Nacra 5.8 demasted while sailing

I haven't had this happen but can make a pretty good guess as to the cause.

When stepping/unstepping the mast you have to rotate the mast 90 degrees. If you don't the bottom casting on the mast will either break or bend the dolphinstriker back. I would suspect that someone in the past bent the dolphinstriker rod badly and instead of leaving it bent (not the best idea but is will work in the short term) or replacing it, bent it back straight. Bending the rod once is bad because stainless loses a lot of strength when it yeilds (you bend it once) but bending it twice is REALLY BAD because now you have opened any stress cracks that may have formed. If this is what happened it is just a matter of time. Normally those rods are pretty close to bullet proof, a 3/4" stainless bar is rediculously strong.

Next potential cause is a VERY loose rig, if the rigging isn't tight (relatively) or hasn't been tight and the mast flops around it subjects the rod to a lot of extra stress. You may have been sailing with a tight rig but the previous owner could have rigged it loose as a goose. You want it tight enough that everything stays in place but the mast can still rotate.

Lastly the previous owner could have just sailed the crap out of it for 25 years. To cover that possibility I would suggest you also inspect and look at replacing the standing rigging asap because it is likely trash.

The good news is that it's an easy fix, a dolphinstriker kit from Murrays will run you about $70 and is a pretty easy install. The tramp can be patched by your local sail loft or a good upholsterer (you may have to get the material for them from Sailrite).

Regards,
Dave

On my P18, the dolphin striker post passes through the front crossbeam, and srews to the baseplate, leaving about 4" of post above crossbeam, the ball screws onto the top of the dolphin striker post. The post is held in place by the baseplate which is rivited to the crossbar, bottom of the post is attached to the dolphin striker rod. Lot of stress placed on the post and is transferred through the rod to the crossbeam, so yes fatigue would be your probable cause.

Some things to look for as factors contributing to stress would be standing rigging too loose allowing mast to "jump" up and down on ball and sriker rod. Other cats have a "captive" setup where after stepping the mast a pin is inserted through the mast base, it's postioning just below the ball effectively not allowing the mast to "jump off" the ball, always check that this type of setup is rotating freely once mast is stepped.

Turbo
Prindle 18

Got any pics of what's left of the rod?

I will try to post some pics if he hasn't thrown the ds away.

Just out of curiosity. If you tip the boat over, the mast is all that prevents the "platform" from going turtle. If the mast is removed with the boat on its side, doesn't it flip turtle?

The boat did turn turtle and was sitting on top of the mast wich was laying on top of the water with all of the rigging still attatched. It took a great deal of work to get the mast freed from the boat so we could turn it back over again. This was the only way I could think of getting the mast down safely while on the water with a minimal amount of damage. I would love to know of another way to get the mast down safely while on the water with a broken ds.

Had to respond to Turbo's comment about the "captive" mast/ball system. The only time the pin is used is to step the mast. Pin is inserted, while mast is rotated 90 degrees and raised into position. Once the mast is stepped the pin MUST be removed! Can't stress this strongly enough! The reason? If that pin is left in and the mast comes down for any reason without being rotated, you will absolutely destroy that dolphin striker rod, and possibly break the mast base. Plus, it will be bound so tightly that you may have to hacksaw the rod off below the ball to get it loose. Prindles and NACRAS that use this system like a tight rig and that prevents demasting. DO NOT use that pin for that purpose!

Edited by nacraman57 on Apr 25, 2011 - 05:23 PM.

It took a great deal of work to get the mast freed from the boat so we could turn it back over again.

So, if I have this right...you undid all the rigging & removed the mast. Now you are left with an upsidedown Cat. How the Hell do you turn that big of boat back over, without the benifit of the mast as a lever?
Reason I ask is
(A) I'd llike to know, in case it ever happens to my 5.7
(B) I read a post here about flipping the cat on its side, to step or unstep the mast. I have had my 5.7 on its side on the lawn, & can pull it over or right it solo, using the mast as a lever. I couldn't figure out how getting it on its side without the mast, or removing the mast, then getting the hulls eased down would be easier than stepping a mast with the Cat sitting upright.
It seems to me once you pulled the stick, those hulls would want to come crashing down. It also seems like a huge job to get the platform up on its side, to where you could attach mast & rigging.

Nacraman is right about the pin being removed after you get the mast up. I lowered my mast once, with the pin still in. I didn't break anything, but the pin was jammed so tight I had to cut it.

Edited by Edchris177 on Apr 26, 2011 - 04:17 PM.

I had the unfortunate occasion to intentionally drop the mast while my 5.8 was turtled. I believe that the masthead was leaking severely and we could not right the boat with the assistance of a powerboat.

The process of fixing such a mess goes like this:
(1) Pull the boat back to shallow-ish water and detach the rig. Don't lose it.
(2) Secure all appendages (rudders and boards).
(3) Pull the boat to very shallow water.
(4) Find several (quite a few) people to help. Assign some people to each side of the boat, most of the people will lift while the others keep the boat from wandering. Once you get the boat over, guide it down. This is extra fun if your boat weighs > 400 pounds.
(5) Take your lumps. You probably deserve it!

I'm sure Yurdle is laughing at me, even now.

Was not talking about the mast step link pin, read carefully, mentioned the "captive system" where after the mast is stepped a pin is inserted just below the ball almost touching the DS, this allows the mast to rotate freely but will not allow the mast to disconnect from the ball.

To illustrate, make a fist on your right hand, thumb facing you, now take your left hand and cup the wrist just below the fist, now drop your thumb across the wrist, you have effectively demonstrated the captive system.

Edited by turbohobo on Apr 27, 2011 - 06:40 AM.

EdChris it was a real booger to turn over. It took three large men and my buddies wife to turn it over without the mast. I hung on to the righting pole and my friends wife grabbed the daggerboard while two other men lifted the opposite hull out of the water. It was not possible until the third man came along and even then everyone seemed to be in a great deal of strain. It did work though. The pin was not inserted while sailing. I have to give it to you nacra guys, i was very impressed with how easily that boat tacked and pointed compared to my hobie 16. That is until our pleasent saturday afternoon sail was ruined. I am looking at this as a learning experience. I have since learned that the ds was bent when the po bought the boat. He straightened it out and sailed it very hard this way for many years. My thoughts are that we were just unluckly and the ds was just extremley fatigued and this was just the day it gave out.

Ds was bent below the crossbar and broke above the crossbar. A bent ds is not likely the cause here.

Thanks for the info, I thought it would be a real bitch, with plenty of opportunity for damage to boat and/or people.

Turbo...I'm thinking the same as some others. On the Nacra the "captive base" is only captive while stepping or unstepping the mast. The manual says to put the pin in before raising, then,
"Remove the mast step pin to allow the mast to rotate freely while sailing"
The only thing that keeps the stick in place is rig tension.
I believe G Camicks album has a good photo of a non captive base.

Here is the captive base of my 5.7 after stepping, with pin (bolt actually, the pin is somewhere in the lawn) in place. You can see that if the mast falls anywhere except exactly sideways, the mast base will hang up on the DS rod & bend it, along with other damage. Only by turning the mast so the base slot lines up with the DS rod can the stick be safely lowered.
There is no danger to leaving the pin in place...as long as your mast NEVER comes down 😉

Ed, Thanks for the picture! I was trying to dig one up myself to illustrate my respnse to Turbo. I didn't mean to say his post was wrong and if it came off that way I sincerely apologize. I have seen Prindles with the above setup and I think some were retro'ed. I can't explain the back hole on your mast base, my bases have just the single hole in front. Didn't you and I talk about that some time ago? As an example of what can happen...one day at the beach a couple fellows were loading their cat on the trailer. To lower the mast, the guy in front pulled the pin on the forestay, and as the guy on the tramp stepped back to the rear crossbeam the boat overcentered on the back rollers. They had forgotten to strap down the hulls. Anyway, as the front started to rise, the guy on the back toppled off the boat, hulls came down, the mast came crashing down and bent the heck out of the DS rod. The mast got dented on the traveler track, mast base was cracked and it was bound so tightly that despite the twisting, turning and raising the mast it took a hacksaw to free it. A mast coming down out on the water probably wouldn't be as violent but would still suck. The pin I use is a 1/4 x 2 1/4 with a ring-ding on one end and here's another spot to pay attention. Several times I have lowered the mast only to find the ring-ding between the mast base and tramp. DUH! So, back up goes the mast along with much cursing, to rotate it so the pin can be pulled. Another free tip! It's better to unstep the mast BEFORE the Bud Light!

Yeah, it doesn't matter which way you rotate the mast, just make sure you do it so the ring ding is on top once the mast comes down. My neighbors kid gave me a hand dropping the stick last fall, then left. A bit later I noticed the head of the bolt was on the bottom, duh. I just walked back to the garage for the bolt cutters.
A couple of other questions for you. When you sent me those photos of your beam dimensions last year (very helpul, I picked up a proper size V brace outside L.A.) I noticed another beam lying on the floor. Do you a spare you want to sell that will fit a 5.7?
Also, if you ever fliup your cat over again, take some detailed pics of how you have your righting system set up. My bag works OK, but is slower than a pole I think. I would like to build a pole system, to make solo righting easier. I like the system you have 2 photos of, but would appreciate all the details, no use trying to reinvent something.
Jim Casto has an album "the best righting system ever made", but the photos are not a large enough file to blow up clearly, & I haven't had any luck emailing him.

Edited by Edchris177 on May 04, 2011 - 04:39 PM.

No worries mates, no offense taken, I learned something about " captive mast systems".

:prost:

Hey Ed, The righting system on my 5.7 is the "Hawaiian" type righting system I use in conjunction with a bag. Works ok, but I still feel that the best, simplest system is a length of rope tied to the mast base and thrown over the hulls. The pole system I have is on my 5.0. It is a direct copy of Rick White's design. The only difference is that instead of stopper knots, I use a rope lock to quickly adjust pole angles if needed. The 5.0 is my solo boat and I learned early on if your trapped out on a screaming reach miles from home you damn well better be able to self rescue if things go south. The 5.0 has a homemade bob at the mast end, the aforementioned pole righting system and a block at the end of the pole to feed a rope attatched to a righting bag if need be. I'm going to take the 5.0 to the lake this weekend for the first sail of the season and will take some pics of the pole setup and post or e-mail to you. As for the extra beams you mentioned, they came from a 5.0 my brother-in-law had years ago that we just sailed to death. Sails blown out, soft spots in the hulls from stem to stern. We killed it. Saved the beams, mast, rudders etc. Was toying with the the idea of building a plywood-hulled Formula 16 cat using these spare parts. Can you imagine a 16' cat weighing in at or less than 300lbs.? Say, by the way, you're an aeronautical guy... what do you make of the pics of the tail rotor of the chopper that went down on the bin Laden raid. Obviously an H-60 , but, look a little "stealthy" to you???

I use the "knotted line around the mast" system now. Very quick, if I have a crew, takes more time to rig the bag (& generally I need it if solo). I was thinking that the pole would be quicker, do you still need a bag with the pole on you 5.0?
I can sail without dumping, but it's way more fun to go flat out on the edge in 20 kts wind. Solo on the 5.7 is a handful in those conditions. I'm hoping a pole would reduce righting time/effort. I liked the look & simplicity of the system you are using.
I don't know much about stealth, my ride weighs over 800,000lbs & we try to show up on the screens! Other than reducing sharp angles to prevent reflections & radar absorbing coatings I have little knowledge. I only flew fling wing a few times, we were always told they don't actually fly, but vibrate & make obnoxious noise til the earth rejects them!
Major issues with rotary wing are that max speed is relatively slow due to retreating blade stall, & noise. I think the ducted fan tail rotor was developed to to reduce the noise footprint over urban areas. Those long blades, with tip speeds near Mach 1 also make lots of noise. When I was in flight school Kelly Johnson was head of the Lockheed Skunkworks. Many are familiar with the U2 & the SR-71, but they also had myriads of lesser or unknown projects, & I'm sure not much has changed. A stealthy, fast & quiet rotary wing would be the Holy Grail of fling wing.

Ed, funny you should mention Kelly Johnson as I had an uncle that worked in the infamous skunkworks for Lockheed. He would come out to the farm for vacation and it would take several days for him to decompress. He once told me that even though the SR-71 still holds altitude and speed records it was one of the last projects to be designed using a slide rule! Makes you wonder what's in the hopper now. Ironically, the titanium that went into that plane was imported from the Soviet Union! I had the oppourtunity to examine an SR-71 up close at Offutt AFB before it was moved to the Srategic Air and Space Museum in Ashland, NE. I remember running my hand along the underbelly and thinking that it felt like a bunch of pop cans riveted together. Anyway to avoid being accused of hijacking this thread I thought I'd better show you the righting pole you asked about that I made several years ago for my 5.0. It is an Alcoa seamless 6061 aluminum tube 2.25 OD, .083 wall. The hinge is made of the same indestructable acrylic plastic cutting boards are made of. The line is a .25" Marlow pre-stretched although I think some of the new space age Dyneemas might work better. At the end of the pole I installed a small block that I can feed a rope attached to a righting bag if need be. There are more pictures I put in an album in the Tech section.I used rope locks instead stopper knots to adjust pole angles. The angle that works best for me is straight and parallel to the mast. When the boat pops back up the pole swings straight back under the tramp Hope this pic shows up...if not go to the Tech gallery

Thanks, how did you make that hinge unit? It looks to neat to be garage built! Can you right the 5.7 using just the pole? I'd like to eliminate the bag if possible.
One other question, I'm rebuilding a front beam, using the measurements you sent me, & have to drill holes for the V-brace.
Your front V-brace was attached so as to give it a 73" length. I notice your rear beam tabs are at 73 3/4".
Is this 3/4" difference due to hull curvature, (rear hulls at tab must be narrower than tab position on front hulls?), or do you think factory guy was strung out & made a mistake? Do those measurements result in your hulls not being parallel? Or, are the hulls deliberately not parallel, because under load they get forced closer to parallel?
Does your 5.0 show the same difference between front & rear?
I'd like to drill & build the beam this weekend, & can't find any specs. Those photos you sent me last season when your boat was upside down have proved very useful. I have the only 5.7 around, so I can't find another to look at.

Edited by Edchris177 on May 13, 2011 - 10:06 AM.

Guys check out the book Skunkworks by Ben Rich. I'm a bit of an aviation buff (a week in a Jet Ranger 3 got me hooked) and an engineer by education and employment. That is an amazing read and talks all about the F104, U-2, SR71, F117. EC what are you doing to your front beam? I have a spare set of beam straps if you need them.

D.

Righting question...
Can a 170 lb man right a 5.2 with a knotted line mechanism (i.e. line attached to mast base over hull)?

It will be close, I do it easly but I'm close to 220 lbs.

Regards,
Dave

gcamick wrote: Righting question...
Can a 170 lb man right a 5.2 with a knotted line mechanism (i.e. line attached to mast base over hull)?

in the ocean with constant strong winds and a waves to lift the mast from the water you MAY be able to

but on our flat water mountain lake, strong gusts can get my 5.2 on it's side and my 170lbs is unable to un-stick the mast and sail from the flat water at exactly the same time another strong gust is needed to get under the sail and start the righting...

Gray, If conditions are right, I can just get my 5.7 up solo, at 170 lbs. You need to be in good enough shape to hold yourself horizontal,fully extended, on your tiptoes, 4" off the water, then hold that position for 10-20 seconds. The sail will slowly come out of the water, & the mast about 3" off the water. Then I need a bit of wind under the sail, otherwise I sit in that position til I tire out. I bring a bag with me. I bought a large one, but only need a couple gallons in it, & the boat comes right up.
I use a 3/4" line, easy to hold, with some well placed knots for hand grips. Put the boat on its side to see where you need the knots.

Edited by Edchris177 on May 13, 2011 - 06:32 PM.

I am just about to possibly buy a nacra 5.8 for $3000, it's an older one, serial number gone but surely 80s. It's got a couple knicks but also has unique mods that could not be comparted to others. Here is the craigslist.

http://miami.craigslist.org/mdc/boa/3720911556.html

The retrofit wing seats are great, well built and installed, great how they fold in without taking them off. Also has homemade motormount that's better than the one I bought for a Hobie. Has running lights as well as mounts, also coolers built into the hulls surrounded by closed cell foam used to make the hulls unsinkable is just cool. Back cooler used for battery storage great becuase having it flopping around on the deck isn't cool.

But I've noticed that 5.8's seem to draw a little less money demand than others. Do you think it's worth it? Paint makes it look new but you can see from the one picture adding the filling sucked the sides of the hulls in in a couple places, tho it will not break because trust me doing that also made it very solid. The hulls are only about half filled, btw, not front to back. Standing rigging is brand new. Sails old but well cared for.

Also ik this topic is old but I decided to use it because it talks about righting, are these worse to right than the 5.7?

BTW anyone in the south florida/keys area I'm selling my 2000 H17 sport. Will be a CL listing soon. It's a great boat just not what I want, I just got it recently, will probably regret not giving it a more of a chance.

Edited by biscaynecatsailor on Apr 11, 2013 - 10:23 AM.

$3k for a real nice one is in the ballpark.

Biscaynecatsailor,

I personally would not touch it. The owner doesn't know anything about this boat so don't trust anything he says. Here's some info that might help. First, from the ad you don't know if this is a 5.8 (19') or a early 6.0 (20') (which had the single diamonds on the mast). Next, it matters if it was built '85 or newer, which is foam core/sandwich construction. The expandable foam concerns me for oh so many reasons. The mast has a spin tang on it but the hulls (he calls keels) are not set up for a spin. There is little value in the sails, which add no value to the boat. The mast shows a lot of galvanic corrosion where hardware is mounted. Ports have been added forward of the main beam ( a huge no-no on this platform). The aluminum dolphin striker V-bar has been drilled and modified ( another major F.U.B.A.R.). The main beam has been drilled (at a know point of failure) for the retractable benches (wings), which concerns me. And that is just what I can make out from a bunch of grainy pictures.

$3000 will buy you a very nice boat. If you are looking for a late night party barge on the inter-coastal with running lights then this is your horse. Nowhere near a $3000 boat.

After taking a look at that listing, Do not touch it as Phillip suggested. My previous post was just about what a nice 5.8 is worth. This boat is far from that.