Rigging bowsprit whisker stays

[westernman]

At the moment my 18ft bowsprit has fixed whisker stays (i.e. attached with bottle screws) which makes it impracticable to ship and unship for parking in my marina berth.

I am considering shortening the stays and replacing the bottle screws with a tackle which can be easily let off or tightened up from the deck.

The idea being of course so that I can unship the bowsprit when berthing which would allow me to park bows to in my normal parking space. This would be much safer with the stern to the prevailing storms rather than the bow. Also parking in reverse is difficult at the best of times and really difficult in a strong cross wind blowing the bows off.

What is the working load on the bowsprit whiskers?

How much purchase is really needed? At the moment I am thinking of 4:1 using a single block at the aft end and a violin at the other with the line coming back on board form the violin block.

I am also looking for suitable blocks for this, and I reckon some galvanized blocks would be best suited for this. Any pointers for a suitable supplier?
I guess some of rigging suppliers for the building industry are probably a better bet than the swindleries.

Thanks in advance for ideas, advise etc etc.

 

[prv]

Can't help with the loads, but I thought it worth mentioning that my bowsprit shrouds use over-centre levers (Highfield style) and so don't suffer from the stretch you might get in a tackle. All they do is relieve the tension so that I can get the fid out and slide the sprit aft.

Any number of reasons this might not be appropriate on your boat, but something to consider.

Pete

 

[DownWest]

Apart from talking to Covey Island, might you use the size of the wire as a starting point for the load?

 

[westernman]

Apart from talking to Covey Island, might you use the size of the wire as a starting point for the load?

I suspect that the wire is vastly oversized and just happens to be a convenient size. It costs practically nothing to do that.

However, any kind of pulley has a safe working load which will be considerably less - hence the question for some kind of ball park idea.

Probably the designer, Ed Burnett will have an answer, rather than the builder. Thanks for prompting the idea.

 

[prr]

michael, you park cars not a boat! An 18 ft bowsprit needs to be able to be reefed in heavy weather for safty reasons, not just for parking.

 

[DownWest]

Forget the name, but those guys in Canada who sell plastic dead eyes and synthetic rigging might be usefull. It is not as if you need to stress up the stays under load. Static heaving would be enough. The load is only under sail.
'cours, bits of plastic might offend the look.......
Gaff Rig Handbook suggests 3:1 blocks (for old fishing vessels) so 4;1 with modern rope might be sound? Blocks would be very close to each other to avoid stretch. I quite like the highfield lever idea. But were might one find them?
A

 

[westernman]

The bow sprit stays are dimensioned for 10500 lbs breaking strain, the bobstay for double that.

I don't think there are pulleys which are that strong though.

 

[DownWest]

The bobstay is taking a big load. The wiskers rather less, and not half by quite a bit. As you say, the wire is probably over the top. A chat with Burnet would solve it.
A

On a rather smaller gaffer, I was hauling it round in shallow water and grabbed the wisker. It came away in my hand as the splice failed. Clearly not doing a lot. Yours is much bigger, but I don't think the loads are huge.

 

[westernman]

Can't help with the loads, but I thought it worth mentioning that my bowsprit shrouds use over-centre levers (Highfield style) and so don't suffer from the stretch you might get in a tackle. All they do is relieve the tension so that I can get the fid out and slide the sprit aft.

Any number of reasons this might not be appropriate on your boat, but something to consider.

Pete

Can you show us a photo of those?

I know of highfield levers used in other situations but I don't quite see how they would be rigged for this.

 

[Seanick]

I have just gone through this process.
My bowsprit is 25'7" long, with 19' outboard. I was tired of tensioning the leward lashings to get the shrouds tight.
I fitted to the 10mm shrouds 14mm Tufnol blocks, 5:1 ratio reeved with 10mm Vectran line.
So far so good.
Then we had this race with 38knts. Yes of course we had everything up....the Tufnol blocks (rated at I think just under 2tons) parted and the bowsprit neatly dissapeared.

I now have a new bowsprit which will have some nice big bottlescrews on!
There are blocks (ash/bronze) available with a higher rating but they are about £200 each.
I will probably make my own with ss cheeks eventually. I am also adding a spreader on one side to reduce the load and increae the staying angle.

I obviously underestimated the loads that a 450 sqft heads'l develops!

 

[westernman]

I have just gone through this process.
My bowsprit is 25'7" long, with 19' outboard. I was tired of tensioning the leward lashings to get the shrouds tight.
I fitted to the 10mm shrouds 14mm Tufnol blocks, 5:1 ratio reeved with 10mm Vectran line.
So far so good.
Then we had this race with 38knts. Yes of course we had everything up....the Tufnol blocks (rated at I think just under 2tons) parted and the bowsprit neatly dissapeared.

I now have a new bowsprit which will have some nice big bottlescrews on!
There are blocks (ash/bronze) available with a higher rating but they are about £200 each.
I will probably make my own with ss cheeks eventually. I am also adding a spreader on one side to reduce the load and increae the staying angle.

I obviously underestimated the loads that a 450 sqft heads'l develops!

That makes the 10500 lbs breaking load sound reasonable.
And yes, finding blocks for that load is not easy (I have not found any yet). I would not have chosen tufnol blocks though. I have galvanized steel blocks on the bobstay and I would like to put something similiar on the stays.
Isn't the spreader going to be very liable to damage when docking?

May be the highfield lever is the better way to go?

I have 18ft outboard - so about the same dimensions as yours.

 

[Seanick]

I had a close look at your bowsprit set up. I think your galv blocks are custom made as I dont reconise the pattern. That may be the easiest route for you. Get the cheeks laser cut and buy or make the sheaves.
Daveys do some hefty blocks, but I don'tthink they are rated for 5 ton. Spencers rigging or Colin Frake or Martins Rigging may have some ideas though.

Westernman had a spreader-Tom says no probs!

I don't really like the look of highfields-there a bit 1950's!

 

[westernman]

Spencers rigging or Colin Frake or Martins Rigging may have some ideas though

Any other pointers for riggers likely to have some decent pulleys?
I have checked the websites for those above but can't see anything suitable.

Thanks.

 

[Seanick]

Give them a ring-the websites represent a fraction of their services and knowledge.

try

www.maritimeiow.co.uk/

or

http://tsrigging.co.uk/

 

[prv]

Can you show us a photo of those?

Don't have one to hand...

Bear in mind that my boat is both considerably smaller than yours, and fibreglass. So it was just the idea of using levers I was proposing, not an exact duplicate of the setup.

What I have is a manufactured lever fitting about 8 inches long - the sort of thing you might have as a tack tensioning device on a Wayfarer. Somewhat similar to this although the base adjustment is pin-through-one-of-several-holes rather than the ratchet style shown. The boat has quite broad toe-rails, and the lever is simply mounted on top. The bowsprit shroud has an eye in the end that goes over the hook, and I also have a short lanyard between the eye and a nearby stanchion, to retain it nearby when it falls off the hook when slack.

If you decided to go this route on your boat you'd probably be looking at something from Classic Marine's backstay range, I guess mounted on the covering boards at the foot of the bulwarks and leading the wire underneath.

Pete

 

[Woodlouse]

Whisker shrouds don't have to be that strong. A 5 ton breaking strain is ridiculous for a spar that would probably surprise you in it's ability to support it's self. Pilot cutters originally didn't have whisker stays, though their bowsprits were generally only 10 or 12 feet. Personally with a 35 foot gaffer we have the whiskers on a 12 foot sprit lashed with 6mm three strand.

Boats I've seen with tackles on the stays generally have either 3 or 4 to one purchases on standard 3 or 4 inch sheaths, with three strand ropes around the 15mm mark. You say you already have the innards for the blocks, so just give them to a shipwright and he'll knock out the bodies pretty quickly.

The size and strength of the wire you have will most likely be for cosmetic reasons. And there is a lot to be said for visual assurance in rope and wire, if weight isn't really an issue, like on a gaffer, then there is no harm is going for something that looks right even if it's massively over rated for the job in hand.

As for tension that doesn't have to be too great either. You don't need it to be bar tight as a moderately tensioned wire will take all the strain required once the load comes on a the bowsprit bends slightly. Wood is surprisingly flexible and a slight bend will cause no harm.

 

[Carlotta]

The tackle we use has a double-becket double block in front and a single-becket double block aft. The hauling part leads from the forward block through the scuppers and belays on the first pin on the rack inside the rail.
I was going to fore-go rigging whisker shrouds altogether (as many pilots didn't use them - or bobstays either!) , but decided I didn't want the stem ripped out of the boat by the bowsprit...

 

[westernman]

The tackle we use has a double-becket double block in front and a single-becket double block aft. The hauling part leads from the forward block through the scuppers and belays on the first pin on the rack inside the rail.
I was going to fore-go rigging whisker shrouds altogether (as many pilots didn't use them - or bobstays either!) , but decided I didn't want the stem ripped out of the boat by the bowsprit...

Where did you get the blocks from?

Some one earlier in this thread broke his blocks which had a 2 ton working load with a 450ft headsail. I have a 1183 sq ft reaching genoa!

 

[Seanick]

Where did you get the blocks from?

Some one earlier in this thread broke his blocks which had a 2 ton working load with a 450ft headsail. I have a 1183 sq ft reaching genoa!

My blocks that broke were rated to break at just under 2 tons, not SWL.

It would be interesting to put a load cell into the rig and go for a sail.

My reacher is 1200 sqft, but does not load the sprit as much as when hard on the wind.

Found any blocks yet?

 

[Carlotta]

Where did you get the blocks from?

I rebuilt some old ones that were with the boat. They have iron strapping and I rebuilt them with ash cheeks.

Try here if you can't find any where you are:
http://www.bluenose2.ns.ca/Catalogue/Marine/Blocks.html
Made by A. Dauphinee & Sons, Lunenburg, Master Blockmakers to the tall ships of the world.