Getting ready to order a new set of sails for my 5.2 and I like the idea of going to the square top sail. This adds about 11 sq. ft. to the main moving the center of effort aft somewhat. Since I'm also planning to change the standing rigging now would be the time to tweek the dimensions so that moving the mast forward to get the center of effort back to where it belongs would be easy to do.

Has anyone sorted this out, or is there enough adjustment in the standard rig dimensions to accommodate this change?

dg

--
dg
NACRA 5.2 #400
This End Up
Original owner since 1975
--

That's interesting. I found that after I got my square top I wanted more rake to balance the boat and keep the bows from burying. I just bought murrays stock rigging and with a shortened forestay to accommodate a roller furler. I also run a second adjuster on my forestay to get the rake I want (about halfway between the beams). I also replaced the stock straight spreaders with ones that could be raked back so I could bend my mast a bit backwards with the downhaul and depower a bit. You can't get as much bend as with a bendy carbon mast but it works.

--
Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
--

Draw yourself a simple triangle, then do the math.
You can only use Pythagoras, A sqrd + B sqrd = C sqrd), with the mast vertical. Law of sines, & co-sines will give you the numbers with mast less than vertical, (ie not a "right" trianlge).
If you measure the chord of your sail, over several spots, you can average what we term in transport category aircraft as the Mean Aerodynamic Chord, (MAC).
I think you will find that the center of effort over the MAC with the new sail is very small. It will take very little mast rake adjustment.
Order the new forestay 1" shorter than factory.
Moving the forestay pin a hole or two should be plenty. I think with 10 hole adjusters, you will have adequate adjustment.
Time on the water is your friend. Take the boat out & sail, then move the mast 1 hole & see if you like it better.
Take some notes, match wind, then rake 1 hole. A GPS & a bingo chart & grease pencil is better than memory.
In the end, simply sailing, in light to big wind will show you where you want the mast rake.

--
Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
--

Quote

I found that after I got my square top I wanted more rake to balance the boat and keep the bows from burying.

Dave, I think the reason you would be burying your bows more now is the addition of 11 square feet of sail in the upper portion of the main. So not only did the center of effort move back, but it is moving up and that is something I hadn't really thought about before.

The reason I would want to move the center of effort back forward (when using a square top) is that if you didn't I would expect an increase in weather helm and if you don't correct that you are essentially slowing the boat down by fighting the weather helm. I have always understood that "fast" is when you have only a very slight amount of weather helm, but I will defer to the racers on this issue.

I also think there is a good reason to bring the pin head sail along for those windy days.

dg

--
dg
NACRA 5.2 #400
This End Up
Original owner since 1975
--

dmgbear55

Getting ready to order a new set of sails for my 5.2 and I like the idea of going to the square top sail. This adds about 11 sq. ft. to the main moving the center of effort aft somewhat. Since I'm also planning to change the standing rigging now would be the time to tweek the dimensions so that moving the mast forward to get the center of effort back to where it belongs would be easy to do.

Has anyone sorted this out, or is there enough adjustment in the standard rig dimensions to accommodate this change?

dg

I have a question regarding this train of thought "moving the center of effort aft" . Where did this information come from? Is this what sail makers are saying about adding a square top sail?

I will explain the reason form my question and then the experts can set me straight. Sail design has been evolving towards higher aspect designs which is a faster sail. What this high aspect means is that the sail is taller, but also narrower front to back. It is said that the aft part of the sail (back half) of the main is a good deal of drag as well as a lot of surface that contributes to pressure to turn the boat over (simply blowing it sideways). The high aspect design result in more forward speed by eliminating a lot of the aft of the main sail sail area as well as adding sail area to the forward part of sail resulting in more force on the boat in the forward direction rather than just pushing it sideways, the go fast equation (the lifting wing part). I would think this would move the center of effort forward rather than back if properly designed. No?

In regard to a square top sail versus the pin head, the assumption I had, was you are taking sail away from the back half of the sail and moving sail area up to the top to get a more uniform wing from top to bottom with the result being a higher aspect shape than what you get from a pin head main. This result is more pressure forward rather than sideway for a faster sail.

The other benefit of the higher aspect sail is that twisting off the square top is very easy thereby reducing sail area very fast in puffy conditions. This makes controlling the sail much easier than conventional pin heads.

In summary my impression of a square top was not just piling on sail at the top of the mast. Am I just making this stuff up?

Thanks in advance



Edited by bruiser on Aug 22, 2016 - 06:11 PM.

I think ideally the daggerboards represent where the center of effort is applied at the water when going to weather. With a jib and main configuration the combined lifting effort of the two sails should work out to be at about the vertical center line of the daggerboards. If the center of effort is in front of the boards the boat will want to fall off the wind and when behind the boards the boat wants to round up. Adding 11 square feet of sail to the main changes this balancing act. In the case of my 5.2 neither the height of the mast or the clew position is changing, but there will be a little more sail working higher up, so the aspect ratio is only changing very slightly.

I asked Andrew at SLO this same question and here is his response:

There are a number of mitigating factors with the square top. As the breeze builds or in puffs, the top of the sail will twist off essentially depowering a little by reducing the effective sail area. This makes the sail appear closer to a pinhead with a similar center of effort. Additionally, the added area of the square top doesn't move the center of effort considerably (there is still plenty of area down low to keep the center from moving too much) though it will be a little further aft than the standard pinhead. In lighter air, you'll likely want to keep the mast a little further forward. We have many customers racing with these square tops and we haven't received any feedback regarding negative weather helm. I don't know if they have adjusted their rigs or if they are just using the sails with their stock setups. You should have enough adjustment with the rig to try the new sail with the stock tune and then adjust from there. I know this is not an exact answer but I hope it leads you in the right directions.

----

So for now I will stay with the current lengths for the standing rigging. If I ever finish this project and go sailing I will report on how the helm works out. When I last sailed the boat several years ago I know I was happy with the balance of the helm when going to weather.

dg

--
dg
NACRA 5.2 #400
This End Up
Original owner since 1975
--

My theory on the square top goes the same with adding a spinnaker to a non-spinnaker boat and that is don't do it unless the boat was set up that way from the start... there may be a problem setting the pre-bend as you spreader bars and set... Again my opinion...

I have not been happy with making the change on both a NACRA 5.8 nor a Prindle 18 which stupid me just did as part of a group purchase where the price was to ridiculous to pass up..

When I did it on the 5.8 years ago there were a lot of adjustment I had to play with, one being the mast pre-bend which got in the ball park on the other the mast rake... there was no issue with the the helm but more so a dragging feel on the boat with a close haul and a beam reach... with the narro beam these boat could point pretty high.... on a beam reach it was OK, but on a broad reach it screamed.. After countless adjustments and recommendation from EP sails I gave up on it... One day I said enough and bought a left over stock pin head sail from the factory set everything back to the known variables and was happy again... the boat preformed perfect on all points of sail... plus there were no DP-N modification factors to deal with..

On the Prindle 18 the jury is still out as I have not had them in heavy wind as of yet but the few times I have had them out there are some pluses and minuses... so far mostly minuses. It does accelerate a little faster and points a hair better, but that is it.. I feel I have lost some energy on the beam and broad reaches. I am planning to have it out this weekend as I'll have a good crew and we're suppose to have some heavy wind.. this will determine if these sails are up for the task or if I wasted money..

I know sounds odd and can open up a whole new discussion..



Edited by JohnES on Aug 22, 2016 - 08:09 PM.

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John Schwartz
Ventura, CA
--

bruiser

the assumption I had, was you are taking sail away from the back half of the sail and moving sail area up to the top to get a more uniform wing from top to bottom with the result being a higher aspect shape than what you get from a pin head main. This result is more pressure forward rather than sideway for a faster sail.

That is how the Squaretop main I have from EP is done, the total size (SqFt) of the main is virtually the same as stock (less than 5% difference) even though it has a pretty large 53 inch top.

Most stock beachcat sails (on the older design boats) have a large roach (curve on the back) of the main so there is plenty of material that can be relocated to the top.

If you entering races using the Portsmouth ratings the penalty for a Non-Standard (within 5% area) main is only .995 but an oversize main is much more (can't locate the ratings on http://www.ussailing.org/ right now)

So if you have one custom made be sure and specify to the sailmaker to keep the sq.ft. close.

--
Damon Linkous
1992 Hobie 18
Memphis, TN

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The reason you cant find the ratings(I emailed them) they voted recently to make the portsmouth ratings only available to US sailing members including the penalty information. The second I get a hard copy I'll post it..

In the meantime you can find the current ratings without being a member by going to regatta network and try registering for an event on the calendar. On most of them, not all, there is a "lookup code" down at the bottom if they are asking for your boats rating. You can find all the ratings there searching by make.

tamumpower1

they voted recently to make the portsmouth ratings only available to US sailing members including the penalty information.

Wow, just wow.

Sailing must be getting too popular, they have to keep it down somehow.

--
Damon Linkous
1992 Hobie 18
Memphis, TN

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DamonLinkous

tamumpower1

they voted recently to make the Portsmouth ratings only available to US sailing members including the penalty information.

Wow, just wow.

Sailing must be getting too popular, they have to keep it down somehow.

All the more reason to move away from the DP-N and go to a system like SCHRS that is dedicated to catamarans...

Also, I have the ratings and modification factors that I downloaded in June 2016 in a spreadsheet if anyone wants them... they haven't changed much over the years...



Edited by JohnES on Aug 23, 2016 - 09:51 AM.

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John Schwartz
Ventura, CA
--

Damon: I sent you an e-mail with regard to the Portsmouth Tables.

--
Jerome Vaughan
Hobie 16
Clinton, Mississippi
--

Ok, so we are all right on this topic. I think there are some risks to making changes to the original designer's sail plan, but there are also some advantages. I have both spoken with and corresponded with Andrew at SLO and here is his response after reading the forum string:

____

If possible, I'd like you to give me a call so I can explain how the area is calculated which will give you a better reference for the area values. Our standard pinhead main is 154 square feet while the square top is 165 square feet. Again, if you call, I can better explain what this means as the two sails are actually measured a little differently.

I read through the forum and "bruiser" brought up an interesting point regarding the aspect ratio of wings or sails. While he is correct, the aspect ratio of a square top mainsail is lower than a pinhead for the same rig. This is because aspect ratio is span (or luff length) squared divided by area. Since the luff length is fixed with the stock N5.2 rig, when you divide span squared by a larger area, you end up with a smaller aspect ratio. He is correct that modern sail plans are higher aspect than traditional rigs but that is because they are building taller rigs with shorter booms and keeping either the same or slightly larger areas.

Additionally, I think "Edchris177" summed it up perfectly in that the movement of the aerodynamic center will be small and that time on the water will be the best determination for how to set the rig up for the square top. Regarding your post about the daggerboards, you mention wanting the center of effort of the sails located at the center of the daggerboards. This is somewhat incorrect in that the rudders contribute to the center of lateral resistance in addition to the daggerboards. This means that the center of lateral resistance is somewhat behind the daggerboards. You don't want the center of effort of the sails directly in line with the center of lateral resistance, but they will likely end up being close. I look forward to hearing from you and let us know if you have any other questions.

___

In my discussion with Andrew he said that the older software package that they used to design their Nacra 5.2 sails for both the square top sail and the pin head didn't take into consideration the overlap of the seams when calculating sail area. With so many more seams and overlaps and overlap width in the paneled sail the old software overstates the sail area, so it is not actually 11 sq. ft. it is something in the 7 to 8 ft. range. To get an accurate measurement they would have to design both sails in their newer software that would better sort this overlap difference out and probably not worth anyone's time.

We also talked about the lateral loads on the rudders a little more and there we got into a discussion of rudder types, angles etc. and that goes beyond this discussion thread.

I really liked corresponding and talking with Andrew who is clearly very knowledgeable, even for an aeronautical engineer. I also appreciate that SLO supports this website, so I am going to order a square top sail and will report my results.

dg

--
dg
NACRA 5.2 #400
This End Up
Original owner since 1975
--

rattlenhum

Damon: I sent you an e-mail with regard to the Portsmouth Tables.

Thanks Jerome

Why the hell would us sailing make it hard to get the ratings(i had the rating page bookmarked) then it disappeared.You think they would be happy to have the info available for all in the interest of making sailing more popular!

--
Carl

Dart 18x2
Nacra 5.8
Acat
Windrider Rave x2 for sale
--

onekiwi

Why the hell would us sailing make it hard to get the ratings(i had the rating page bookmarked) then it disappeared.You think they would be happy to have the info available for all in the interest of making sailing more popular!

It is not like you couldn't ask a US Sailing Member to get it for you either... All the more reason we should adopt the SCHRS handicap for our little Ventura races...

I downloaded the tables to a spreadsheet in June before my membership laps.. shoot me PM if you want it..

--
John Schwartz
Ventura, CA
--

sent you a pm john.

--
Carl

Dart 18x2
Nacra 5.8
Acat
Windrider Rave x2 for sale
--

onekiwi

Why the hell would us sailing make it hard to get the ratings(i had the rating page bookmarked) then it disappeared.You think they would be happy to have the info available for all in the interest of making sailing more popular!

they make it very hard to get info unless you pay for a membership - aka they have their heads up their ass's

dmgbear55

Ok, so we are all right on this topic. I think there are some risks to making changes to the original designer's sail plan, but there are also some advantages. I have both spoken with and corresponded with Andrew at SLO and here is his response after reading the forum string:

....

That was some good info, thanks for taking the time to share. I've always thought sail design is a mix of science, art, voodoo, and BS.

--
Damon Linkous
1992 Hobie 18
Memphis, TN

How To Create Your Signature

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DamonLinkous

dmgbear55

Ok, so we are all right on this topic. I think there are some risks to making changes to the original designer's sail plan, but there are also some advantages. I have both spoken with and corresponded with Andrew at SLO and here is his response after reading the forum string:

....

That was some good info, thanks for taking the time to share. I've always thought sail design is a mix of science, art, voodoo, and BS.

Not for the boys that are spending more on one sail that I had for the down-payment on my house...

--
John Schwartz
Ventura, CA
--

Has anyone figured out what the handicap is for the Slosail square top main is on a Nacra 5.2? It's nominally 11 sq ft larger (7% larger roughly). I would imagine there are quite a few out there. What handicap are you using?

--
***********************
Pairajacks
1985 Nacra 5.2
Corvallis Oregon
************************
--

I was thinking about this setup, how is it working for you?

--
Kenneth Purdy
Hobie 16
Nacra 5.2 (2)
Banshee
First Coast, Florida
--

I just rebuilt my 5.2 and put the new square top on from Slo. It looks great, but I haven't been out yet to play with it.



I'm just a little North of you up here in Scappoose. Get the square top and we can race one design and screw the number crunching.



Edited by dmgbear55 on Apr 04, 2017 - 06:20 PM.

--
dg
NACRA 5.2 #400
This End Up
Original owner since 1975
--

Pairajacks, my club uses a multiplier of 0.995 to my Nacra 5.8 rating to account for my squaretop.

--
Kip
NACRA 5.8na
Chesapeake, VA
--

http://www.whirlwindsails…cra_5.2_SuperR_Main.html

what square top are you getting?
This is what I have, and uhh that's my boat too, the second picture the black boat, but before I owned it, I fly that good yet. lol



Edited by csmonte on Apr 05, 2017 - 10:36 AM.

--
1988 Nacra 5.2
YouTube link to see boat in action:
https://www.youtube.com/playlist?list=PLddinE6IorSrPpZrlvcwAjRzSIQsKYPG1
--

Daviskpjr... are you sailing a SloSail square top? Do you know what your new sail square footing is vs the original? My understanding is that the multiplier is different (than .995) and more severe for sails with larger than standard square footage.

--
***********************
Pairajacks
1985 Nacra 5.2
Corvallis Oregon
************************
--

Yes, I’m sailing a SLO designed square top with the foot of the sail modified to account for a boomlet clew. I do not know the original EP main sail square footage, but estimate my sail plan to be only marginally larger given the reduced area at the foot. You are correct regarding the multiplier; for a larger than standard sail it is 0.98.

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Kip
NACRA 5.8na
Chesapeake, VA
--

Sailed my new SloSail flat top main on Nacra 5.2 for the first time last week in a Thursday night race. I felt it was faster in higher wind (10-15) and about the same in low wind (4-8). I hadn't changed any of the rigging.

Laying out the old EP (presumably original 1985 sail) alongside the new sq top was pretty interesting. The sq top luff is very straight by comparison. As a result, I noticed some wrinkles about a foot aft of the mast when sailing the sq top (downhaul pretty tight). My question - are most people finding that they need to tighten up the diamond wires when changing to a flatter sail?

--
***********************
Pairajacks
1985 Nacra 5.2
Corvallis Oregon
************************
--

pairajacks

My question - are most people finding that they need to tighten up the diamond wires when changing to a flatter sail?

Ask the sail maker how much pre-bend there should be in the mast... Or lay it with the luff and the mast trailing edge and make the adjustment from there. For your 5.2 do you have the adjustable spreaders on the fixed tube that acts a spreader..

--
John Schwartz
Ventura, CA
--

What Andrew at Slo suggested was to increase the downhaul tension. He also indicated that our original downhaul configuration is not up to dealing with these newer flatter designs.

I haven't been out yet, still waiting for my hand to recover from some surgery, but very soon.

--
dg
NACRA 5.2 #400
This End Up
Original owner since 1975
--

On the N5.2, There's a turnbuckle on the diamond wires to adjust tension; that's the adjustment that makes sense to me for a flatter sail. More tension on the diamond wires = less bendy mast. More downhaul makes sense too, but I'm already doing that.

Good luck on the surgery dmgbear55. I like the name of your boat! Very clever. I think I saw that up for sale last year, are you the new owner?

--
***********************
Pairajacks
1985 Nacra 5.2
Corvallis Oregon
************************
--

Yes, in fact I have owned the boat since 1976 then last summer I decided to do a complete rebuild. Now the boat is better than new, until I go out and mess it up.

The diamond wires control flatness by allowing/controlling the bending when the mast is rotated. The downhaul can flatten the main without rotation. So it is possible to get a cleaner airfoil. I forget what Andrew suggested for the downhaul, but likely it was in the 6:1 ratio, much more than was on the original setup.

--
dg
NACRA 5.2 #400
This End Up
Original owner since 1975
--

check the portsmouth tables... off the top of my head you can/may/should take ratings adjustments for:
- non-class legal mainsail (regardless if you're class rating, it's not the sail the boat was designed for)
- non-class legal more than 5% bigger than the original sail

just do the math on original square footage of the main compared to your new sail to see which adjustment is appropriate....

on my H18 I made lots of changes and the ratings adjustments usually confounded the RC:
- non class legal main (but NOT 5% bigger) had a square top
- barely underweight (there's a sliding scale adjustment for got what it was)
- eventually I used an SX jib.. higher aspect than stock H18
- ultimately a spinnaker....

LOVE the Hobie 18 and still sail one when I can, but ultimately I went to a new platform that all these things were designed to be in harmony w/eachother from the start....opened up a whole new world of sailing. (moved to F-16 if you're wondering...)

Bottom line, do what you want and have fun.

Square tops are a tricky addition. I have been using them for about 20 years now, big multis and beach cats. If you don't let them breathe in lighter airs, they can really slow you down. I have found that if the head is too big, it loses it's efficiency. There was an earlier conversation about rake and rig balance. Someone did mention that the boards and hull add a factor, that is correct. A boardless boat will respond differently than a boarded boat. I have raced 5.0s, 5.2s, 5.8s, Tornadoes, Prindles, 6.0s and the sailplan is way different for all of them. If you add a squaretop, you need to make sure the main is cut flatter than a pin head main. The squaretop acts like a lever arm, which depowers the boat easier and keeps it incontrol more. It becomes a compromise between drag vs power & efficiency. Each sailmaker has their magical percentage of what the head length should be. This also depends on the boat. I'm currently using an old Tornado main with the head cut off. it does ok. The top is pretty flat, but it works for the boat. I've done 26.4 knots, so it isn't too bad. My 19, I had a squaretop main (sized as the MX), and a larger jib on a N6.0 foil. The amount of rake looked like a H-16... It was nuts... On the 5.2, I would add a small square top and a larger jib. I used a H-16 boom as a bow foil on my 18-2 mod. Adds good low power. The 5.2 can handle the power. The sail material makes a big difference as well. The plastics are more expensive, but they will hold their shape more consistency. But, do keep in mind that in higher wind, off the wind, the boat will power up very quickly. When you are off the wind, get a puff, and ease the main, the boat does tend to power up more.. just have to be quick on the helm and sheet.


Cheers...
Scott Tuma
Prindle 18-2 Mod
Tornado US626

--
Scott

Prindle Fleet 2
TCDYC

Prindle 18-2 Mod "FrankenKitty"
Tornado Classic "Fast Furniture"
Prindle 19 "Mr. Wiggly"
Nacra 5.8 "De ja vu"
Nacra 5.0
Nacra 5.8
Tornadoes (Reg White)
--

I have been playing around with a variety of modified square top mains on my 1982 G-Cat 5.7. It came with original pin and a cut down Tornado "racing" main. I acquired a 18-2 "fathead" main and cut 18" off the top to fit the mast height and give it a true squaretop cut. The 18-2 is only a little bit bigger (4%) than original in square foot area but much higher aspect ratio with an almost decksweeper effect with stiff downhaul.

So now the original pin is the heavy weather (20+) sail, the Tornado is 12-20mph and the 18-2 is everything below 12mph.

In general, comparing the original pintop with the squaretops: you feel everything faster and harder and can make adjustments quicker. In light air you will get alot more power from the top of the sail than you would otherwise.

Said another way, my pintop feels soft and my squaretops feel hard, and my highest aspect squaretop feels hardest. Yes I know i just listed them in order of old to new but my 30 year old pintop is practically in new condition and is in the best condition of all 3 of my mains.

Hope this helps....

BW

RRoS and DP-N info here:
[url][/https://www.thebeachcats.com/pictures?g2_itemId=126640url]

--
Sheet In!
Bob
_/)_____/)_/)____/)____/)_____/)/)__________/)__
Prindle 18-2 #244 "Wakizashi"
Prindle 16 #3690 "Pegasus" Sold (sigh)
AZ Multihull Fleet 42 member
(Way) Past Commodore of Prindle Fleet 14
Arizona, USA
--

Hi,

I have today just ordered a flathead from Slo for my 5.2, Carl assured me that although it will be a more powerful sail it can be depowered more than the pinhead so is actually better in windy conditions (which we get a lot of here in Western Australia) in summer).

I'd be really interested in what settings you are finding works well for this sail on the 5.2, e.g. what mast rake etc, be great if we could share some experience on using this sail on the 5.2.

Could anyone with a Slo flathead on a 5.2 please post pics of their downhaul setup? My old pintop has blocks fixed to the clew plate, so I need to figure out a new downhaul setup based on an S hook for this sail.

Super excited, now just have to wait 2 months for it to be delivered!

Anthony

I worked with Andrew at Slo and his suggestion was to try the "old" downhaul and then decide what would be needed. Being as I am way behind on my 5.2 project that answer worked for me. But I am really sure that the new sail is going to need way more downhaul tension to take advantage of the material and the shape of this sail. I think the big advantage of these sails is you can keep the mast inline with the leading edge of the main and then pull it even flatter with the increased downhaul. Next question then is the hook on the top of the mast up to the greater load, along with the little swaged bit on the wire halyard and/or the halyard itself?

I owe everyone an update on this finished 5.2 project and my hand has healed enough to go sailing, so stay tuned.

--
dg
NACRA 5.2 #400
This End Up
Original owner since 1975
--

dmgbear55

I worked with Andrew at Slo and his suggestion was to try the "old" downhaul and then decide what would be needed.... Next question then is the hook on the top of the mast up to the greater load, along with the little swaged bit on the wire halyard and/or the halyard itself?

I need to replace my downhaul for the new sail as half the current downhaul blocks are on the tack plate of the old sail, it was 6:1 so I could just replace the blocks on the tack plate with a triple block and an S hook to hang from the new sail, but I was thinking about going to an 8:1 setup like this:



Its kind of hard to see in that image, but basically double block either side at the top, and a cheek block and pivot block either side at the bottom, it has the advantage that you have a downhaul line exiting out to both sides of the tramp.

The swagged halyard fitting was my next concern, I wonder if anyone has ever tried fitting something like the newer hook and loop system on a 5.2, e.g.



Of course the 5.2 has a different head without as much overhang, so might just have to try the swagged wire fitting as is and see if it slips or not.

Dave, have you got any photos or threads covering your 5.2 rebuild (I love the color of the hulls from the profile pic)? I look forward to hearing how you get on with your new sail, be great to get some shared experiences (even if only so I can live vicariously through them whilst I count the months until mine is delivered ). Did you get the laminate radial jib too? I am just going with the new main and the old jib for now. Sorry to hear about your hand, hope you are able to get back out on the water soon!

Anthony

Anthony,
Here is what "This End Up" looked like before getting the name back on the sides:



I did get both sails made by SLO.

In the technical photo albums I tried to document all of the steps I took with the rebuild. Inside that album there are three more key albums that show what I did to the aluminum parts, the fiberglass and the tools I used to get these jobs done.

I also created a bunch of video on this project and I really need to do a summary one and get it up and posted. Here is the first one in the series: https://www.youtube.com/e…o=U&video_id=e8i7dEBBFE4

The whole thing was a kind of design build kind of project, so some of the thinking expressed in these videos changed as I worked through each of the steps. My goal all along was to show how to revive these old boats and hopefully save the next guy doing this kind of work some of my missteps.

I am going to be doing a lot thinking about the downhaul setup. I have a hard time thinking the original halyard system is up the kinds of loads created by a 6:1 or larger system when you really load it up. I even wonder if the old rollers in the masthead can take seriously increased loads, so the overall fix to increase the downhaul system needs to include them as well.

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dg
NACRA 5.2 #400
This End Up
Original owner since 1975
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Hi Dave,

As I think I mentioned on another thread I watched all your videos and am in awe of the work you have done to give your 5.2 a new lease of life, hopefully you have been able to fixup up that cross bar clamp now and get back out on the water?

I just heard from Slo that my sail is ready to ship so should have it here in Australia in a week or two

In the mean time I have been looking at downhaul options and am about to order the parts for an 8:1 (a double block either side of the clew, 3 cheek blocks and two exit blocks at base of mast). I think the halyard will handle 8:1, as I have 6:1 currently (using cheek blocks on clew plate so need new system for new sail), that said I probably have not loaded the 6:1 to its full extent but the previous owner replaced the hook at the top of the mast with a handmade welded up version so maybe the clue is there that the factory hook wasn't up to the load he used on the 6:1, so that maybe an area for you to watch.

Just wondering what ratio downhaul you have tried so far on This End Up, and also did you find you needed more rake by a hole or two, or more spreader rake?

Anthony



Edited by aquaaddict on Aug 11, 2017 - 01:21 PM.

Quote

In the mean time I have been looking at downhaul options and am about to order the parts for an 8:1 (a double block either side of the clew, 3 cheek blocks and two exit blocks at base of mast)

Anthony, I think i have all those parts, all Harken. I can put them on our airplane,(From Vancouver-Sydney).
If you are interested, send me your email via a PM, i'll send you photos.

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Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
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Anthony I haven't changed my downhaul setup yet. The 3:1 was able to pull the sail flat, but not much more than that. I have to believe that your existing 6:1 would be adequate and if you didn't fail the hardware on the top of the mast then so much the better. This new sail is pretty flat in the first place compared to the old dacron sails, so once you are able to induce some mast bend with the downhaul I would think you are there. Overdoing it seems like a way to cause more work and complexity than is necessary. So like Andrew suggested, try your existing setup before changing anything.

I did complete the repair on two of the lugs and got everything painted again. Now I just wish I had dug out the lugs in all of the other positions last year when it would have been easy to do. There is no doubt in my mind that the sharp edges on those lugs contributes mightily to this kind of failure. Just adding more fiberglass like I did a year ago may postpone the failure, but wouldn't completely eliminate them.

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dg
NACRA 5.2 #400
This End Up
Original owner since 1975
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