Another Kemp Boom Question

[Praxinoscope]

The outhaul on my Kemp boom (circa 1980) has been getting stiffer to use and I suspect that the internal traveller is causing the problem, so I want to service it this winter, it looks as if I have to drill out some pop rivets to gain access, I'm guessing that the traveller is nearer the 'gooseneck' end of the boom, but haven't found and drawings to confirm this, has anyone had to do this work on their Kemp Boom?
Photos of both ends are attached if they help to identify the boom.

 

[vyv_cox]

I have drilled out the rivets at the aft end on two booms to fit single line reefing. Easy to do. I replaced the rivets with Rivnuts, enabling future removal straightforward.

 

[pvb]

If you look at the Seldén website, you can download manuals for early Seldén booms, which are similar in design to your Kemp boom. The diagrams may help you sort out the traveller. This manual is a starting point:-

https://www.seldenmast.com/files/1426855957/595-081-E.pdf

 

[Praxinoscope]

Vyv and pub
Thanks for replies, I was wondering about either tapping the casting or fitting rivnuts to avoid using pop rivets again. I had looked at the Seldon diagrams, none of them quite matched and I don’t want to pull it all apart and find a nasty surprise.
I was happy with the system on my previous boat where the outhaul was just a rope around a pulley and then coming out of the boom to a cleat, this arrangement just seems to make life difficult to no advantage.

 

[pvb]

I was happy with the system on my previous boat where the outhaul was just a rope around a pulley and then coming out of the boom to a cleat, this arrangement just seems to make life difficult to no advantage.

And they can rattle! I took the end off the boom on my old HR and wrapped the traveller in foam to stop it rattling.

 

[vyv_cox]

For some reason mine never had the 2:1 outhaul, just a continuous line. Needs to be tightened with the winch but no problem doing that.

 

[BabaYaga]

Vyv and pub
Thanks for replies, I was wondering about either tapping the casting or fitting rivnuts to avoid using pop rivets again. I had looked at the Seldon diagrams, none of them quite matched and I don’t want to pull it all apart and find a nasty surprise.
I was happy with the system on my previous boat where the outhaul was just a rope around a pulley and then coming out of the boom to a cleat, this arrangement just seems to make life difficult to no advantage.

I serviced the outhaul of my 1980 Selden boom last winter. (Cannot open you attachments, so not sure if mine is similar to yours).
What I found was a 4:1 tackle, as you suspect, rather close to the goose neck. The tackle line was anchored to the goose neck casting, on the same axle was also a small sheave, probably tufnol. At the other end of the tackle was a common fiddle block, connected to a stainless wire with the outhaul at the aft end.
The main reason for stiffness was the tufnol sheave not turning on the axle, had probably swelled over the years.
I replaced sheave, axle and tackle line, everything runs fine now.
I also thought about tapping, but in the end decided not to. The rivets goes into holed ’tabs’ that are part of the casting, they locked a bit too fragile for tapping, so just replaced with new monel rivets.

 

[William_H]

I doubt the boom has a traveller like a main sheet traveller but as described a 2 to one 3 to one or 4 to one tackle inside the boom. Yes a recipe for friction and problems. So you need to remove the fittings on the boom. Easy to drill out the pop rivets but likely difficult to free the fitting from the tube. Worse case you may have to cut the boom tube and shorten it a bit. So check before you start that you can shorten it. However try the hot water and other remedies for corrosion.
As said for smaller boats a bit of spectra rope passed through the eyelet on the clew and back to a saddle will give an external 2 part purchase which with the aid of a winch on cabin top might be suitable. I found that a tackle just makes it very difficult to free the foot for light conditions. ol'will

 

[adamlang]

The outhaul on my Kemp boom (circa 1980) has been getting stiffer to use and I suspect that the internal traveller is causing the problem, so I want to service it this winter, it looks as if I have to drill out some pop rivets to gain access, I'm guessing that the traveller is nearer the 'gooseneck' end of the boom, but haven't found and drawings to confirm this, has anyone had to do this work on their Kemp Boom?
Photos of both ends are attached if they help to identify the boom.

How did you get on with the actual outhaul Praxinoscope?

I have pretty much the same boom and problem that I'm about to start looking into. The outhaul car that you can just see in the my photo is really stuck. I'm wondering if the car is meant to be attached to the outhaul wire strop externally, rather than attached internally as is presumably the case. I'll find out more when I take the end off in the next few weeks, fortunately the aft end at least is attached with hex bolts rather than rivets.

 

[Poecheng]

How did you get on with the actual outhaul Praxinoscope?

I have pretty much the same boom and problem that I'm about to start looking into. The outhaul car that you can just see in the my photo is really stuck. I'm wondering if the car is meant to be attached to the outhaul wire strop externally, rather than attached internally as is presumably the case. I'll find out more when I take the end off in the next few weeks, fortunately the aft end at least is attached with hex bolts rather than rivets.

I have a Kemp boom which I have been looking at recently. The central sheave on the boom end should be for the clew outhall and, on mine, a wire comes out and attaches to the aft end of the outhall car, which should slide freely. It is tensioned by the central line at the gooseneck end.
I have found a Kemp rigging owner's guide in my papers which, if you like, I can scan for you at the weekend if you PM me to remind me.

 

[adamlang]

Thanks Poecheng, that's helpful and a nice offer. I'm not really sure what I'll find inside having seen various designs and it may of course have been modified since it was built. So any sort of guide would be really helpful, thanks. Though I'll not be getting to this for at least two weeks, so no rush.

Our boom seems a bit different to yours in that the outhaul line comes outside of the mast on the starboard side about halfway and goes through an old style jammer (also thinking of replacing that). Its meant to be pulled aft to tighten the outhaul so it at least goes through a couple of blocks. The fact that its not on a winch like the reefing lines means that I might need to update/improve whatever sort of purchase is in there. I think the seized car might be just the start of the problem.

Thanks,

 

[Poecheng]

Thanks Poecheng, that's helpful and a nice offer. I'm not really sure what I'll find inside having seen various designs and it may of course have been modified since it was built. So any sort of guide would be really helpful, thanks. Though I'll not be getting to this for at least two weeks, so no rush.

Our boom seems a bit different to yours in that the outhaul line comes outside of the mast on the starboard side about halfway and goes through an old style jammer (also thinking of replacing that). Its meant to be pulled aft to tighten the outhaul so it at least goes through a couple of blocks. The fact that its not on a winch like the reefing lines means that I might need to update/improve whatever sort of purchase is in there. I think the seized car might be just the start of the problem.

Thanks,

View attachment 98850

That doesn't look standard. It may be they have done that so you have three reefing lines through the boom itself rather than a central outhaul and a reefing line either side.

 

[adamlang]

Not surprised at all if it isn't standard, boats seem to be like that, particularly older ones. It's a Contessa 34 OOD btw, a racer cruiser. Built 1980ish.

We only have two reefing lines fitted, both run to the mast and down to a winch solely for the reefing lines. I'm almost certain the middle sheave at the aft end is taken up with a wire that's for the outhaul, but unlike yours and the OP it runs internally to the car. I think at the mast end there's only two sheaves, I'm fairly sure there's only two of those in-built rope clutches. Would be nice to have three permanent reefing lines though - we rarely rig the third reefing point on the mainsail.

 

[Poecheng]

Not surprised at all if it isn't standard, boats seem to be like that, particularly older ones. It's a Contessa 34 OOD btw, a racer cruiser. Built 1980ish.

We only have two reefing lines fitted, both run to the mast and down to a winch solely for the reefing lines. I'm almost certain the middle sheave at the aft end is taken up with a wire that's for the outhaul, but unlike yours and the OP it runs internally to the car. I think at the mast end there's only two sheaves, I'm fairly sure there's only two of those in-built rope clutches. Would be nice to have three permanent reefing lines though - we rarely rig the third reefing point on the mainsail.

Others on here have vastly more knowledge/experience but I have recently been dealing with my boom so am very familiar with it. Mine is for a smaller boat (1983) but not sure whether it will be different save for dimensions.

I would be surprised if you only had two positions/sheaves at the gooseneck end of the boom - not least because you will have three at the other end.

Also, as I explain below, the fact you only have two jamming levers does not mean you have only two sheaves at the gooseneck end.

At the gooseneck end, mine has two movable levers that act as jammers (as you have described on yours) and these are on either side and lead to 'reef 1' and 'reef 2' at the aft end (you see those words cast in the side of the boom end fitting)

However, there is also a central sheave for the outhaul. This doesn't have a jamming lever. Where the outhaul exits underneath the boom, it is pulled towards the aft end of the boom through a wedge shaped opening/outlet. To tension/jam it you pull it aft and then downwards so that it locks in the wedge. It doesn't have a jamming lever but does have a locking facility that is under the boom and doesn't sit proud of the boom but is, I think, within the track on the underside of the boom. You have a reefing winch so the arrangement might be different but may be worth checking what is there underneath the gooseneck end, particularly if you have not had a central rope to make you look as keenly

Not sure how the outhaul wire runs from the boom end sheave internally to the car unless there have been some major modifications - it would mean the bottom of the bolt-rope channel would be split so that the outhaul car can be operated from underneath (which would result in an unusual angle of pull). The ones I have seen online in addition to mine have a wire loop that exits the boom end, goes through a small guide that is rivetted to the top of the boom and then to the outhaul car.

I am guessing now but I reckon you can get your outhaul set up as described (but with string not wire) so that, if you get clunked by the boom on the side where your outhaul jammer presently sits, it only moderately hurts rather than leaving a lasting impression.

As said, others are vastly more knowledgeable and I am not familiar with the set up of racers.

 

[Poecheng]

Here is the owner's manual for Kemp rigging and at a time when they had been taken over from Selden. This would have come with a 1983 boat.

 

[adamlang]

Thanks, that's helpful. I had hoped for a little more detail on the outhaul, but the various Selden guides should provide me with an idea of most options/ideas. The information on the mast is useful too.

I've ordered a length of 5mm dyneema to make up the internal lines as I expect that the old wire in there will need replacing.

 

[BabaYaga]

Thanks, that's helpful. I had hoped for a little more detail on the outhaul, but the various Selden guides should provide me with an idea of most options/ideas. The information on the mast is useful too.

I've ordered a length of 5mm dyneema to make up the internal lines as I expect that the old wire in there will need replacing.

With a Seldén/Kemp boom from circa 1980, my guess is your will find the outhaul tackle look something like in this photo below.
It shows my boom (from 1980) with the gooseneck casting removed. Unless the stainless wire is frayed where it goes around the sheave, I doubt it will need to be replaced. If the outhaul is difficult to operate, more likely that the rope that make up the tackle is worn or sheaves not running smoothly.

 

[Poecheng]

Found this as well which explains a bit more

 

[adamlang]

Thanks both that's really helpful. I'd be happy if I can get away without drilling the rivets at the mast end. Running a new line seems fairly straightforward, but...

Baba Yaga, is that the outhaul line anchored with a splice loop, to the gooseneck casing, just behind the block in the photo? Was wondering where it was anchored. Other end presumably attached to a becket on the other block.

Looks like I'll have to take both ends off. I'll take my drill. And think about tapping holes for hex bolts.

 

[BabaYaga]

This photo shows the gooseneck casting removed from my boom, with the outhaul tackle still attached.
There is a 10mm (IIRC) aluminium shaft on which the tackle line is anchored by a loop. In the middle slot there is a tiny sheave that form part of the tackle. In my case I found that this sheave did not spin on the shaft, the main cause for the poor performance of the outhaul. The line was not too worn, but I changed it out anyway, as I don't intend to take the casting off for some time to come...