Tensioning forestay (plastimo roller furling)

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nathanlee

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Hi All,

I have a Plastimo 406 roller furling effort on my boat, and I'm having major trouble tensioning the thing.

It's the turnbuckle version, as pictured here http://www.seamarknunn.com/acatalog/info_PL25723.html

The problem is the metal prongs you can see at the bottom, don't allow for access to the bottle screw in order to turn it.

The backstay is equally floppy, but is tensioned as far as I can get it.

Any ideas?
 
On my Plastimo, which admittedly is a different model to yours, the metal prongs, which prevent base from rotating, are screwed into the drum. I unscrewed & released one side allowing room for a spike & spanner to adjust the bottlescrew.

Might be worth a look to see if that works for your model.
 
Solved it, but lost the use of my bow roller in the process.

Way back when, a shackle was added to the forestay in order for it to clear the bow roller. It meant the forestay couldn't be tensioned properly. How many miles I've done with it like that. Wells-next-the-sea to Stonehaven, to be precise.

Anyway, anchor can no longer stow on the bow roller, which is no bad thing I suppose. I'll just keep it in the chain locker and bring it out when needed, which is not so often.

Can't wait for a test sail now. See if she behaves better with a non-sloppy rig.
 
  • Asseess the amount by which the forestay bottle screw needs to be adjusted
  • support the mast with a halyard down to the foredeck
  • slacken the the shrouds, at least the aft lowers, a little and the backstay
  • disconnect the forestay and furling gear side plates
  • adjust the bottle screw by the amount you have assessed above
  • reconnect the forestay and the side plates
  • release the temporary support
  • adjust the backstay to give the required tension in the forestay
  • re-tension the other rigging

Repeat the above if necessary
 
You should not need a shackle in the forestay. Get rid of it and pin the bottom of the bottlescrew to an appropriate pair of holes in the side plates.
 
Tension on forestay

As Vic says (in different words) the turnbuckle in the forestay only sets the amount of mast rake. You use the backstay and shrouds to set the forestay tension. As such you might consider removing the turnbuckle if that will enable the reefing drum hence whole jib to sit lower closer to the deck. Lower means less heeling power from the jib or room for a larger jib and better seal in the bottom of the jib gap. (less end effect turbulence). On the other hand you can't see under the jib so easily. olewill
 
William_H said:
As Vic says (in different words) the turnbuckle in the forestay only sets the amount of mast rake. You use the backstay and shrouds to set the forestay tension. As such you might consider removing the turnbuckle if that will enable the reefing drum hence whole jib to sit lower closer to the deck. Lower means less heeling power from the jib or room for a larger jib and better seal in the bottom of the jib gap. (less end effect turbulence). On the other hand you can't see under the jib so easily. olewill
Click to expand...

I don't know if you are familiar with these Plastimo reefing spars They are relatively inexpensive and particularly aimed at DIY fitting... but they appear to be reliable and functional.

People do get into a tangle with them though, partly because there are two versions. One is designed to be fitted over an existing forestay and bottle screw without taking the mast down. The other to a new forestay without a bottle screw.
In most cases you would not be able to remove the bottle screw from the former type and even if you could it would not lower the drum.

Prompted by questions on here and by a question on our owners association forum I went round the boatyard a few years ago and photographed a few examples of how people had fitted them. You'd not believe how many different ways there are of fitting them incorrectly, or at least not as Plastimo intended.
 
Thank you chaps.

The plastimo furling came with the boat. The other models look a bit better, but I wouldn't buy the 406 given the choice. It's forever getting the furling line wrapped around itself. You have to keep a bit of tension on it at all times, or it gets knotted, so to speak.

Of course, this happens most often when you have the genoa up in an F6, and you're approaching a harbour entrance.
 
nathanlee said:
Thank you chaps.

The plastimo furling came with the boat. The other models look a bit better, but I wouldn't buy the 406 given the choice. It's forever getting the furling line wrapped around itself. You have to keep a bit of tension on it at all times, or it gets knotted, so to speak.

Of course, this happens most often when you have the genoa up in an F6, and you're approaching a harbour entrance.
Click to expand...

I think with any furling gear its necessary to keep the furling line under control while you unfurl the sail.

Problems with it jamming on the drum if not wound on tightly may be worse with lightish lines on small drums on gear fitted to small boats rather than being related to any particular makes.

Type of rope used for the furling line will have some effect as well. I'm not sure if a slippery rope is better or worse but what I do know is that the turns in a 3 strand rope lock themselves together with a vengence
 
I overstated the case a bit for emphasis but if you tension forestay instead of the backstay then you will remove rake which contributes to forestay tension however it also tensions the backstay.

Most furlers on sloop rigged boats don't have any adjustment on them as it is supposed to be a fixed length.

If you over do it you can get forward rake and will never get forestay tight enough as the weight of the mast will be slackening it off.

Its easier to tension backstays anyway so why not?
 
My solution to this problem was to cut the head off an M8 stainless bolt (on my "toy" lathe!) to give me a threaded bar about 4cm long. I then put the forestay into place with the bottle screw fully slack. This REALLY helps because the weight of the furler makes it sag and if the bottle screw is adjusted before hand it is all but impossible to reach the deck fixing. The threaded bar is then put into place to "pin" the forestay to the fixing but with no nuts put on. I then lifted the furler out of the way and tightened the bottle screw to the required position. Then it was simply a case of putting the chain plate end holes onto the bar, which you can't do with a conventional pin or a bolt, and locking two nuts on each side.
Worked for me, even if it doesn't look elegant, but I'd welcome any warnings about any danger I might not have thought of. It's certainly safer to my mind than doing what half the boats I see have done, which is bolting the chainplate halfway up the bottle screw. That has to be a disaster waiting to happen!
 
My solution to this problem was to cut the head off an M8 stainless bolt ..................
Click to expand...
It sounds sensible solution. Far more sensible than some of the bodges I've seen.

It would perhaps be be preferable to use a short piece of round bar just threaded on both ends so that all the loads were taken on the unthreaded section. You could make that from a bolt rather than the setscrew I guess you used

However I dont see the objection to the bottom of the bottle screw being fastened to one of the lower pairs of holes in the side plates (and the lowest pair used to fasten the side plates to the stem head fitting). Its not 100% clear but that appears to be what the assembly instructions show, with the version that does not retain the bottle screw the end of the forestay being fastened to the upper pair of holes.
A screw and a nut secure the foretay or the bottom of the bottle screw to the side plates and a clevis pin , washer and split pin secure the side plates to the stem head.
 
VicS said:
I think with any furling gear its necessary to keep the furling line under control while you unfurl the sail.

Problems with it jamming on the drum if not wound on tightly may be worse with lightish lines on small drums on gear fitted to small boats rather than being related to any particular makes.

Type of rope used for the furling line will have some effect as well. I'm not sure if a slippery rope is better or worse but what I do know is that the turns in a 3 strand rope lock themselves together with a vengence
Click to expand...

I am not a fan of furling however I really wonder why the manufacturers have not gone for electric drive furling. This would be so much more positive and easy. I see some many cheaply made electric drives on cars radio aerials, windows, door locks seat adjustment etc. I wonder why it can not be easily done with a motor and worm drive. I have seen huge hydraulic drives but small for small yachts should be easy. Or are they already available? I could be tempted one day when I get old....olewill
 
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