Even in your drawing where you illustrate the 1:1, if the line is pulling at a 45 to the line of action of the boom than the true purchase is cut in half. I see where Kloudie is coming from. I also see what you are saying.
Finally REALLY sailed my boat
- Thread starter Hermit Scott
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Ok just to be sure I am seeing this right, I see 2 line parts on the aftmost block, and 2 on the other two blocks, meaning 6 parts of line connecting the boom to the cabin top.. the tension in the line is the same everywhere, so if that block at the bottom of the mast were aft with the others, it would be a 6:1 advantage.. because it is not Ed Zachery in the same place, some of the tension force goes to compressing the boom.. but most folks would call it a 6:1..
Scott's setup is not like the Catalina 30 rigging diagram... he is missing the extra block in the middle of the gang. So... Sailingdog is correct... it is only 5:1.
In addition he has omitted the block at the gooseneck, leading the forward line directly to the mast base.... essentially turning the system into a vang and putting extra strain on the forward bail. If the line ran parallel to the boom, as designed, the strain would be carried by the two blocks on the mast instead of the forward bail. He really should change this and add a block to the gooseneck, then install a dedicated vang system.
Sorry, I can't get the picture from the manual posted... maybe someone can help if there is any interest left in this thread. http://www.catalina30.com/TechLib/PartsManual/Rigging.pdf see page 8.
Ok, consider a block with a rope thru it. If the line has, say, 10 # of tension on it then the block will pull with 20 # of force.. The tension in the line is the same everywhere in the line.. Now add another block that has two line parts thru it with 10# in the line.. Now ya have 2 blocks pulling 20 each or 40# pull.. Add a third block the same way and now ya have 60# pull on the piece that you've connected them together with .. and with 10 # of tension in the line .. 6:1 .. NOW.. if ya take that last block only and move only one of the directions from which the tension is pulling, opening up the angle so that the ropes aren't pulling in line with the block anchor, (as Scott has done) that last block will not pull with its full 20#.. but it will be more than 10 which you'd get if you terminated the line at that block .. so ya really do technically have more than 5:1.. You could change it to 5:1 by putting a block on the goseneck before leading it down to the deck..
I disagree. Inserting another block at the gooseneck will not change anything, purchase wise. What it will change is the allocation of effort, balancing it between the two mast blocks,(90+90 degrees). As it is now the front bail's block handles about 30 deg, while the mast base handles around 150. If the gooseneck block is added, the forward mast block reverts to only being part of purchase effort #4. Its strain will be significantly reduced and more in line with the direction of the bail, i.e. pointing in the direction of the traveller.
Again, I ask you to examine the Catalina drawing.... it will be made crystal clear. http://www.catalina30.com/TechLib/PartsManual/Rigging.pdf Page 8
I just saw that I am missing a block above the traveller. If I rerig it, I am going to do it with a triple block like saildog's diagram, so the vang system will be clear. Unless I do build the elevated traveller, then I will have to think of something else probably like it is supposed to be in the diagram. I want to elevate the traveller so I can have a more permanent cover over the companion way.
I like drastic changes to make it more like I like it. I think I am going to cut the hull down the middle and widen it out a foot or so, get a little more elbow room in the cabin.
Maine-The day I am supposed to move it to Port Aransas(1st), the weather forcast says "windy". It should make for an interesting day. Windy in Corpus can be pretty intense.
I like drastic changes to make it more like I like it. I think I am going to cut the hull down the middle and widen it out a foot or so, get a little more elbow room in the cabin.
Maine-The day I am supposed to move it to Port Aransas(1st), the weather forcast says "windy". It should make for an interesting day. Windy in Corpus can be pretty intense.
HS—
If you want to elevate the traveler, you'll probably want to get a heavier track, so that it can bridge the opening without having to be through-bolted there. The Garhauer Unibody travelers might work well for that.
If you want to elevate the traveler, you'll probably want to get a heavier track, so that it can bridge the opening without having to be through-bolted there. The Garhauer Unibody travelers might work well for that.
Even if you go by the catalina diagram, that bail is facing the wrong way. If you notice in the drawing it is hanging unnaturally. That was in the days of hand drafting, mistakes that were small often stayed put.
looks like the bail is wrong to me also. have you thought about an arch over the cockpit for the main sheet? its also a good place for radar and vhf antenna with under mount for vhf and instruments.
handles totally different with both sails don't it?
have fun on the move.
if its southerly wind it will be great!
handles totally different with both sails don't it?
have fun on the move.
if its southerly wind it will be great!
I agree Scott, the force vector on the right hand block would push the blockto the right since the vector will be normal to the line at the midpoint of the angle formed by the line. I have the same set up on my boom but i think the line arrangement is preferable compared to running the mainsheet up to the mast. Instead it drops down to a turning block through bolted to the deck. You could put on in line with the right angle for that bail, then it leads perpendicular to the centerline of the boat to the starboard side to another turning block that is mounted on a wood block bolted to the deck and from there to the cockpit. It avoids the vang and unclutters your mast. I'll try to take a picture next time I'm on the boat, but look around your marina and see examples of other boats to get ideas.
Thanks SD... for the pic...now regarding this discussion:
Either re-set the bail, or replace it with a thru bolt type that will move. A new bail isn't that exensive and it won't interfere with the internal outhaul. Garhaurer sells them $5 to $17.
The real issue is Scott's omission of the extra block above the mainsheet fiddle block which will make the purchase 6:1.... and the omission of the gooseneck block which keeps the mainsheet out of the way of the vang, if he had one. And NO... the mainsheet tackle can not effectively act as a vang the way he has it rigged because it will not hold the boom down when the sheet is eased out all the way.
If was me, I'd just get this $75 Garhaurer triple block with becket
and run the line like SD's drawing, only lead the mainsheet forward at deck level to the mast base turning block, then back to the cockpit. Then I'd start saving for a rigid vang.
Either re-set the bail, or replace it with a thru bolt type that will move. A new bail isn't that exensive and it won't interfere with the internal outhaul. Garhaurer sells them $5 to $17.
The real issue is Scott's omission of the extra block above the mainsheet fiddle block which will make the purchase 6:1.... and the omission of the gooseneck block which keeps the mainsheet out of the way of the vang, if he had one. And NO... the mainsheet tackle can not effectively act as a vang the way he has it rigged because it will not hold the boom down when the sheet is eased out all the way.
If was me, I'd just get this $75 Garhaurer triple block with becket
That's why I was suggesting the triple block with becket for the mainsheet traveler car, so that the lines would pull in alignment with the bails, reduce the risk of damaging the boom, and keep clear of the boom vang. 
Yard
I just went through my pictures from the past years and the PO or yard ran my rigging in the first photo. I never changed it because it used all the hardware that came with the boat. Picture 2 show our friends MKII as the yard or PO left it. Both show a 5:1. Picture 3 kinda shows the vang in twist mode, but not well. I don't have a shot showing that near the boom. Picture 4 shows what happens when you get tired looking at your own boat.
To make the bails work, the line should run vertically between the traveler and mid bail, then to the forward bail, then the aft bail. The last pass is going forward from the traveler. IMHO :neutral:
All U Get
Hi again,That's why I was suggesting the triple block with becket for the mainsheet traveler car, so that the lines would pull in alignment with the bails, reduce the risk of damaging the boom, and keep clear of the boom vang.
I just went through my pictures from the past years and the PO or yard ran my rigging in the first photo. I never changed it because it used all the hardware that came with the boat. Picture 2 show our friends MKII as the yard or PO left it. Both show a 5:1. Picture 3 kinda shows the vang in twist mode, but not well. I don't have a shot showing that near the boom. Picture 4 shows what happens when you get tired looking at your own boat.
To make the bails work, the line should run vertically between the traveler and mid bail, then to the forward bail, then the aft bail. The last pass is going forward from the traveler. IMHO :neutral:
All U Get
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towman-I was intending to put an arch across the back, that would get used for the dinghy, and maybe hooking a bimini to it. If I put the arch forward enough to put the traveller on it, then I can't use it for the dinghy and would be effectively useless. If I put an arch in the front, I get to make a dodger(actually removable hard windows) to cover the companionway. I think that would add the most comfort. I kinda like hauling the inflatable up onto the deck with a halyard and keeping it there.
Also I can say with certainty that a rigid vang is in Event Horizon's future.
Joe-that is a good choice for a triple block for this problem.
Also I can say with certainty that a rigid vang is in Event Horizon's future.
Joe-that is a good choice for a triple block for this problem.
Be careful when making a hard dodger, as some will add a lot of windage to the boat and change how she handles significantly.
I thought the main sheet HAD to go from somewhere on the boom to the mast or goose neck to allow it to go along the traveller without releasing the mainsheet tension? Did you do that yourself or is the factory?
I really like how your dorode (sp) boxes are. I am going to build a mold and make some out of fiberglass and glass them to the deck near the sides of the mast like yours are. I just need to know how the guts of the box is set up and some rough dimensions. I think I can go ahead and build them and glass them in and cut all the holes before I buy the cowls, because the rain will leave out of the weep hole on the side even with out the cowl in place.
BTW jibes I think your boat is perfect. I really like the way Odays look and are set up. I almost had an Oday30, but the guy wasn't ready to take my creative financing. The day after I bought my C30 he called and said he would take my deal. It was shoal draft and had a 15 or 18 hp yanmar. I would have been much happier in that boat.
Factory set up
Scott,
Thanks for the compliments. The O'Day's give you a lot of boat for the money. They were pretty much a heads up competitor with Catalina, we know who survived. Their smaller boats were their mainstay but they were enticed into larger boats I assume for higher margins. Didn't last long. They built many tens of thousands of boats before going belly up. The company changed hands several time before the final collapse. At once point the same company that owned Smith and Wesson owned O'Day. You can get a 34 ( same as the 35 without the swim platform stern) in the $20's.
The mainsheet is factory set up. I really don't understand your first comment about mainsheet having to run up to the mast. Many mainsheets are attached at the end of the boom and go directly to the cockpit, some boats have travellers right in the cockpit. I'm somewhat surprised at your set up as I can't say I've ever seen the mainsheet lead like that up to the mast. Take a look at other boats for ideas. My pictures may help if you look closely directly below the front mainsheet block on the boom is a stand up block bolted through the deck. This can tilt and pivot so it self aligns to the loads on the line. It then runs to a sheave mounted flat on a wood block that is bolted to the deck (through bolted, high loads on this sheave) that turns the line 90 degrees and runs it back under the dodger to the winch mounted right next to the companionway.
Regarding the dorade boxes, there is a plastic pipe mounted in a hole through the deck that sticks up into the dorade box well above deck level. The hole in the box for the vent scoops is mounted offset from that pipe so water goes in and doesn't go into the boat and drains out small holes in the bottom. In a real storm there are caps to replace the scoops to keep the water out. Air goes in the scoops and pressurizes the box and thus goes down the hole into the boat. I since stuck a solar vent in one of them to keep air moving if the scoops aren't aligned with the wind or on those hot days with no wind at all. works well but the vent overhangs the box a little so it looks ugly. It is just sitting in the hole so I can pull it out and stick the scoop back in any time. To keep mold and mildew out of your boat this is the best project you can do. I highly recommend this as I had a boat without it once and the difference is amazing. I also have a forward hatch that I can leave open a crack and it doesn't let water in when it rains so i get a little ventilation from that too.
Scott,
Thanks for the compliments. The O'Day's give you a lot of boat for the money. They were pretty much a heads up competitor with Catalina, we know who survived. Their smaller boats were their mainstay but they were enticed into larger boats I assume for higher margins. Didn't last long. They built many tens of thousands of boats before going belly up. The company changed hands several time before the final collapse. At once point the same company that owned Smith and Wesson owned O'Day. You can get a 34 ( same as the 35 without the swim platform stern) in the $20's.
The mainsheet is factory set up. I really don't understand your first comment about mainsheet having to run up to the mast. Many mainsheets are attached at the end of the boom and go directly to the cockpit, some boats have travellers right in the cockpit. I'm somewhat surprised at your set up as I can't say I've ever seen the mainsheet lead like that up to the mast. Take a look at other boats for ideas. My pictures may help if you look closely directly below the front mainsheet block on the boom is a stand up block bolted through the deck. This can tilt and pivot so it self aligns to the loads on the line. It then runs to a sheave mounted flat on a wood block that is bolted to the deck (through bolted, high loads on this sheave) that turns the line 90 degrees and runs it back under the dodger to the winch mounted right next to the companionway.
Regarding the dorade boxes, there is a plastic pipe mounted in a hole through the deck that sticks up into the dorade box well above deck level. The hole in the box for the vent scoops is mounted offset from that pipe so water goes in and doesn't go into the boat and drains out small holes in the bottom. In a real storm there are caps to replace the scoops to keep the water out. Air goes in the scoops and pressurizes the box and thus goes down the hole into the boat. I since stuck a solar vent in one of them to keep air moving if the scoops aren't aligned with the wind or on those hot days with no wind at all. works well but the vent overhangs the box a little so it looks ugly. It is just sitting in the hole so I can pull it out and stick the scoop back in any time. To keep mold and mildew out of your boat this is the best project you can do. I highly recommend this as I had a boat without it once and the difference is amazing. I also have a forward hatch that I can leave open a crack and it doesn't let water in when it rains so i get a little ventilation from that too.
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