Loco Perro

[Torchy]

Hi,

Picked up Loco Perro from Tom the other day.

When screwing into a block of epoxy (which might be a bit brittle)...any tips? Jib track has come free IMO because under-engineered. Held by a single screw at centre and this has pulled right through the laminated wooden stringer.

Does anyone have any sections of C Tech sail track or know a UK source? NZ is quite a long way for a bit of plastic  (short section around centre of mast has lost edges in 2 places - might be OK/might not)

Otherwise it's just minor re-roping

A few queries:

* What purchase do people use on cunningham?
* Ditto kicker

..a long shot - has anyone got a C Tech sheave box tucked away anywhere?...old boom kept for spares?

Has anyone got a trapeze harness they want to part with?

[Andrew Whapshott]

If I remember from the day that the track broke, It is held in the middle by a screw, but the ends take most of the stress and I think these were held on with some loops of Carbon tow.    (- Put some pictures up and someone will be advise you on the best way to mend, also I can't remember the details..)

As for the mast track, I sailed her with it and had no problem, but getting the main on/off can be a bit tricky.  It won't be c-tech track but I am sure there is an easier supply somewhere here in the Uk.

Kicker purchase will be a little different as Loco is one of only a few Cherubs to have a Gnav..  Again, when I sailed her I didn't have a problem.   

[Torchy]

Hi Andrew,

Forgot about G Nav. What purchase were you using with the G Nav?...and Cunningham...it's just a mass of ropes and mixed up blocks, so I can't easily tell and it doesn't look like an original set up. There's a massive Barton block and jammer that looks out of place.

I'll measure the track and see if Purple can match the dimensions...low priority following your reassurance but I may as well  get her back to full spec.

Jib track...it looks like the breakage was caused by the centre (single) screw pulling through which caused the ends to fail...or did one end fail and the others go in sequence? It is easy to put 3 screws back where the one failed, which is prudent because the wood laminate needs putting back together and strengthening. Long screws right through from the track will naturally and very easily do this. Previously the screw only held the laminate, with the track bolted to the laminate  (which will remain unchanged).

At the outer ends I am planning to sand back to carbon then re-epoxy with new carbon bands over all...hopefully under the track, if I can get it off. I'll at least match the previous bands and possibly beef it up, especially if you think one of the ends failed first.

[roland_trim]

I have some spare track here. We order it in bulk from Bainbridge. Then you need some Plexus to stick it on with. I've just ordered 5 tubes, but at the price it's now at I'd suggest you buy half a tube (i.e. send ti back to me after using some).

Is the track white or black....

[Torchy]

Ta Slippy...it's white and count me in for half a tube and some track.

Hope to have Loco ready in a couple of weeks and then we can give the folks at Bartley a larf or two...they already think we're nuts after my single handed asymmetric antics in the Tres recently

[Andrew Whapshott]

I seem to remember the track came off at one end; we were two sail reaching,  it pinged off the starboard side and the diagonal load just popped the other two points.  (Sorry this didn't get fixed before.. My crw and I were fairly tired after trollying the boat 1/2 mile down the beach, and Tom had just returned from kenya.. must have forgotten it after putting her away, we had to help recover the SK4 after a fairly swift (20kt) grounding)

I understand that this repair has been done before on loco, so may be worth adding a little more strength this time round..
 (Could be that the plywood is breathing?)  

Wrt to gnav - There is a 6:1 in the boom, which does something.. Nearest guess is that it goes from one end (Tail leading out the boom>cleat), through a cheek block at the gooseneck and onto the gnav. (I only sailed this boat one weekend in Tom's absence, so didn't figure out all her rigging exactly, but she worked well)

The cunningham - From memory these are the two 4:1 pulleys on the deck below the mast.  A piece of yellow dyneema should be kicking about; this goes through the Tack-eye and each end hooks onto one of those pulleys.  This means you can play with the cunningham from either side.  

I was just going to point you towards BS and his magical Plexus..

[Torchy]

Thanks Andy and don't worry about the track damage...I wouldn't be surprised if it had happened before and otherwise it might have happened again on the last beat with us leading at the nationals (dream on). All 3 points of breakage have gone straight through materials (epoxy or wood laminate, not carbon) and there's no sign of prior delamination. It needs a once-for-all fix and I will post photos and get the gurus on it.

Cheers mate

[john_hamilton]

ill give you some helpo if you need it, just give me a call and i can come over

[phil_kirk]

It may be worth bolting the track on. 1 at either end and 2 between them either side of the centre. The chunky I track on the e5's doesn't need much support because it is a large section.  If self tapping into carbon, fibre glass or epoxy i would always drill a pilot hole first so that only the thread of the screw has to cut through the material.

Purchases  either a 4:1 or 8:1.

Normal kicker  needs a 16:1 purchase.
For a Gnav you can use a 2:1 or 3:1 from the bit that slides along the boom or mast and then another 2:1 after that.  I do recall that loco has some part of the system in the boom that you don't want to let go of but never rigged it myself.  i would look at a similarly GNav rigged boat and work out the purchase used on them. 

[Torchy]

Yes Phil, there is a substantial purchase inside the boom. I'll have a close look but I think the 2:1 routed either side will be enough hooked onto this.

Thanks for the info on likely purchase needed.

Would bolting through foam/carbon hold? I'll post photos...it can be done but I'm concerned about crushing the (undamaged) supports...the angle isn't right.

...I'm considering supporting the track with dyneema strops under tension (to the deck behind the track at either end) and using the supports as 'stops' rather than 'anchors'. Might be too Heath Robinson...but it would be bomb proof and light.

..and thanks John HH...might well ask for help with carbon/epoxy stuff. Have you done much of that? I'll need to reinstate what was there even if on its own it is weak.

[Stuberry]

Would bolting through foam/carbon hold? I'll post photos...it can be done but I'm concerned about crushing the (undamaged) supports...the angle isn't right.

I would expect bolting through the composite with a massive "penny" washer on the back to be fine.

However, if you are concerned about crushing you could make an insert of a higher density material where the bolt goes through:
- stick in a piece of plastic tube
- cut a piece of foam out and replace it with HD foam or wood
- make a plug of epoxy

This is probably how I would do it:

1. Sand the area you will laminate in step 7, make sure you take off all the paint, undercoat and filler. It doesn't matter if you go through the laminate as you will replace it later.
2. Measure the diameter of the nut, add 2mm and choose that drill bit. Drill a hole all the way through where the bolt will go.
3. Mix about 10ml of epoxy resin with glass microfibres at about 1 teaspoon at a time until it is the thickness of toothpaste and doesn't run.
4. Pack the hole with resin/fibres mix then tape up the ends with brown parcel tape. This will stop the resin seeping out and epoxy doesnt stick to parcel tape.
5. Wait for your epoxy to set, probably 24hrs.
6. Take off the parcel tape and sand any proud bits. If there are hollows repeat steps 3, 4 and 5 until it is completely flush.
7. Laminate over the top of everything. I would probably use s-glass. It will have about 25% less tensile strength but it will be see-through so you can see where your plug is when re-drilling.
8. Drill the hole again and bolt through.

This means that when you tighten the nut you will be pushing against a very hard lump of epoxy, and you won't crush that.

[Torchy]

The plastic tube idea makes the most sense as if I leave some sticking out the back it will deform as the bolt (with largish washer) is tightened and transfer the load more evenly to the composite (see photos)

It should be a neat, simple and strong solution

Thanks guys

[john_hamilton]

yeh, i built a boat with phil

[Torchy]

Of course!...in the kitchen!

Sorry we didn't get to see you at Boat Show....did you have a kite for me to look at?

[john_hamilton]

yeh, just didnt bump into each other i guess!