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DSII CB Downhaul repair

PostPosted: Tue Nov 12, 2019 3:01 pm
by Nephroid
Adding my experience to what seems to be the single most discussed topic on this forum. As mentioned in my recent shakedown sail report ( the biggest issue I had was the CB downhaul line jamming between the CB and inside of the trunk.

My DSII is a '72 and the downhaul line exits the top of the CB trunk near the horn cleat. When lowering the CB, this puts a lot of rearward pressure on the downhaul which causes it to "derail" and jam every single time. Pulling harder on the line only causes it to jam more and once set. Once jammed, the CB is virtually immovable. Note the that the SS uphaul line and tang have a relatively straight run and don't seem to have any issues.

View of the jammed CB from below - uphaul is 1/4" nylon line
IMG_4500.JPG (85.96 KiB) Viewed 4097 times

Following the advice on this forum, I was able to get her off the trailer and careened in my back yard. It seemed no matter how many times I tried, the downhaul would derail every single time I pulled on it. Keeping tension on both up and downhaul lines didn't make any difference. In the end I decided to remove the CB to get a better look. Accessing the bolt through the inspection ports and removing the CB was a breeze. Getting it back in should be more fun.

Bury that rail!
IMG_4507.JPG (222.39 KiB) Viewed 4097 times

After inspecting the CB I noticed right away that the "top" of my CB that the downhaul wraps around is not level but actually tilts to the side. This appears to be a defect in the molding but definitely encourages the downhaul to pull to one side under tension.

View of the "top" of the CB - uphaul line is supposed to wrap along this edge when CB is up
IMG_4513.JPG (145.09 KiB) Viewed 4097 times

Having the downhaul routed towards the back of the trunk top seems to have been a poor design choice which encourages the line to pull "into" the CB rather than "away" from it.

Here's what I'm considering for a fix:

1. Sand or grind the top/front of the CB level so that a tensioned uphaul isn't encouraged to pull to the side
2. Grind a shallow channel into the top of CB to further encourage the uphaul to stay on the edge of the CB - consider epoxying the line into the channel. The line will still take the primary load but the epoxy will hopefully keep it tacked to the CB.
3. Add some form of mechanical support for the downhaul line - either metal clips or conduit affixed to the CB top or beads threaded onto the line to discourage it from derailing and slipping between the CB and trunk
4. Increase the line diameter from 1/4" to 5/16" - this makes it less likely to jam but if it does dam, it could be really bad.

I think regardless I'm going to grind the top of the CB flat. Has anyone had any success with the other options?

Edit: Corrected thread title. Previously mislabeled "Uphaul Repair"

Re: DSII CB Uphaul repair

PostPosted: Tue Nov 12, 2019 4:26 pm
by GreenLake
The idea of a "channel" sounds like it could work.

Easiest way to do one is to use 3M High Strength Marine Filler (it's fiberglass reinforced). You'd scuff sand the edge of the CB, then apply the filler, then cover with saran wrap or wax paper then press the CB downhaul into the filler to form the channel (and you can further shape it as desired: make the groove as wide as practical). Being reinforced, this filler is strong enough to stand proud of the repair and even form a ridge as needed. (That's unlike other fillers that primarily are intended to fill depressions before sanding).

By using the filler, there's no need to first square the CB edge.

Re: DSII CB Downhaul repair

PostPosted: Tue Nov 12, 2019 5:27 pm
by Nephroid
Thanks. I'll have to look into the 3M compound. Sounds like handy stuff to have around.

Follow-up question. In places where a repair requires sanding or grinding past the original gel coat, what should one use to cover the now-exposed epoxy?
Is it generally better to just paint over the repair (seems easier) or is it preferable to try and re-gelcoat the repair?

Re: DSII CB Downhaul repair

PostPosted: Tue Nov 12, 2019 9:56 pm
by GreenLake
You won't expose epoxy - you'll expose polyester. The filler I mentioned works fine as a sealant. It's slightly green, so nothing you might want to leave uncovered on the hull or in the cockpit, but I've not bothered hiding it under anything on my CB.

It's vinylester based, which makes it decent at sealing water, but it also means that it's compatible with gelcoat. (Be aware that gelcoat unless modified doesn't cure if exposed to air - learn how to modify or cover it correctly and then you should have no issue restoring small defects in the gelcoat).

Some people will restore even large areas of damaged/weathered gelcoat. I think this would take some practice to get right. For smaller, localized repairs I'd say, give it a try. Especially if the remainder of the gelcoat looks (or feels) good. Even after making a spot repair, you can still paint your hull, for example, if you'd like a different (or more even) color.

Matter of taste.

Re: DSII CB Downhaul repair

PostPosted: Thu Nov 14, 2019 12:00 pm
by Nephroid
In the end I decided to grind the leading edge level and carve slot into the CB. By carving directly into the CB, I wouldn't have to worry about adhering more material. I was also a little worried about clearance inside the trunk.

I started with an electric palm sander and an 80 grit sanding disk. The sander chewed through the gel coat and poly really quickly. The edge was level in only a few short passes.

CB edge sanded level (approximately)
IMG_4516.JPG (37.54 KiB) Viewed 4070 times

Under the gelcoat you can also see the filler holes for what I presume are steel stringers that run down the CB. Most importantly to me, there was not core in sight and everything still looked water tight.

Stringers visible from the top of the CB
IMG_4517.JPG (67.01 KiB) Viewed 4070 times

So far so good...

Note: The dust looked really nasty. When working w/ fiberglass please do outside and be sure to wear a mask!

Re: DSII CB Downhaul repair

PostPosted: Thu Nov 14, 2019 12:37 pm
by Nephroid
Now that the board was level, it was time to cut the groove. I used my dremel with a 3/8 sanding head attached. Then using the downhaul line as a guide, masking tape was used to mark the channel. My goal was to run the channel across most of the top of the CB from the uphaul tang down to the downhaul attachment point. This was the primary area where the downhaul was derailing.

Marking the groove to be cut
IMG_4519.JPG (79.77 KiB) Viewed 4070 times

I cut the channel free hand using the tape and my eye as a guide. The channel was about 3/32" deep which seemed sufficient for the downhaul to have a seat. Was afraid that going deeper and putting too much stress on the CB edge.

Test fitting the downhaul
IMG_4522.JPG (77.48 KiB) Viewed 4070 times

Finally I gave it a couple quick coats of white Rustoleum that I had laying around the garage. Probably not necessary but thought it looked better this way.

Quickly painted w/ white Rustoleum
IMG_4524.JPG (58.45 KiB) Viewed 4070 times

Re: DSII CB Downhaul repair

PostPosted: Thu Nov 14, 2019 2:26 pm
by GreenLake
Looking forward to your report of how this worked out.

PS: I would cover the exposed/sanded areas with air curing neutral (transparent) gel-coat past from EverCoat. It does a nice job adhering and will stand up to this use.

Re: DSII CB Downhaul repair

PostPosted: Thu Nov 14, 2019 3:37 pm
by Nephroid
Thanks, GL. Will look into that. The Rustoleum was a last minute improvisation and I'm definitely looking for something more durable.

Edit: Is this the stuff you're referring to?

Edit 2: I assume I'll have to sand off the paint first before applying the Gel Paste, correct?

Re: DSII CB Downhaul repair

PostPosted: Thu Nov 14, 2019 5:47 pm
by GreenLake
I missed that you already had put paint on there. May well be enough if the boat is dry sailed. (Stored on a trailer when not used).

Otherwise, yeah, that's the stuff.

The way you've done your groove it appears U shaped with horizontal shoulders. I might have slanted those shoulders inward a bit (shallow V) so that if the DH ever comes to rest next to the groove there would be a positive encouragement for it to slide back down into the groove as you pull on it.

If that consideration appeals to you, you would be sanding at least some of the paint anyway and that might be reason enough to use the gelcoat paste.

Re: DSII CB Downhaul repair

PostPosted: Thu Nov 14, 2019 6:22 pm
by Nephroid
A chamfered shoulder makes a lot of sense given what I’m trying to accomplish. Will give that a go.
Was overall surprised at how quick the CB was to reshape. Probably 45min total so far.

She is dry sailed so I may save the Evercoat for the numerous gelcoat repairs on my list. I also have an incentive to finish the job quickly since I left my DS still rigged sitting on the lawn. Waiting to hear from my HOA any day now... :roll:

Re: DSII CB Downhaul repair

PostPosted: Thu Nov 14, 2019 6:30 pm
by GreenLake
Sounds like you have a plan. Good luck!

And the EverCoat is great for all sorts of touch ups. (It has a slight bluish tint, so not the best for white; they have a white past as well, but it's not air-curing)

Re: DSII CB Downhaul repair

PostPosted: Sun Nov 24, 2019 11:59 am
by badgley
Hi Nephroid,

This is great work - I will be curious to hear if it improves your problem. I suspect it will. I'm sure I'll regret saying this, but I've never had the jamming problem before. I did notice that, when I had my board out for other repairs, the edge was nice and level and that it seemed to have a slight groove (intentional or just wear, I don't know). I always wondered if this was why.

Also, I recommend the thicker line. I use that in mine and it actually doesn't look like there's enough space in there for it to jam (it's also just enough stiffer that I think it tends to stay in place a little better). I think the 'official' spec is for the thicker line, and Rudy recommended it at DR when I replaced my downhaul.

Re: DSII CB Downhaul repair

PostPosted: Mon May 04, 2020 11:09 am
by SteveR
So it sounds like it is impossible to replace the downhaul line without completely taking the centerboard out of the boat?

Re: DSII CB Downhaul repair

PostPosted: Mon May 04, 2020 6:15 pm
by GreenLake
SteveR wrote:So it sounds like it is impossible to replace the downhaul line without completely taking the centerboard out of the boat?

It would certainly seem so.

Re: DSII CB Downhaul repair

PostPosted: Tue May 05, 2020 7:23 am
by badgley
SteveR wrote:So it sounds like it is impossible to replace the downhaul line without completely taking the centerboard out of the boat?

You definitely need to unbolt it, but it doesn't necessarily need to come all the way out. I think, in most setups, if you can just drop the front of the board several inches you could get to the knot. Then you could thread a new line from above, fish it out and secure it, and then reinstall the CB. It depends on your trailer arrangement. You may even be able to scoot the boat on the trailer to make this happen. Unfortunately for me crossbars and axle were always somehow in the way, but I'm pretty sure I've seen posts on here where this worked for others.