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Can anyone tell me how often the Beam Lashings between the hulls have to be replaced on a Wharram (boat is in West Indies) Also, is there any particular rope that should be used? Oh, while I'm here...Is it possible to use stainless steel cable instead of rope for the steering lines? Thanks.

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First of all, I've neither built nor sailed a Wharram as yet, but for what it's worth:

The beam lashings doesn't seem to need to be changed all that often. You do need to watch them to make sure, but from what I've read it's on the order of 'once every couple of years' that you need to change anything.
Perhaps a more reliable source than me can confirm this..

As for the rope:
Yes, it will need to satisfy some very specific criteria.
Offhand, I can think of elasticity, tensile strength and friction as important factors; add to that uv- and saltwater resistance.
You also need to select the correct thickness of rope.
Wharram has recommendations of rope choice - I think it's specific to the particular model of boat, so you need to tell us which design you're asking about.

Thank You Uffe W, The boat is a Pahi 42. The lashings have not been replaced for over four years now so are long overdue for replacement if the boat is to cross an ocean then?. As I don't have the  plans I have no idea how long each lashing is either. 

The replacement rope should not be pre-stretched then? Nor any rope that won't have elasticity? Not braid then? No rope that would normally be used for running rigging, ie Halyards & Sheets.

The lashings are intended to absorb some of the forces between hulls and beams, so at least some elasticity is required I think.

The rest.. I don't know, sorry :]

John, you do need pre-stretched or low stretch rope, the sort of thing that would be used for halliards on dinghies etc.  I think from recollection the ones on my Tiki are 16 plait braid, polyester core and sheath.  While it's true that the lashings need to absorb shocks the small amount of elasticity in these ropes is enough. Go for a well known make that you can trust, not something bought at a jumble sale.  I'm not sure about using exotic high tech rope, have a look around the forum and you'll probably find previous discussions on that subject.  You need to get the lashings very tight so there's not enough movement to cause any chaff.

As for how long they'll last, the answer is "it all depends"...  The important thing is to check them thoroughly and regularly and replace any that show signs of wear or damage.  At four years old they may or may not need replacement, but it's not a particularly expensive thing to do anyway.  You'll find some people on this forum who've done many many years on the same set of lashings.

Regarding replacing the rope steering lines with stainless steel, are you sure you want to?  Stainless steel is vulnerable to fatigue and corrosion which can cause sudden failure, whereas most types of rope only suffer from wear.  If the rope system is set up properly and checked regularly you shouldn't have any problems.  You do have to be a bit more careful with some of the special high-tech ropes though, as they can snap suddenly without warning just like wire (It happened on a Pahi 52 I was on in the middle of the Indian Ocean).  If you do want to change to stainless steel you'll have to change all the sheaves and possibly other parts as well.

Regards

Rob

Thanks Rob, much appreciated.

Thanks.



Uffe W said:

The lashings are intended to absorb some of the forces between hulls and beams, so at least some elasticity is required I think.

The rest.. I don't know, sorry :]

I agree with everything robert has said.

And I would like to add that the lashings should be as tight as possible and checked regulary. Tying them is not the work I like most but the lashings are one of the most important parts of the construction. We had one or two lashings too loose in the beginning and there was some movement between hull and rear beam. This caused minor damage to the beam. Properly tightened lashings were much better. The force of the waves will easily move the hulls also with very tight pre-streched ropes. 

I have a Pahi 42 and use 8mm braided line. Each lashing is about 10m long. However tight the lashings are, you will still see movement - that is the idea, but it can be a bit alarming to see! On our boat we use push-pull cables for the steering, the type used for big outboards. As each rudder has its own cable, there is built in redundancy in case one breaks. When I bought the boat she had a pretty strange steering set-up so I had to change it anyway. I don't think it would be a good idea to use ss wire for the steering - rope is much easier to work with if you need to replace it while at sea. If you are going to keep the boat in hot climes then I think it would be essential to replace lashings and other ropes much more frequently - I've got no experience of this (being in the Baltic!) but I'm sure others can advise.

Makes good sense, Thanks. Now I have another question!...What are Wharram owners doing about hot water for a shower? (Yes, I'm a wimp! I like at least some warmth in the water) How many options are there for heating water on a Wharram? What are other owners doing?

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