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Optimum stand placement for C250WK

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TakeFive
Master Marine Consultant

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Initially Posted - 11/05/2011 : 22:32:00

I thought it would be interesting to discuss the optimum placement of stands for offseason storage of the C250WK. I'm putting this message into the General section because it may be of interest to C25 owners also, even though the specifics may be unique to the C250WK model.

Here's a pic of my boat in early 2010, before I purchased her:

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</center>

Here is a diagram of the placement of the boat stands in this pic. Note that stands #3 and 4 are placed just in front of the keel. I surveyed stand placement for number of other C250s at Winters Sailing Center, (huge Catalina dealer in NJ), and they were all placed similarly:

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One year ago when we moved the boat to land after our first season of ownership, we initially had the stands placed in that manner. But while leveling the boat, I noticed that once she sets on her keel, the entire remaining weight is borne by stands #1 and 2. In other words, in the absence of wind and/or weight shifts caused by someone walking toward the bow, the boat would stand entirely on a tripod formed by the keel and stands #1 and 2, without stands 3, 4, or 5. As a result, the sole purpose of stands 3, 4, and 5 is to provide additional secondary support to avoid the effects of wind and load shifts.

In light of this, I became very concerned about having stands 3, 4, and 5 all in front of the keel. With the boat's center of mass located behind the keel, I believe that stands 3 and 4 would offer stronger support behind the keel, closer to that center of mass. Therefore, I moved stands 3 and 4 behind the keel as shown here:

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</center>

Note that this offers several benefits. The key benefit is that these stands now are placed at a position where a sideways force on the boat would push most directly against them. Note also that the boat's beam is broader at this placement, providing the best moment arm to resist falling. And also, note that in this case, stands 1, 2, 3, and 4 are all along interior bulkheads, thus minimizing the flexing of the fiberglass.

I did this last winter with a successful result, and just did this again today. My greatest reluctance was that it differs from Winters' placement, and since they're a big dealer they must know what they are doing. But I still cannot see any reason to place the stands the way they do.

What do you guys think?

DISCLAIMER: If you like my idea and decide to set up your stands similar to mine, you DO SO AT YOUR OWN RISK. I accept responsibility for my own boat, but I will not accept responsibility for yours.

And, just as a reminder, the goal here is to avoid ending up like this guy in another boat yard up the road from me:

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Rick S., Swarthmore, PA
PO of Take Five, 1998 Catalina 250WK #348 (relocated to Baltimore's Inner Harbor)
New owner of 2001 Catalina 34MkII #1535 Breakin' Away (at Rock Hall Landing Marina)

Edited by - on

Chris Z
Captain

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Response Posted - 11/05/2011 : 22:41:58

My understanding is that the exact placement isn't that important. That said i think I would be placing them a third of the way from the bow or stearn. Also, a lot of people put them too far underneath because they are thinking they are supporting the weight instead of letting the weight lay on the keel.

This pic of the fallen over one is interesting. My brother's marina has banned the blue tarps because the boats end up blown over instead of falling over when the tarp gets loose and catches some wind. Also, they make the owners with stands place their boat in a different area than the cradles.

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

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Response Posted - 11/05/2011 : 23:28:01

Rick,
I've never had SL up on stands, so take this with a grain of salt.

When I was soda blasting the hull last year, getting beneath the pads on the trailer for the waist (directly in front of the keel), and forward pads was pretty easy. However, the aft pads were downright scary, so much so that I opted to not bother trying to get underneath them due to the scary crackling sounds coming from the fiberglass, even with multiple pads supporting the weight.

I'd be concerned about only having 5 places to support the boat. Are the pads on top of the stands larger than the ones on the trailer? More surface area would be good.

Edited by - on

Dave5041
Former Mainsheet Editor

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Response Posted - 11/06/2011 : 07:07:17

I don't use stands, but it would seem that checking with Catalina to see if it makes much difference would be a good choice.

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TakeFive
Master Marine Consultant

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Response Posted - 11/06/2011 : 17:33:12

Thanks for the feedback. A couple of comments.

It is true that the vast majority of the weight is supported by the keel. However, the rear stands (#1 and 2) do support a significant amount of weight, since they form the load-bearing tripod. Thus it is very important to place them properly, and make sure their orientation is such that the bulk of the hull's force against them is parallel to the screw. Stands 3 and 4 do not bear a load (they can even be removed in calm weather to access the hull for cleaning or painting), so they can be placed more broadly to better prevent the boat from tipping over.

It is because of this load that delliotg heard the crackling noise. Nothing is perfectly rigid - everything will flex somewhat. And fiberglass makes ugly sounding noises when it flexes, and can be badly damaged if it flexes too much. This flexing can be minimized by placing stands 1 and 2 right at the rear wall of the aft berth, which should be screwed in securely to enhance the rigidity of the hull form. The other way to minimize the flexing is to distribute the load over the largest possible area. My boat stands came with wood pads that are 1'x1'. However, if used as supplied with a curved hull like the C250, the load is actually concentrated over the small point of contact. Last year I used indoor-outdoor carpet to give a little more cushion. This year I used thin rubber pads.

Edited by - on

TakeFive
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Response Posted - 11/06/2011 : 18:02:34

A couple of other things.

Although I did not mention it, chaining the opposing stands together is essential. Doing so makes them act much more like a cradle would. Plywood under the legs is also important to prevent settling into the ground and rust from ground moisture.

Five stands, properly placed, is perfectly adequate for a 25 foot boat. I've never seen a yard use more for a boat this size. I had to buy my own stands (boat club rules), so I researched this carefully to ensure I was neither skimping or wasting money.

The boat that fell over appeared to be due to a several errors. There were insufficient stands - only 4 for a 28-30' boat, with nothing on the bow. They appeared to be over-extended (too small, and compensated by cranking the stands up too high). The keel was resting on a stack of cinderblocks - you can see that the stack fell in the opposite direction from the mast, so there was clearly a pivot around the stands. And the boat was stored perpendicular to the prevailing wind off the river. This is supposedly a "professional" yard that provides the stands and the manpower to secure the boat. I nearly used them before I decided to join the boat club. I'm glad I didn't.

I think it's a very good idea to drop the mast for boats of our size. It reduces windage and is relatively easy to do.

Finally, here's a pic where I added the triangle to show the load bearing tripod. It's pretty easy to visualize why it's better to have the stands behind the keel instead of in front:

<center>

</center>

Edited by - on

dlucier
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Response Posted - 11/06/2011 : 18:24:32

I don't believe the keel and stands 1 and 2 are forming a true tripod (equal weight on each). The keel is probably supporting the great majority of the weight with the others just playing a supporting role (pun intended).

I have a cradle and the forward legs are just ahead of the keel with the aft two closer to the stern. This is similar to the first stand layout you posted.

Edited by - on

John Russell
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Response Posted - 11/06/2011 : 18:45:48

My boats on a trailer, sitting on its keel with 4 pads on the hull. I don't recall the pads exact locations but, somebody here must have their boat on a trailer nearby for a few pictures. Since its the trailer that the boat was sold with, I assume the pads to be where Catalina's engineers thought best. Assuming the same weight distribution of most weight on the keel with the pads primarily there to provide balance, your stand placement would be the same.

So, anybody got any pictures of their boat on their trailer?

Edited by - on

OJ
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Response Posted - 11/06/2011 : 19:04:42

This picture doesn't help much because of the roller trains.

When raising the boat off the trailer (for bottom painting) I've always aimed for the forwardmost bulkhead and companionway bulkhead.

Edited by - OJ on 11/06/2011 19:10:13

Steve Milby
Past Commodore

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Response Posted - 11/06/2011 : 19:56:21

I think the flaw in your thinking regarding placement of jackstands is that weight distribution isn't the only concern. You also need to think about windage, and resistance to the wind. If jackstands 3 & 4 are placed aft of the keel, then jackstand 1 will prevent the bow from drooping, but it will provide almost no lateral resistance to the wind. In a strong wind, with no lateral resistance forward of the keel, the bow could rotate to leeward, twisting it off its jackstands. If jackstands 3 & 4 are placed forward of the keel, they will provide lateral resistance to any lateral movement forward of the keel. I've never seen any marina place jackstands in that manner, and don't think it would be safe in an especially strong wind.

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TakeFive
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Response Posted - 11/06/2011 : 20:14:10

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Steve Milby
 I think the flaw in your thinking regarding placement of jackstands is that weight distribution isn't the only concern. You also need to think about windage, and resistance to the wind. If jackstands 3 & 4 are placed aft of the keel, then jackstand 1 will prevent the bow from drooping, but it will provide almost no lateral resistance to the wind. In a strong wind, with no lateral resistance forward of the keel, the bow could rotate to leeward, twisting it off its jackstands. If jackstands 3 & 4 are placed forward of the keel, they will provide lateral resistance to any lateral movement forward of the keel. I've never seen any marina place jackstands in that manner, and don't think it would be safe in an especially strong wind.
<hr height="1" noshade id="quote"></blockquote id="quote">
Best point I've seen yet. Thanks! Something to think about (for a few days), and eventually to act on before the winds pick up. The middle pads are easy to relocate because they do not bear any weight. Fortunately I have trees close by to starboard, so lateral winds are slowed somewhat in my location.

I am not 100% convinced by your argument (I'm stubborn that way), but I understand what you are saying and am now 50-50. The really safe decision would be to buy two more stands, but I'm not there yet either.

The trailer comparisions are interesting. However, weight distribution could be very different due to the need to consider acceleration and deceleration at highway speeds. This probably requires a great deal of support in front to keep the boat from moving forward, especially if turning and braking at the same time.

Edited by - on

Voyager
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Response Posted - 11/06/2011 : 20:35:23

Wow - I think I have seven stands this year. The keel stands on a 6x6 block of wood.
One stand holds the Vee of the bow just under the aft end of the anchor locker, a pair are set forward of the keel chained together so that the chain touched the bottom of the hull, a pair is abeam of the keel with a chain led underneath the keel (there's a slot cut in the 6x6 and a pair under the stern, also chained together.

Before I venture into the boat, however, I check that all the stands are securely tightened up against the boat. Often when the stands settle into the crushed stone, some settle more than others. I have from time to time found a few stands absolutely slack! I generally alert the yard boss if things don't seem right. On occasion, if only one is slightly loose, I will retighten it myself.

Is it just me, or does the yard never get the deck absolutely level? It throws me off when I'm down below working on something and my screw driver rolls away!

Edited by - on

John Russell
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Response Posted - 11/07/2011 : 07:44:54

OJ's boat is a C25 which may me think of an important difference between it a C250 -- Interior bulkheads.

I didn't notice any discussion about the absence of bulkheads in the C250. It seems to me that the stands would be placed under the "sling" designations on the hull. These seem to correspond to the "stiffeners", for lack of a more accurate term, on the interior. The beam-like sructure that the compression pose is on is above the transverse seat. These provide some support to the hull. The bulkhead that separates the aft berth from the battery compartment does this as well.

I just re-looked at your diagram with 4 of the 5 stands aft of the keel. With that configuration, what happens if the nose stand should fail while you happen to be on deck forward of the mast? I think the boat would land on the bow in the gravel yard.

You're probably right about the stopping forces, etc., required on the trailer. But, wouldn't that extra requirement make the boat even more stable standing still?

Edited by - John Russell on 11/07/2011 07:51:55

Steve Milby
Past Commodore

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Response Posted - 11/07/2011 : 09:09:55

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by RhythmDoctor
 [quote] The really safe decision would be to buy two more stands, but I'm not there yet either.<hr height="1" noshade id="quote"></blockquote id="quote">
My C&C 35 weighs about 13,000 lbs and is supported on the hard by 5 jackstands. I have been at my marina for almost 10 years, and 5 jackstands are used for all but the biggest boats, and in that time, not one boat, from 23' to 40+ feet, has fallen off it's jackstands at my marina, even during a hurricane. Seven jackstands wouldn't hurt, but I don't believe they're necessary, especially for a 25' boat. My thinking is that 5 stands are the industry standard, and that's good enough for me. If the means of support meets industry standards, and it nevertheless falls off the stands, that's why I pay for insurance.

Edited by - on

Voyager
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Response Posted - 11/07/2011 : 10:01:22

It just means that when I'm bottom painting in the spring, I have two more patches to touch up!

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Stinkpotter
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Djibouti
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Response Posted - 11/07/2011 : 11:16:28

I agree with Steve's point on lateral forces. The keel becomes the pivot point in a big blow (or if a forklift backs into the boat), and the bow stand is not really up to resisting a lateral push.

As for the triangle, the weight supported by the two aft stands is the weight of the boat minus the weight supported by the keel (most of it) minus some fraction (need some trigonometry here) of the weight forward of the keel, which counterbalances the aft. Placed close enough to the transom or under an aft bulkhead, those stands should be adequately supported.

One last suggestion: Ask that "huge Catalina dealer" who came up with the original placement how they decided on it. They may be going on something Catalina suggests, or just their own vast experience... either would be useful to know.

Edited by - Stinkpotter on 11/07/2011 11:17:44

TakeFive
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Response Posted - 11/07/2011 : 20:52:04

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 I agree with Steve's point on lateral forces. The keel becomes the pivot point in a big blow (or if a forklift backs into the boat), and the bow stand is not really up to resisting a lateral push.

As for the triangle, the weight supported by the two aft stands is the weight of the boat minus the weight supported by the keel (most of it) minus some fraction (need some trigonometry here) of the weight forward of the keel, which counterbalances the aft...
<hr height="1" noshade id="quote"></blockquote id="quote">

There's one additional fact that I just now realized, and has me leaning strongly toward moving the stands back forward to the "standard" position.

I added 300 lb of ballast to the bow this season (to address the common bow-high problem with this boat), so the boat may now be quite a bit less stern heavy than it was last winter. It is quite possible that once I've removed the outboard and battery from the stern, when I walk forward on the bow, the boat may become bow-heavy. Without the side support in front of the keel, the stern could lift out of the four stands that are aft of the keel and twist around the keel due to the lack of side support in front. I think I'll definitely move those stands back before removing the motor/battery, and before walking forward on the bow again.

Edited by - on

dmpilc
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Response Posted - 11/08/2011 : 07:50:17

Here's mine on the trailer:

Since it's a C-25 and not a 250, I'm not sure it helps your discussion. Since most full keel trailers use 6 pads, for storage on the hard I might be inclined to use 6 stands with pads placing the 2 forward ones fairly close together. Given that I have a swing keel, I most certainly would use 6 stands since I can't rest the boat on the keel.

Edited by - dmpilc on 11/08/2011 08:04:22

Nautiduck
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Response Posted - 11/08/2011 : 19:58:13

Six pads on my trailer.

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TakeFive
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Response Posted - 11/14/2011 : 21:50:39

OK, so after looking at the trailers I'm convinced that if I were going to drive 60 mph down the highway, I'd want 6 stands and a nose brace. But I have 5 stands, so still trying to find the best way to set these.

Call me dense, but I still can't see placing them in front of the keel. The best argument I heard was that the windage of the bow would cause the boat to twist out of the stands. But given that the bulk of the weight is on the keel (and the point of greatest contact is the front half of the keel), you can see here that having the stands directly in front of or behind the keel really does little to prevent such twisting of the boat:

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My current hypothesis is that many other boats have the keel further aft than the C250, and in those cases putting the stands in front of the keel makes more sense. Boat yards are used to doing it this way, so they do the same for all boats of this size range.. But in the case of the C250, with the mast and keel so far forward, it makes more sense to put them just behind the keel. Plus, the bulkhead is there to provide added stiffness.

I'm still thinking it over, but every time I visit the boat I have a hard time visualizing it being more stable with the stands further forward.

I'll try to get some time to call and ask this week.

Edited by - TakeFive on 11/14/2011 21:52:33

Stinkpotter
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Djibouti
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Response Posted - 11/14/2011 : 22:07:00

Remember, probably something like 75-80% of the weight is on the keel, and about 20-25% is on those rear stands. The forward stands are there to hold the boat in a stable, upright position. Whether they're just forward or just aft of the keel, they're not bearing any significant amount of the weight unless you use them to lift the keel off its blocks, which of course you won't do.

I'll say it one more time: That "huge Catalina dealer" and boatyard does this for a living. Ask them. Then do it your way at your risk. But don't post photos--your insurance company could use them against you.

Edited by - Stinkpotter on 11/14/2011 22:10:49

John Russell
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Response Posted - 11/15/2011 : 07:36:40

I think you're overthinking this. Dave makes an interesting point about insurance. Should the worst happen, I'd imagine that any insurance company would ask whay you didn't follow the "industry standard".

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Steve Milby
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Response Posted - 11/15/2011 : 08:58:32

Put yourself in the place of other affected people. If my boat was next to yours, I would insist that either your jackstands be placed consistently with the yard's normal practices and industry standards, or that my boat be moved away from yours. I'd make the request in writing, to make it clear that I was making a written record, for future evidentiary purposes. If I was the marina operator, I probably wouldn't care if you damaged your own boat, but I wouldn't appreciate it if you annoyed my other customers, if you caused me inconvenience, or if your conduct created an unreasonable risk that I would get sued if you damaged someone else's boat. Finally, I'm trying to understand what harm would be done by placing the jackstands in the usual manner. I can't imagine how it would harm your boat, but, if there was a risk, then, if I were you, I would just buy two more jackstands and put them in place, even if I didn't think them necessary, because in doing so, it would allow me to support the boat my way, while satisfying the concerns of everyone else. I'd rather spend a few dollars than put my neighbors and the marina operator in a tizzy, just to prove my unproven theory.

Edited by - on

John Russell
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Response Posted - 11/15/2011 : 09:24:00

Gee, Steve, you sound like a lawyer or something.

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TakeFive
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Response Posted - 11/15/2011 : 10:30:59

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Steve Milby
 ...I can't imagine how it would harm your boat...<hr height="1" noshade id="quote"></blockquote id="quote">
Unlike the C25 and many other models of boats, the C250 has no bulkhead in front of the keel. The fiberglass can flex there when stressed. How's that for damage?

I'll probably move the stands to go "with the crowd," though I have yet to see any argument for it based on engineering principles. When I estimate the loads, the moment arms, the bulkhead locations, etc. everything tells me that FOR THIS PARTICULAR MODEL OF BOAT the stands would be more effective just behind the keel.

I can see an argument that placing the stands in front of the keel is better for other model boats that have bulkheads there, or for boats where the keel is further back toward amidships. Marinas will follow a standard practice for all boats, without taking the time to analyze the specifics of each boat. Boat yard personnel generally haven't studied physics or engineering mechanics, so they're not going to consider the specifics of each boat.

The prior argument about the boat twisting due to windage on the bow sounded good at first, but stands placed near the keel, whether just in front or just behind, are tangential to the rotation, and thus would not stop the boat if it was torqued by windage at the bow. The middle stands are only going to be effective at resisting a sideways force on the hull, and I still say that placing them behind the keel, closer to the center of mass and at a point where the beam is wider, will more effectively resist such a sideways force.

Bottom line is since we don't see a lot of boats tipping over with the "standard placement," it's probably redundant enough that it doesn't matter that much - certainly not worth the aggravation.

By the way, that huge Catalina dealer places their stands directly on gravel with no plywood underneath. Since they must know what they're doing, I guess that's OK also.

And nobody else's boat is at risk here. By dropping the mast every winter, I make the single most important improvement to reducing windage. The boat is solid as a rock where it is now, and will remain that way until I move the stands to the inferior, but more popular, location.

Edited by - on

John Russell
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Response Posted - 11/15/2011 : 10:58:09

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by RhythmDoctor
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Steve Milby
 ...I can't imagine how it would harm your boat...<hr height="1" noshade id="quote"></blockquote id="quote">
Unlike the C25 and many other models of boats, the C250 has no bulkhead in front of the keel. The fiberglass can flex there when stressed. How's that for damage?...
<hr height="1" noshade id="quote"></blockquote id="quote"> With the exception of the bulkhead ~12-18 inches forward of the transom, there are no bulkheads aft of the keel either. There are, however, structures inside the boat that provide some stiffening and they are forward of the keel. I mentioned the "beam" for lack of a better term, that the compression post is under earlier in this discussion. There is also the athwartships seat just below that beam. The "sling points" marked on the hull also provide and indicator as to where the manufacturer thought the hull would be capable of increased loads, also forward of the keel.
<blockquote id="quote">quote:<hr height="1" noshade id="quote">

......... Boat yard personnel generally haven't studied physics or engineering mechanics, so they're not going to consider the specifics of each boat.<hr height="1" noshade id="quote"></blockquote id="quote">Yes they have, just not in college and they probably don't call it that, they just call it experience.

By the way,
<blockquote id="quote">quote:<hr height="1" noshade id="quote">What do you guys think?
<hr height="1" noshade id="quote"></blockquote id="quote">
You asked.

Edited by - John Russell on 11/15/2011 10:59:41

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