Boom Upgrades

[Capricious 22]

So now that the boom is relaxing in my garage, I'd like to address some issues.

Cleats on the boom are terrible. The topping lift is good for decent scare and the other ones aren't much better. Is there a drop in that actually works?

My outhaul did not work when we bought the boat. I think half of the boom internals are missing. I removed the other half and just tied the line to end of the sail. Obviously, with no mechanical advantage, adjusting the outhaul is a feat of strength. I saw an upgrade in past threads, I'll probably install that.

I replaed the broken pin, that was plastic, with the metal pin from Catalina Direct. Much better.

Any other upgrades I should consider? I like drooling over the Harken Catalog.

 

[Richard9547]

This was the 4:1 upgrade I did on my Capri 26. (corrected ratio)

Might not need as much mechanical advantage on the 22.
And I don't see how to drop the outhaul line out the bottom of the boom (gooseneck) on the 22.
But it could be a starting point?

 

[Capricious 22]

Thanks for the drawing. That's basically what I had in mind.

It looks like Defender has replacement aluminum cleats that will fit the boom.
http://www.defender.com/product3.jsp?path=-1|118|2259990&id=74686

 

[drewlamparello]

Check out the Capri Drawings in this post... viewtopic.php?f=29&t=555

 

[NewportNewsMike]

Not sure how much mechanical advantage is needed to really crank in the outhaul when the wind really picks up. I do not know if it takes 4:1, 8:1, or even more.

The reason I bring this up is that the "8:1" setup in Cavelamb's sketch is really a 5:1 setup.
The the setup in the Capri 26 .pdf is a 8:1 setup. What makes it a 8:1 is the extra MOVEABLE block in series. (Its a 4:1 connected to a 2:1, which means total is 4 x 2, or 8:1.

The simple way to tell what the mechanical advantage of a "system" is, is to count the number of lines running to / through the moveable block.
Four lines = 4:1, five = 5:1, etcetera.

If there are two "systems" hooked in series, the total advantage is equal to the two advantages multiplied together.

In any event, I have a 4:1 setup that was originally posted here on the old forum by Dean Drevlow (White Lightening #110) a few years ago. His drawings called it a 8:1 setup, but is only a 4:1. I will try to find the older info and post it here. It has been a good systems, I have never used it in really heavy winds.

 

[NewportNewsMike]

Here is the post mentioned above. The sketch is mis-labeled "8:1", it is actually a 4:1 system. The sketch is not nice and sharp but it is the best copy I have. What makes the whole thing doable as sketched is the 90* fixed block.

by ‪Reverand » Thu Sep 02, 2004 1:00 pm
Last winter, three of us replaced our original outhauls with new blocks and lines. We modeled the upgrade on a successful conversion pioneered by Madcap, hull #5. The attached diagram by Jamie depicts the new schematic.

For hardware, we used the following:

Qty Description Item # Size
1 Harken 29mm Carbo Block - 90° Loop Single H352
1 Harken 40mm Carbo Fiddle H2655
8 Amsteel 12 - Red SMS12 1/8"
24 Amsteel 12 - Red SMS12 3/16"
2 Heavy-Duty SS Thimbles LSEY185 3/16"

The part numbers are those out of the APS catalog (‪http://www.apsltd.com) You can substitute 3/16” line for the 1/8”. This will make the splicing easier. When finished with the assembly, don’t worry about the extra line, easier to flub a couple splices, cut off and try again, than run short.

The hardest part is replacing the Boom Pin. For this little operation, I took two ¼” dowels, wrapping a rubber band about 12” from the end. Using the dowels like chopsticks, I was able firmly hold the Harken 29mm 90 degree block (with splice). We then placed the boom on its side between two sawhorses. Shining a light from below, you can then gently slide the chopsticks into the boom, line up the hole with the block, and drop in the Boom Pin. The chopsticks will then easily slide off the Harken block.

Including disassembly, splice time, and re-assembly, we averaged about an hour per boom for the upgrade at our little Boom Party.

Dean Drevlow
White Lightning #110
1985 FKSR

 

[NewportNewsMike]

Here is the sketch from Dean, White Lightning, #110

 

[jerrymlewis]

I think it is labelled correctly. there is a 4:1 advantage between the end of the line (toward the mast) and the existing wire block at the boom end. But with this turning block at the boom end, you actually double the advantage to 8:1.

At least that is how I understand these things to work/get counted.

 

[NewportNewsMike]

I think it is labelled correctly. there is a 4:1 advantage between the end of the line (toward the mast) and the existing wire block at the boom end. But with this turning block at the boom end, you actually double the advantage to 8:1.

At least that is how I understand these things to work/get counted.

The "turning block" at the end of the boom does just that - it "redirects" the angle of the pull. Only MOVEABLE blocks add to mechanical advantage. FIXED blocks (like the one on the end of the boom) only redirect force, they do not add mechanical advantage.

An easy way to prove this to yourself is to imagine pulling on a system of "blocks and tackle" . If you are pulling the same amount of line (say one foot) as the load is moving (moves one foot), then there is no mechanical advantage.

In a system with "X" mechanical advantage, the amount of line you pull will be equal to "X" times the distance the load moves. For example, with a 3:1 system, we need to haul in three feet of line to move the load one foot. And, of course, the force required to haul in that line / load will be one-third the weight of the load.

Jamestown Distributors has a good Youtube video of all this in action: https://www.youtube.com/watch?v=j76Z6kE4YVU

 

[Richard9547]

I stand corrected.

I also need to get some parts together and upgrade my outhaul this winter!
Trying to pull a 1:1 with a bag full of wind just doesn't work!

 

[shnool]

you folks make this harder than it should be...

I did this exact upgrade on my Capri 25 boom, including the clam cleats (also sold on catalinadirect)... the full aluminum ones are quite good.
http://www.catalinadirect.com/index.cfm ... -cp-22.cfm

I'll note that the picture shows a 4:1, with another moveable 2:1, by my math that's a real 8:1.

I'll also note that the system works great for tensioning under load up to and over 25 knots wind, however, it doesn't ease well. it requires pulling back on the outhaul (forward). I liked the system, and frankly I'm looking to replace the system within my boom on my S2 with something similar.

 

[Windy City]

Agree with Shnool. I installed the 8:1 rig and have just removed the turning block to reduce to 4:1 it took way too much effort to release the tension.