Hi all,
My boat is coming out of the water next Saturday, and I need to buy some 6"x6" Pressure treated blocking for under the keel. Does anyone know the length of the wing keel. I thought I would put a couple of 6x6's fore and aft and then a few pieces on top of them at 90 degrees for the keel to rest on. Not sure how long the pieces should be. I should have measured before it went in the water in the spring. I'll be using six side stands (3 per side) and a bow "V" stand. Thanks for any input you may have.
Mike.....
Mike : There have been a number of Mainsheet articles written on blocking a wing keel.
You need the weight of the boat on the nose of the wing NOT on the aft of the wing!! I seldome have any blocking under the aft portion of the wing.
If you don't keep the 75% of the boat weight on the nose of the wing, it is guaranted to have a Catalina Smile!! :cry4`
Hey Mike, my '88 Wing Keel is 71" measured down the centre.
I've been struggling with my cradle since the day I got it; every year it fits a little better. The way we haul-out at our Club (putting the boat on the cradle and then moving them together) makes it difficult for me to get that 75 / 25 distribution but I'm working toward it.
The other thing I'm working toward is getting the right bow-up attitude for decent cockpit drainage. Even though the stupid thing doesn't drain in the summer, might as well try to get it to drain in the winter.
Thanks Ron and Steve. It sounds like I should keep the blocking biased to the forward part of the keel, maybe the forward 1/3rd? As always, I appreciate everyone's input. This is my year of "firsts" for all of this.
Mike.....
Don't know it this will help but here's what I found to be where the centre of mass exerts its force on the keel of my boat. This is with no weight on the pads. You can see under the keel forward and aft of this point.
[attachimg=#]
Ron, don't cringe too much, this was the second year on my cradle, last year I moved it forward I think 18" which didn't help as much as I'd have thought. This year I'm revamping my wedge to incorporate the curvature of the keel (to avoid bending the longitudinal beam of the cradle thereby reducing the twisting of the cross-members) and trying to get the weight on the front.
Mike : Steve is in a shipping craddle. Follow my advice if you use jackstands!!
Block the first 1/3 but make sure the travel lift operater know that you want the majority of the weight on the NOSE of the wing.
The engine and a full fuel tank are all aft the CG. The lead wing just sits there and the worst thing that will happen is that the heavier stern will rotate down causing the "Catalina Smile". 75% weight on the wing and 25% of the weight on the pads!! A few thoughts
All good information and advice. Steve has the center of mass (balance point) marked right. I think that the important part is the pressure on the pads, jack stands or cradle. The keel is big and solid, it's not flexing. The only pressure or lifting at the keel joint will be put on by the pads, especially at the bow V-stand. One of the main problems up north where the ground freezing can change the pressure on the pads a lot. Not so much of a problem when storing on a concrete pad, some on asphalt, more so on ground. Jack stands need to be checked and adjusted, both at freeze and at thawing, often. What I do... I use very little pressure on the V-stand, then after the boat is winterized and cover is on, I back it off 6", way off the hull. I keep the jack stand pair forward of the keel just snug. That way I'm sure not to get lift at the front of the keel joint. When I'm working at the bow of the boat I'll bring up the V-stand to touching for the day.
If you winter at a boat yard they should be checking, ask the manager. If you are like me and at a yacht club where you are responsible for your boat, visit during the winter. Or get a buddy to do it.
Jim
Thanks everyone for all of the great information. I really appreciate it. This really helps a lot!!
Mike......
What's a Catalina smile? and i don't find a tech note about the blocking a wing keel. I have a berr with a 6 adjustable pads but i don't understand why you said 75% of the weight on the front of the keel. Excuse my English i'am learning
Andre--Here is the Catalina smile (in my case, a half smile), due to improper blocking from a marina. The pic is after I found the crack and ground down with a Dremel tool to fiberglass the repair.
Roger's is an "ODD" "smile." Usually the "smile" is horizontal, at the line between at the top of the keel.
For general information we should say that what we are calling a "Catalina Smile" is not limited to Catalina's. My observations are that Catalina's have a better than most hull to keel joint and with proper boatyard care the joint won't be a problem.
JIm
Thank you for the smile, where can i find some information about the best way for blocking with photo.
I'm a little confused by Steve's photo showing the center of force. It appears to be more toward the rear of the keel. Is that because the stern is lower than it should be? It sounds like the blocking should be aligned with the forward third of the keel, not the rear. Am I missing something? If I am blocking from the ground, should I place the blocking only under the forward third of the keel, or raise the stern enough so that there is space below the rear portion of the keel? I plan on using 6 stands on the sides and a V-stand on the bow. I would appreciate some further clarification. Some pictures would help. Thanks.
Mike.....
Roger's "Smile" does not look like a seperation in the ballast to hull joint, it looks more like a very serious crack in the keel of the boat, like it's about to break the boat in half. I'd be very concerned about a crack of that nature.
Has that boat struck bottom hard???
Ralph
Ciao Bella
I agree with Ralph, that looks like some kind of structural crack in the hull that will needs a professional opinion rather than a Catalina Smile which should be horizontal along the hull to keel joint. I too would be concerned about this crack.
Ralph and Les...yes, had it professionally checked...and the crack did not pentrate to the interior (looks worse in the pic than it was). Had it structurally checked...all ok. No hard, or any, grounding. When I boat the boat, I stripped all the bottom paint off and repainted...there was no crack. Hauled out, sat over winter, prepped bottom for the season in Apr, and found the crack (it was more hairline...but I dremeled it out to get enough material in). Now, one could argue the yard may have dropped the boat, or damaged it in the sling...but I had no evidence they did something wrong...could not prove they caused the crack. Anyway, repaired it and went on my merry way...that was something like 6yrs ago and everything is still fine (know this, cause I again removed all bottom paint about 2yrs ago and no hull issues).
Then your good to go....great!
Roger : You have a structural fracture just aft of the wing. I believe that yours might be exarbacated by keeping tooo much weight on the aft pads/jackstands.
I'd have someone of knowledge inspect your hull (especially from the inside). I'd also sent a series of pictures off to Gerry Douglas at Catalina for his openion!! Good Luck! A few thoughts
Roger, Is that the prop strut in the lower right corner?
Ted, it is the prop strut...crack was just forward of it.
Ron, I had it checked on the interior prior to repair. I brought 2 different companies in to look at it...before I dremeled it and after. The advice I was given, open it up in order to put repair material into it...so keep in mind, it was mostly a hairline crack that I opened up...but there were a couple of areas the crack was a litle wider (but not much more than hairline)...so I opened that area up more.
Others who have inquired: I did the prep work, had the professionals do the actual repair. I have had no issues since...this all was around 2004, so 8 yrs later and all is good. The only thing I did after the "professionals", was to do some light sanding to smooth down a small hump around the repair...figured I could get another .0001 knts out of her.
Ron--To address your other comment, I had requested the yard start blocking the boat level or bow down, and add a stand behind the prop strut...they were not doing that before. So, I think you are probably right, improper blocking caused the problem. Then I changed marinas...8 yrs later, no problems...and I keep blocking either level or bow slightly down. If you think the bow down is not good, let me know. Thanks for the input.
This is how I have the marina blocking now...since the crack. Ron, Stu, if ya think I got it wrong, let me know. I have one stand on the bow, 2 each along port and starboard, and one behind the strut.[attachimg=#][attach=#]
Roger : What I'd recommend is that you block with 3 stands on each sides on either side and forget the stand on the bow (That's for a fin keel boat). It appears that when they put the stand on the rear of the strut there was way tooo much weight put on it!!
As long as there is no break on the inside of the hull you should be OK with a fix in the outside. I'd gouge it out and use fiberglass / mat and glass to fill it in. Then be very carefull on how they block the boat in the future .
Thanks Ron. That is what they did...glassed it in. Will move to three stands on port and starboard...you mentioned loosing the bow support (because I have a wing keel), what about the stern support (which may have caused the problem)? Just go with three stands each on port and starboard? Thanks again.
Mike, my point is that wherever you block, the centre of mass will act at the location I indicated. The further forward you go means more weight that needs to be supported by the aft pads.
Obviously there is a blocking point on the keel that results in the 75:25 ratio, and my guess is that Ron's got it figured out, so if that's what you want to achieve, he'd know, so might be best to go for the 1/3 from the front as I think he mentioned.
As an aside... I value the opinion of Ron, and what Catalina told him about the 75:25 thing... but.... when I bought my boat the PO was still using the original Catalina shipping cradle. Both that one and the adjustable cradle I had made later have the rear pads at a location on my boat that has neither a bulkhead or even stringers on the other side of the hull. Consequently, at those points, I have minor surface cracks in the finish of my hull because of flexing. Personally I will endeavour to move some weight aft, but I'm not aiming for quite 25%.
Steve
Just to clarify. Ron said put 75% of the weight on the wing (ie the keel) and only 25% on the pads. In other words, if your pads are causing the hull to flex, they are too tight and need to be backed off. You will find that the flexing causes doors to jam inside: a clue that something is not right..
Others have talked of "bow-down" storage. You want to be sure that any water still runs off the stern so be careful with that. The boat will naturally settle on the keel a bit stern down, so lifting the stern seems risky to me: maybe even cause the kind of cracking seen in that scary photo.
We use a winter storage cradle (not a shipping cradle). When lowering the boat into the cradle, we let it settle on the keel before snugging up the pads. This avoids overstressing the hull at the pad support locations. We block under the cradle to make it level and to keep the rudder off the ground. We use double or triple the amount of blocks under the keel, since that is where 75% of the weight is.
Tony
Mike and Guys : Something VERY important. When using jack stands make sure the yard crew "thumps" the hull to find the bulkheads, as that is where the jackstand pads should go.
Tony,
Thanks for the clarification.
Mike....
Roger,
If your prop strut is in the lower right corner of the picture you posted, then I think you are correct that the vertical crack was not structural. It was simply at the edge of the "filler" that is put around the prop strut during construction. I've attached a photo of the prop strut without the filler, taken during a Woodland Hills factory tour in 2006. Gerry Douglas gave the tour and explained how the prop strut is installed. This photo is actually of a C34, as the last C36, #2305, was finished and sitting outside. Hope this helps.
Tom--Thanks, your pic seems to follow the crack I had. Since I have not had an issue all these years later, that was probably it. Now, on to the other things I need to do...delayed due to a broken wrist this year. Healing just in time to put the boat up for the season...jeez....