How is the mainsheet block attached to CB trunk?

[diffusion]

Did a forum search and didn't find a specific answer, so...

As part of my rehab of #10721, my attention is now focused upon the mainsheet swivel block, which appears to be the original equipment mid-boom sheeting hardware. I'd like to replace it with a better stand-up racheting block & swivel cam cleat, which means removing the original piece in its entirety. I'm just curious though - how is this fastened into the CB trunk top? I can see the tops of the four screws - are they simply self-tapped into fiberglass (hard to believe that is strong enough given the tension loads)? Or is there a more elaborate answer, like machine screws tapped into an aluminum plate glassed into the trunk top?

If my replacement swivel block base has a different bolt pattern, what would be the recommended way to fasten it with sufficient strength?

Same question applies to the future cam cleats that I would like to attach to the CB trunk top to facilitate improved jib sheet handling - what to fasten with? Speaking of which, I'm considering cam cleats on swivel bases rather than fixed. Anyone done that?

Thanks all!

[rnlivingston]

On both my Daysailers, there is a metal plate that is glassed in. There are four tapped holes the screws go into. When I replaced the swivel on the 1966 Daysailer, the holes did not line up, but there was enough room to drill and tap new holes.
Hope this helps.

[K.C. Walker]

It's not the best picture but here is my solution. The standup ratchet block on a swivel cam cleat is mounted on an ad on wood platform. I've been using it for three or four seasons and absolutely no problems. I thought about trying to re-drill the holes in the original location but I actually needed more platform.



I totally agree with your decision to go this direction, it is much better than the original set up.

[TIM WEBB]

On both my Daysailers, there is a metal plate that is glassed in. There are four tapped holes the screws go into. When I replaced the swivel on the 1966 Daysailer, the holes did not line up, but there was enough room to drill and tap new holes.
Hope this helps.

+1, same here, although at first I made an adapter (pic in my gallery), until it occurred to me that I could drill/tap new holes at 45 degrees from the originals ... ;-P

[klb67]

I had no mainsheet blocks on my 76 DSII when I got it. I installed a harken ball and socket stand up base and 57mm swivel ratchet block and cam cleat to handle the main sheet. 4 stainless bolts threaded into the existing holes in the trunk - I believe they were the original holes. They aligned well with the stand up base. There is a plate imbedded under the glass. I like my mid boom sheeting set up (my wife at the helm on her first sail in the DS)

[diffusion]

Klb - perfect! It's good to know there is a harken swivel block base that matches the bolt pattern - I'm going to hunt that down.

Thanks for the info everyone.

[TIM WEBB]

I replaced the original with the Garhauer from D&R, which has a bigger "footprint".

However, klb your pic illustrates something that has been debated here before: the advantages/disadvantages of having a mainsheet cleat that releases down vs. up (Garhauer and Harken are both "down"). As the pic shows, with a downward release, at pretty much any angle except sheeted in as tight as possible, a pull on the sheet from the seat or rail results in a *release* of the sheet, not cleating of same ... ;-P

KC, your pic illustrates an arrangement where the cleat is on a swivel *below* the spring-loaded "stand-up" portion of the block, and is therefore at the same angle no matter what the angle/position of the boom, so now I can see where you would then prefer the upward release.

[GreenLake]

My original Big Whale tufnol stand-up block and cleat for the main (on a DS1) has an upward release (pulling up releases).

My take: it's nearly always possible to pull more upward, so you can never get stuck with the sheet cleated. The angle of the fitting is such that positive cleating is possible from all seating positions (in other words, a pull that clears the rail plus knees of the operator is low enough to affect cleating).

I've sailed on a DSII with original downward release and had the main cleat itself constantly when going upwind in gusty winds, where I was very interested in not having the d****n thing cleat itself. I really, really hated that .

If you fit a ratchet block, there's even less need for the main to be cleated all the time, so the utility of "auto cleating" is even more marginal -- but to each his own.

[klb67]

Tim: Good observation. I was then, and am still, learning to sail the DS and decided against cleating the main in most circumstances for now, so I had it adjusted out of the way, more or less. I THINK that I can switch the cam cleat to mount to cleat down, release up, if I reverse it. I can't recall for sure without it being in front of me. I could be wrong.

Diffusion: Note that the base I got is described as a low load base or something like that. It's what my local sail shop handed me (along with the other blocks) when I explained what I needed, and the owner made some recommendations and showed me how to install it (we had to try a few different bolt threads until we picked the right size). Anyway - they make one with a stainless plate on top, which is stronger. I don't know if that's needed for a DS or not - just wanted to point that out. I've had no issues with mine, but I'm on an inland lake with no sustained strong winds for long periods of time (if there are, at this point, I'm sailing my sunfish or not at all). There are also less expensive but likely equally as good systems - for my mainsheet I didn't really shop around. I took the boat to my local shop to go over it with me and make a list of - this is good, replace this now, consider replacing this down the road. He spent at least a half hour going over my boat and made some great suggestions. I was happy to pay that back in getting new hardware from him rather than saving a few bucks at the time. Good luck getting your boat set up.

[diffusion]

KLB, I further noticed that you have your mainsheet tackle configured for a 4:1 purchase - how do you like this? Before I order my parts, I'm trying to decide on 3:1 vs 4:1. I'm sure my wife would like the extra power of the 4:1, but is it worth the extra line you have to take up?

[klb67]

Diffusion - I'm probably not qualified to advise on the 4:1 purchase - this DS is my first "big" boat and I haven't had enough time on the water in it or other boats to really know. I haven't noticed it being a problem to pull that much line, mostly because I don't often run dead down wind and have to get the sail all the way in before tacking. I will say it is comfortable to sail with this rig. I sailed solo in pretty strong wind for my area, to the point I could have used another person, and it was fine to hold.

Maybe others with more experience can comment on the desired purchase ratio for a mid-boom sheeting.

[diffusion]

The mainsheet tackle on my previous 28' keelboat was a 4:1 purchase, and with a mainsail 3X the area of the DS, it wasn't all that bad, but I had end-boom sheeting on that boat.

I'd imagine 4:1 on the DS provides a very light effort. I've only had my DS out on the water once so far, and the stock 3:1 mainsheet was ok, but I didn't love it. Right now I'm thinking I'll go 4:1. as you did.

[K.C. Walker]

I like 4:1 for a cruising set up. My boat came with mid-boom 3:1 and I did not love it, either. Sure, there's a bit more line under foot when close hauled with a 4:1 set up, but it's not that bad. I'm actually using a rear deck bridle but the ratio works out the same as 4:1 mid-boom. The class champion, Mike Gillum, uses what would work out to be 3:1 as a mid-boom set up and swears by his set up which is a Snipe style split tail main sheet. He uses two ratchet blocks, though.

I think with 4:1 you could get by a lot of the time without gloves for trimming the main. With 3:1 you would want gloves much more often.

[tmittner]

I have 4:1 mid boom sheeting on my DSII. I see Harken has a double hexarachet block on clearance (2.25"). If I put that on my boom, would that be overkill? Intended use is recreational cruise sailing in as many wind conditions as possible.
Tom

[K.C. Walker]

I'm not familiar with that block. I looked at the Harken site to see if both ratchets engage or whether they can be independent. I suspect that they both engaged with the same switch. In that case, yes, I think it is overkill. With a 4:1 it is very rare that you would want two ratchets engaged. I have the next size up at 75 mm on my centerboard trunk. I also have a 40 mm ratchet block on my boom that I almost never engage.