if it would be a fast sail. I have also sent out emails to a couple sailmakers and waiting to hear back on costs.

My main concern would be an outrageous increase on the price of a comparable sized sail because of the brand new design they would have to make.

How much of a price range have you seen with custom sails of this size Richard?

 

Designer knows best, but I would probably get a Hobie 16 main and jib.
I haven't tried to compare the righting moment of the Strike 15 and a Hobie 16 but the increased weight on the 15 should make it comparable.

Much more fun I think, and you could roller furl the jib and put a set of reef points on the main.

 

The h14 and strike 15 will weigh the same at ~240 lbs. Would that extra sail area using the h16 be too much power?

 

My simple calculation for the Strike:
Beam of the boat = ~5' on centerline, so righting moment of the boat itself would be 5x 240 = 1200ft-lb.
Righting moment of a single crew = 5'+~2' for the seated position = 7', so 7x150(assumed) = 1050ft-lb.
Total rm for the Strike = 2250ft-lb.

Righting moment of the hobie is 4' (half the beam) x 240# = 960# for the boat. Righting moment of a single crew 9' (a little hiking) x 150 = 1350ft-#.
Total rm for the Hobie 14 = 2310 ft-lb.

So the Hobie is a little better, but the Hobie is well understood to be easy to flip by digging in the lee bow.
I don't know if the Strike will ride up on the leeward hull. If the leeward hull will not support the full weight of the boat then you will have a clear indication when you are overpowering the boat and you can back off or reef.
All that means to me is with the Hobie 16 rig you will have better performance is medium winds, in higher winds you have to reef earlier - normal procedure for a cruiser.

Looks like the sailors choice based on his/her experience and desires.

Richard should have a comment right about now. Given his stated design goals I would expect him to favor the lower sail area.

 

I attach the small rig sailplan. Only the mainsail is smaller (less roach) the spars and headsails are the same as on the big rig. So you could swap mainsails at any time

Later this week I will be emailing all Strike 15 builders with this sail plan and also the results of discussions I have had from a couple of US based sailmakers.

Those comments will also help Strike 15 builders who are not in the US, and who will probably buy their sails locally

I would expect you to hike a Strike from the windward outrigger. I don't think the Hobie 16 mainsail is suitable. I think 1:16 is too flat for a mainsail. Most "2 man" tents are 4ft wide, the same width as the Strike cockpit

I chose the 10.5 sqm size as I felt that was about the maximum that most people can handle when sailing singlehanded. It's the same size as originally used on the Blaze, for example, a dinghy I know well as I was UK champion in 1998. But I'm much older now so may well go for the smaller rig myself - we'll see

http://www.blaze-sailing.co.uk/index.php/yourblazeinfo/2-site-content/2-blazeracingdinghy

http://www.youtube.com/watch?v=gAWd-YZy5U4

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Double checking all the measurements and i'll be filleting and glassing the hull tomorrow. I still cant decide on some key parts to the boat. Should i widen the cockpit and how do i want the outriggers to collapse. I have always liked the way the cross 18 outriggers fold up and on top of the cockpit. it would be stronger and about the same weight. Also the side trampolines can be left in place all the time speeding up set up time. What do people think?

 

You bought plans from a world class designer.

Make it like he designed it.
The whole boat was designed with his folding system in mind. What do you think you will miss if you casually change the design?

What makes you think Cross will be stronger? The last thing you normally want to do is break a bending beam in the middle. Unless those beams are horribly oversized they will tend to wear out at the connecting joints.

 

I haven't looked at the respective plans but Norman Cross was a more experienced trimaran designer by far, though he did start with cats we shouldn't hold it against him....

I'm going to add though that it makes the most sense to build each respective designer's boat as they intended it. If somebody wants a cross folding system the Cross 18 plans are available. Richard's boats tend to be well thought out.

We do live in a sort of Frankenstein era with design though. boats tend to evolve with a mix and match approach to features, some driven by fashion and others by need. If the designer is still with us it is sensible as well as courteous to consult regarding changes.

 

Cavalier,

Tried 3 times to write this and kept erasing it. So you just get the links.
FYI Cross passed on some time ago, Woods is still around though. What did you mean?

Build sequence: http://www.angelfire.com/in/shideler/sail.html
Article with good picture of the hinge: http://smalltrimarans.com/blog/?p=6989
Cross Website: http://mysite.verizon.net/res78939/id3.html

I know there is a study plan on the cross website but couldn't find it again.

My comment about changing the design refer to the structure designed to support Woods's crossarms when opened. There is a lot designed into the boat which would be useless if the Cross beams were utilized. When you change something completely designed for one method it will be easy to miss something. Happens all the time at work.

 

Upchurch I'm well aware of Norman's work and passing as the end of my previous post shows.

I did suggest anybody changing the strike design should consult Richard to avoid dead weight and other issues.

Finally for cruising trimarans no current designer has really stepped up to the plate. Most trimarans these days are sport boats. A Cross 18 is a great performing small folding tri, with current rigs these can keep up with the current crowd and the plans are very affordable.

 

Since you are wanting to be courteous, please explain the above?

 

It is true that Norman Cross had far more trimaran design experience in all size ranges than Richard Woods has currently accumulated. He also designed cats and was well aware of the uses and advantages of each.

Richard is expanding into trimarans on the small end of the scale, hopefully he'll continue into larger sizes as he expands his portfolio.

As far as Cross 18 study plans, Jeff Turner often sends out information with no charge at all, those interested should send him a email.