How many lashings and what line and size?

[Jim Jimbo Beyer]

Hi All,

I need to know the number of lashings and what type of line and what size of line to use.

I am refitting my friends' 43' Narai "Windchime"

I have rebuilt the bulwerks, reglassed the decks and cabin tops, replaced the steel beams with 2' wider ones and now I am getting close to being finished. The last coat of Awlgrip has been applied and now it's time to fit the beams in permanently.

Can anyone share with me the appropriate lines and sizes I should use. I don't have the original lines that I removed when starting the project to use as a reference.

Thank you all in advance.

Jimbo

[Robert Sheridan]

Off hand can not not help; however, there has been a few discussions on this so if you have not done so it would be worth doing a search.

Robert

[Andy Best-Dunkley]

Hi - I have a Pahi 42. For lashings we use about 10m of 8mm pre-stretched multibraid line, although I am planning to downsize to 6mm as it seems to stay tighter longer (can get more purchase when tightening it). I haven't seen a Narai for a very long time so can't be more specific.  I have original style pahi beams, so with a big bolt through the beam trough locating them in place, as well as the lashings.

Andy

[Jim Jimbo Beyer]

Thanks Andy,

This Narai has steel beams with eyebolts below. I have widened the boat by two feet. The original line was 3/8 or 7/16 I recall. How many "wraps" does the 10M of line get you. If I remember correctly, this boat had seven "wraps".

Jimbo.

Andy Best-Dunkley said:

Hi - I have a Pahi 42. For lashings we use about 10m of 8mm pre-stretched multibraid line, although I am planning to downsize to 6mm as it seems to stay tighter longer (can get more purchase when tightening it). I haven't seen a Narai for a very long time so can't be more specific.  I have original style pahi beams, so with a big bolt through the beam trough locating them in place, as well as the lashings.

Andy

[wakataitea]

???? down size to 6mm on a 40 feet boat... good luck... if you don't get it tied enough, then we should work on your lashing technic. the tiki46 has 10mm rope and 6 turns. with 6mm and 20 turns, you create only a big rope bundle and the tention will be on a few strings....

[Andy Best-Dunkley]

Well thanks for your comment, but I'm not sure I agree with your criticisms...! ;-) (but can be convinced, I have not changed the lashings yet). The 6mm sits very well and stays tights, strain is on ALL of the turns, while I find with the 8mm I can't get the same tightness on all turns. Yes, maybe my technique can be improved - any tips?! These ropes are incredibly strong anyway, so multiple turns of a thinner line is not necessarily any weaker if there are a few extra turns.

[Don Brazier]

A Narai IV built in South Africa and sailed to Australia some years ago had 6 mm lines lashing the beams down

I have used 8 mm on my Narai IV

You mentioned that there are eye bolts under your beam , did you mean the lashings go through these eye bolts?

Don

[Jim Jimbo Beyer]

Yes Don, two eyebolts at each lashing point.

What "kind" of like does everyone recommend?

-jim

Don Brazier said:

A Narai IV built in South Africa and sailed to Australia some years ago had 6 mm lines lashing the beams down

I have used 8 mm on my Narai IV

You mentioned that there are eye bolts under your beam , did you mean the lashings go through these eye bolts?

Don

[Don Brazier]

The Wharram Plans for the Tiki 46 call for six turns of 10mm prestretched braided polyester line , while the Tiki 38 plans call for six turns of 8 mm 

The Narai IV is between these two boats in size although the hulls are wider  which may affect leverage on the beam lashings??

The Narai was originally designed with rubber blocks and galvanised bolts to secure the beams to the hulls but there is now a modification sheet available from  Wharram Designs which  gives the option of Tiki style beams and a lashing system.  James and Hanneke advise 10mm prestretched braided polyester for the Narai, Ariki and Tehini designs if modified.

The eyebolts under your beams are a different idea  and keep the line out of the sun !

I can understand a greater difficulty tightening 10 mm line through an eyebolt than round a beam,  also there must be  downwards and sideways stress on the eyebolt after tightening the frapping lines.   

The other question I was going to ask is whether there is plenty of room for the frapping lines when tightening the lashings ?

Although I mentioned 6 mm line being used on a Narai IV in an earlier post , I was just reporting this fact not advocating it.

When each  lashing area is  first installed it is unlikely that each turn  will all be tensioned to exactly the same tension so some very slight movement and evening out must occur and sometimes further slight tightening of the frapping may be needed after a while.  Also the line may stretch to a small degree.  There was an earlier thread discussing this.

Don

[Andy Best-Dunkley]

Just to report that after this summer's experiences I will NOT be changing down to 6mm line for the lashings! Not that anything happened to the one lashing that is currently 6mm, but I spent a lot of time watching the beams and hulls in various sea states and could see that the forces excerted are huge, even if momentarily. So 8mm and keep them tight!

Andy

[Roger]

I don't know if anyone has posted this already, but this seems an appropriate spot.

http://forums.sailinganarchy.com/index.php?showtopic=154025

This an extremely useful thread on SA about load testing of knots and splices in dyneema and other materials. One of the interesting insights is that there is close to zero load on individual lashings if there is enough windings, and if the windings are taking an equal load.

The tensile strength of 1/4 dyneema is 8,600 lbs, which is more than 8mm double braid. It is also much more abrasion resistant than double braid. On my own little boat (Tiki 21) I have gone down to 1/8 dyneema and found that it winds and "sits" better and is very durable. The previous windings using nylon were much more vulnerable to abrasion even though they were thicker.

[Robert Sheridan]

I tried using thin spectra (about2 or 3 mm) for our shroud lashings as I did not have much space to put the lashings through.  However, When taking it off we found it had frayed and I suspect that the thinner lines are less durable if there is anything for them to rub on (in our case hard eyes).

Roger said:

I don't know if anyone has posted this already, but this seems an appropriate spot.

http://forums.sailinganarchy.com/index.php?showtopic=154025

This an extremely useful thread on SA about load testing of knots and splices in dyneema and other materials. One of the interesting insights is that there is close to zero load on individual lashings if there is enough windings, and if the windings are taking an equal load.

The tensile strength of 1/4 dyneema is 8,600 lbs, which is more than 8mm double braid. It is also much more abrasion resistant than double braid. On my own little boat (Tiki 21) I have gone down to 1/8 dyneema and found that it winds and "sits" better and is very durable. The previous windings using nylon were much more vulnerable to abrasion even though they were thicker.

[david coe]

We are the original builders of Windchime. We used 3/8" line, and found that using nylon was the best type to use as it stretches and then rebounds, where as other synthetics, once they stretch, do not return and then hang slack much sooner than nylon did. We have been in St James city many times, still have friends living in the area, and Windchime was at Bob & Annies, as it was known, a few times. BTW we had increased the beam by 2' when we built her in the late 70's early 80's in Toronto. Got any pics of her now?

david & neila