Dry Storage

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Johnsail
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Dry Storage

Postby Johnsail » Tue Sep 18, 2018 11:17 am

Hello All,

Although this topic has been discussed before, after reading the thread it didn't seem like much of a consensus was achieved, so I was hoping to try again.

I'm wondering how many owners follow the manufacturer's guidelines for blocking the boat when stored on the hard. As I've never seen a catamaran supported that way I'm expecting to get some funny looks from the yard manager if I ask him to do it per the instructions. I'm also wondering if four vertical jack-stands would be a suitable substitute to the framework shown in the owner's manual. We are hauling out a little early this year to get some work done before winter sets in. (New England)

Thanks,
John
Johnsail
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Johnsail
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Re: Dry Storage

Postby Johnsail » Wed Sep 19, 2018 10:27 am

Update:

I posted the same question to the PDQ owners group on Facebook, and received four replies. Three who follow the manufacturer's guidelines, one who does not. Two stated they were told (? by whom) that the weight of the boat should not be on the keels for long periods of time, that most of the weight should be on the blocking under the bridge deck.

One poster is also of the opinion that if damage were to occur when the boat wasn't supported per the guidelines, you risk running afoul of your insurance carrier.
Johnsail
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Iriemon
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Re: Dry Storage

Postby Iriemon » Wed Sep 19, 2018 1:34 pm

Not quite sure what you are asking here. The PDQ 32 owner's manual says the boat should be supported on the keels and underneath the forward and aft sections of the bridge deck. The manual shows using saw horses to support the sections supporting the bridge deck, but I don't know why you couldn't use jack stands in lieu of the saw horses, if that is what you mean.

Under no circumstances would I set jackstands on the sides of the hulls.

Johnsail
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Re: Dry Storage

Postby Johnsail » Wed Sep 19, 2018 7:11 pm

What I'm asking is how many actually support the boat that way, it seems odd especially when I've never seen any other cats supported under the bridge deck. Additionally, there are only two PDQ's here on Narragansett Bay, so I'm relatively certain that the yard has never blocked one up before. I suppose I'm really looking for some real world experience to back me up instead of a one-page diagram in the owner's manual with little explanation or rationale.
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Re: Dry Storage

Postby thinwater » Wed Sep 19, 2018 10:51 pm

John and I already talked, but I will repeat some of it here for the group.

I've had my PDQ 32 out many times, blocked under the keels and with stands under the hulls, but without support under the bridge deck. However, it was never for more than a week, and it was never subject to snow load. I always pulled in the summer and kept it in the water in the winter.

There are quite a few PDQs around here, several that I know of that have been on the hard through several winters (saw two of them today). None have been supported other than under the hulls and keels. The maximum snow load here is somewhat less than RI, but not that much, with 2 feet of heavy, wet snow being relatively common. I have never heard of a PDQ being damaged by blocking. Has anyone? This would be good to know.

And that is all I know. Since I seriously doubt the yard would charge extra for 4 more stands, Why not? The factory method, with no stands fore and aft, seems deficient and puts a lot of pressure on the bridge deck, where it does not seem particularly well braced to carry the load either. Finally, it is unfamiliar to yards and they might screw it up. They might put the blame on YOU if there was damage (you told the how to block it). So if faced with John predicament, I would do a little of both; the standard blocking, with 4 stands under the bridge deck with some framing.

Just curious. Can anyone post a pick of there boat blocked under the bridge deck? I'm sure we would all be interested. I had another boat that was damaged by snow load (Stiletto 27). The marina insurance picked up the tab without question. Blocking is fundamentally the marina's responsibility and they have insurance for that. I very seriously doubt the owner's insurance would ever come into play. Thus, I would let them bock it as they deem proper, and then ask for additional stands, perhaps using my framing.

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Re: Dry Storage

Postby Iriemon » Thu Sep 20, 2018 12:09 am

Last time I hauled the boat was blocked under the keels and with a couple boards (8x4?) placed under the bridge deck per the manual held in place with jack stands (2 each). I didn't take a pic though.

I don't read the manual as saying you should block the boat solely by the bridge deck, but by both the keels and the bridge deck. The manual says she can stand on just her keels without problem "for a few days" but longer time periods should be buttressed with the bridge deck supports. So that is the way I will do it.

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Re: Dry Storage

Postby Johnsail » Thu Sep 20, 2018 10:53 am

Thanks Drew and Iriemon, there are several photos included in the replies to my Facebook post, I will try to link some of them below.

https://www.facebook.com/photo.php?fbid ... pe=3&ifg=1

Well, I got one anyway.
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Re: Dry Storage

Postby thinwater » Mon Sep 24, 2018 4:42 pm

Slightly off topic, but perhaps of interest. Numbers always help me.

I needed to move the keel blocks on my F-24 (~ 2000 pounds) to paint the bottom. It turns out that the keel blocks on a PDQ are on the bottom of the keel, small, and not worth worrying about, but on the F-24 they are large and in important places. In order to lift the boat from the keel I tighten the screws on bow and stern jacks, which carry about 900 pounds each when fully loaded. The screws are not too hard to turn by hand (grease them!), but a short pipe makes it quite easy at that load.

Thus, while the jacks are rated for far more, the most you are likely to get on them as pre-load is ~ 1200 pounds each. Jacking under the bridge deck, with four jacks, let's say 4800 pounds. That seems reasonable to me, and I'm not sure I would want to go any higher. Some one else can suggest whether carpet for padding makes sense. Obviously you want some good timbers, 2x10 at least, although thicker is better. The safe working load of the jack stands is typically 10 tons.

The obvious flaw in the PDQ manual instructions is that there is no way practical to balance the load between the keel blocks and the deck sawhorses. It strikes me as something that works on the engineer's desk but not in the field. Jack stands are better.

The other concern is that the feet are small and will settle unless there are good pads under them (depends on the soil).

That's it. If you are jacking under the bridge deck with 4 jacks, make sure they have good blocks under the feet and pretension them hard by hand. Good luck!


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