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Remove bow ballast on the WK

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ruachwrights
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USA
258 Posts

Initially Posted - 05/26/2012 : 19:05:33

I know we all have heard it said that bow ballast will make the WK less tender, but I question the veracity of this knowledge. When it came time to get rid of the spare 150-200lbs of roof shingles I had in my bow compartment because the paper was mouldering as I examined them during my winter clean up project, I decided to launch this year without anything in the bow as an experiment. Granted, I did have a full water tank, but seemed to my wife and I that she sailed much better without the ballast. I was in maybe 10-17 kn of wind on Narragansett Bay with full sail on my tall rig and she sailed much faster and was less likely to round up. She also seemed much more athletic in lumpy seas than I remembered her- more able to surf.

Could it be that we non naval architect types have made a problem where there wasn't one?

Rounding up is typically a problem because the bow is driven under as a displacement hull reaches the limits of its speed- putting excess weight up there really would exasperate the problem-in theory anyway.

Any others out there want to experiment with me and share your results?

Vern Wright
Hajime

97 Catalina 250 TR/ WK
Hull #301
Attleboro, MA

Edited by - on

TakeFive
Master Marine Consultant

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Response Posted - 05/26/2012 : 22:12:36

My ballast was added to make the boat float on her lines. The design of the foredeck hatch requires the gutters to drain forward into the anchor locker. If the bow is high, the gutters drain backward and water accumulates (and stagnates) at the aft end of the hatch. No matter how good your gasket is, if water accumulates there it will leak into the V-berth.

So for me, adding ballast had little to do with how the boat handles. If you search the forums, you will see a lot of discussion of how ballast could affect handling. There is also some discussion of how rake affects handling, and recognize that removing ballast will also increase your rake. In fact, the differences you are seeing could be due to the rake change that comes with raising the bow.

One other benefit of having the bow down is much greater visibility to spot and steer around debris in the water. With the increased ballast, I can sit down at the helm much more than I used to.

So because of these practical effects, I'm not going to experiment with removing the rocks and sand that I placed in the bow. I'm happy with the handling of my boat, especially after the rake adjustments I made this spring.

Edited by - TakeFive on 05/26/2012 22:15:05

John Russell
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Response Posted - 05/27/2012 : 08:03:49

I've often wondered the same thing. I have ballast up there becasue it was there when I bought the boat and I deferred, since I didn't (don't?) know any better, to the comments made on this forum. Obviously, the advice given here is typically spot-on so why question it? With that in mind, I just left it there.

I'll look orward to reading your updates as the season progresses. Meanwhile, the ballast remains in my bow. Unfortunately, it also remains on my trailer this year.

Edited by - on

britinusa
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Response Posted - 05/27/2012 : 09:03:39

For us the ballast in our C250WB is to balance the boat foreNaft. However, she does seem to sail better when on her lines.

Our ballast is a water bladder, we rarely use that much water that it affects the balance.

Paul

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zeil
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Response Posted - 05/27/2012 : 18:24:38

And for us Hull #151 1995 vintage we use the space below the V berth to store about 6x25 500 ml, 72 ltr or 72 kilo ~ 150 lbs (20 gallon) water bottles.

The weight nicely balances the boat on her lines

Rarely do we use more than half during a cruise and often try to top it up or add larger 2 ltr bottles or whatever is available and is used mostly for mostly drinking, cooking, etc. For dishes, washing and miscellaneous the 22 liters 6 gallon) port side on-board water tank is used.

In a pinch we can get away with using one gallon per day tank water while using unlimited drinking water during cruises.

Edited by - on

ruachwrights
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Response Posted - 05/29/2012 : 07:22:13

Thanks for the post Rick. She seems to float only slightly off her lines with water tank full (at least when there is no crew aboard). Have not yet noticed leaking problem in the hatch but will keep my eyes peeled. Wondering if small holes paralleling the hatch cover could be drilled in the hatch grab strip to let water drain out into the cockpit? As for visibility I am tall enough at 6' and the boat small enough that visibility is not an issue. Since my family and I spend so much time on the ocean in her, performance is more important than small leaks anyway. And by the way we are not afraid of heel! However, the increased rake on the mast due to a less heavy bow increasing performance is an interesting idea which I had not heard of before though.

I am quite familiar with the threads. Alyrn Stewart, seems to be the principle initiator and sustainer of the idea that bow weight was helpful. As I understand it, at one point he hypothesized that the added weight in bow counterintuitively helped the boat to handle better because of the excessive beam aft, flatness of hull and possibly the positioning of the keel might make her spin in a gust (at least that's how I remember it). As much as I am thankful for his wonderful advice on many topics, he is or was a WB sailor. Also, 81/2 feet of beam is hardly excessive.

What I notice now that I have removed the ballast, is when the bow surges up off a wave and she seems to be on the verge of rounding up, she rights herself in the subsequent rocking-surfing- less bow-heavy landing. She also seems more resistant to "submarining" and the subsequent rounding up which I feel the added weight on the bow exacerbated.

Vern Wright
Hajime

Edited by - on

Arlyn Stewart
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Response Posted - 05/29/2012 : 10:02:34

Hi all... good discussion.

Trying to recall my memories... there were many evidences that played into my conclusions.

First some basics. Raking the mast aft moves the sail plan back and the balance point of sail and hull are affected so as to produce more sail plan yaw force aft, which generally increases weather helm.

Raking forward, generally decreases weather helm. Notable on the 250 however is that even while running a jib alone... the 250 can suffer adverse weather helm if it heels too far. Early on in the life of the 250, one owner had his forestay shortened significantly in an effort to reduce rounding up... and reported it didn't help much.

Given that testimonial and my personal awareness that the boat will round up when heeled too far under jib alone (with the first generation rudder) I don't think mast rake is the big player. It is important to note that the generation rudder was not an aberration as a too small of a rudder. It was a design following general area guidelines and would have worked on typical sailboat hulls. The aberration is that a much larger lift rudder was needed to provide stability.

The truth of this is born out by other manufactures of water ballast designed hulls having inadequate rudders such as McGregor and others.

For me, the direction to look was the hull form. Water ballast uses a unique hull form and the wing keel 250 inherited that hull form. The most notable feature is it has hard chines. More descriptively, it has a flatter bottom amidship that extends further towards the hull flanks before breaking harder to the flanks.

The reason for the hull form is simple... it gave water ballast designs the additional righting arm needed. But... there were unforeseen consequences to the hard chines.

Traditionally sailboat balance had been interpreted as the balance between the forces exerted by the sailplan above and the lateral resistance below. That definition proved to be totally inadequate because it didn't allow for other forces below. Thus, when water ballast hit the scene with its much harder chines... the effects were not well understood... specifically, the greater asymmetrical hull form footprint of the hard chines.

Simply put... when the 250 hull heels, it produces a greater asymmetrical footprint than a traditional design and consequently a greater lift force from that foil. That force must be added to the lateral resistance force... consequently the boat balance is affected greatly in ways that traditional sailboats weren't.

And... it is a given that the lift force has a center and that if it is different than the lateral resistance force, then boat balance is affected.

My argument for quite some time has been that the center of that lift force is well aft of the lateral resistance center so that when the boat heels increasingly the added yaw force has to be countered by an over sized rudder.

The trimming the bow down comes into play as follows... it moves the center of that heeled footprint or foil forward where the center of its effort is closer to the lateral resistance balance center thus reducing the yaw lever couple. The benefit is a reduction in what is called 'monster weather helm' where a strong puff suddenly blows the boat to 25-30 degrees of heel and rounds it up with inadequate rudder to hold it or a rudder lifting and digging so hard and creating so much turbulence that the boat slows.

Last... adding weight to the bow was not my idea, I'm not that smart. My theory did not exist until after several others had done so for other reasons such as gutter drainage or looks, saying... "guess what, doing so helped reduce monster weather helm." And... that happened after the wing keel came online because it suffered the water line trim problem worse than the water ballast perhaps because it is a lighter boat.

I took those testimonials at face value as honest assessments. If they prove to have been errant... then my theory is debunked. But... before doing so, another story. After I had proffered my theory, I discovered and exchanged several emails with a Brit who was big into one meter RC racing. He had written some comments about monster weather helm that paralleled my observations on the 250. He had been designing increasingly hard chines to improve righting arm and stumbled into exactly what seems indicative to the 250, that trimming bow down brought relief to the monster weather helm that resulted from the hard chines.

An interesting aside is that Vendee Globe and other designs that are always in search for greater righting arm have even come up with hull designs that produce an asymmetrical footprint with lift to weather rather than leeward.

Last... my theory... any theory is what it is... conclusions based on a scenario that will fit and explain the circumstances. There is no desire to conjure the circumstances. If there are equally reliable evidences that trimming the bow down is counter productive to easing monster weather helm on the 250, I'd certainly take note and withdraw my theory.

btw, normal sailboat theory does say that trimming the stern down, increases lateral resistance aft thus decreasing weather helm. I get that completely and have proffered that what is happening is a net result that the benefit of the asymmetrical force moved forward is greater than the benefit of the lateral resistance aft.

Edited by - on

Arlyn Stewart
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Response Posted - 05/29/2012 : 10:31:28

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by ruachwrights
 Thanks for the post Rick. She seems to float only slightly off her lines with water tank full (at least when there is no crew aboard). Have not yet noticed leaking problem in the hatch but will keep my eyes peeled. Wondering if small holes paralleling the hatch cover could be drilled in the hatch grab strip to let water drain out into the cockpit? As for visibility I am tall enough at 6' and the boat small enough that visibility is not an issue. Since my family and I spend so much time on the ocean in her, performance is more important than small leaks anyway. And by the way we are not afraid of heel! However, the increased rake on the mast due to a less heavy bow increasing performance is an interesting idea which I had not heard of before though.

I am quite familiar with the threads. Alyrn Stewart, seems to be the principle initiator and sustainer of the idea that bow weight was helpful. As I understand it, at one point he hypothesized that the added weight in bow counterintuitively helped the boat to handle better because of the excessive beam aft, flatness of hull and possibly the positioning of the keel might make her spin in a gust (at least that's how I remember it). As much as I am thankful for his wonderful advice on many topics, he is or was a WB sailor. Also, 81/2 feet of beam is hardly excessive.

What I notice now that I have removed the ballast, is when the bow surges up off a wave and she seems to be on the verge of rounding up, she rights herself in the subsequent rocking-surfing- less bow-heavy landing. She also seems more resistant to "submarining" and the subsequent rounding up which I feel the added weight on the bow exacerbated.

Vern Wright
Hajime

<hr height="1" noshade id="quote"></blockquote id="quote">

Hi Vern, I wanted to address this portion by itself. I appreciate greatly your description of what is happening and accept them as very observant. You are quite right in that there are two differing boats involved. For as long as there has been keeled boats, there has been chatter about the comparison between a full and center keeled boat. A full keel suffering a seaway better than a center keel but a center keel much more nimble and needing less ballast.

The water ballast is truly more like a full keep boat. It suffers less hobby horsing and thus pounding and digging and having never sailed the keeled 250, I can only guess at the comparison due to my observations from a good bit of time on a C30 wing keel, which hobby horsed and was much wetter in a seaway than the 250 water ballast. Without doubt, as to the ride the c250 wb is a smoother ride on Great Lakes weather than was the C30 wing keel.

I've no doubt that trimming the bow down by adding forward weight increases hobby horsing in a seaway on a center keeled boat. It has been long understood that center keelers suffer from doing so and many testimonials can be read where anchor chain was moved from near the bow to the center of the boat to make a center keeler dryer in a seaway.

The hobby horsing nature however is a different animal than monster weather helm so let me be the first to stipulate and accept what you say about digging in and pounding to be exasperated by trimming the bow down.

I just want to be sure we keep the two issues separate.

Edited by - on

Nautiduck
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Response Posted - 05/29/2012 : 15:20:34

I'm leaving my ballast (5 X 55lb) for two reasons:

1- I like Arlyn's reasoning.
2- I'm getting too old to lift 55lb bags of rock out of the bow.

Other than the ballast the two things I have done that really help the weather helm are replacing my rudder with a deep, balanced one from IdaSailor, and reducing sail when she starts to show signs of being overpowered. In good winds these boats are faster with a smaller sail plan. Once I figured that out we got to moving very quickly in strong winds and enjoying it much more.

Edited by - on

ruachwrights
Captain

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USA
258 Posts

Response Posted - 05/30/2012 : 07:01:33

Thank you Alyrn for the clarrification. Asymetrical chines at heal and the lack of a full rudder on earlier boats are good explanations. For now though I'm pleased with the way she handles- which is to say in my fantastic nautical vocabulary, "more surfey". The main reason I posted this was to see if I could get a more objective perspective- i.e. dupe someone who has already been sailing this year to take their ballast out and see if they have seen the same results I have noticed;) On our annual family cruise when I will inevitably be filling up that now empty bow compartment with extra water, wet clothing or unruly teenagers I will be able to have a more objective point of view myself, but that won't me until later in the season.

By the way- which rudder do I have? It seems to extend to the same depth of my keel.

Vern Wright
"Hajime"

Edited by - on

TakeFive
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Response Posted - 05/30/2012 : 08:48:32

Vern,

Let me propose a different hypothesis for your "more surfey" performance.

Adding ballast to the bow does more than just alter the static balance by weighing the bow down. It also increases the moment of inertia of the boat, thus reducing hobby horsing. Note that water ballast C250 and/or a full keel boat both have higher moment of inertia because ballast is spread out from bow to stern. On the WK version, where the weight is concentrated amidships(thus lower moment of inertia) and a little lighter overall, adding ballast in the bow and passengers/motor/batteries in stern have a similar effect of increasing the moment of inertia.

When disturbed by chop, waves, wakes, or swells, every boat has a resonant frequency (or, more accurately, a harmonic series of multiple resonant frequencies) at which it will want to respond by pitching forward and back. If the disturbance is at the resonant frequency, the boat will hobby horse uncomfortably. If the disturbance is at a different frequency, the boat's hobby horsing will be damped out.

For example, I sail in more protected waters and never get swells. I do frequently get short chop and large wakes (especially from lone tug boats that are far exceeding their hull speed). These are relatively high frequency (low wavelength) disturbances that used to really toss my boat around. Since adding more ballast, my boat cuts through the chop and wakes, which is much more pleasant.

Your description of "lumpy seas" and your bow getting driven down under sounds more like low frequency swells are causing your boat to pitch-pole into them. Taking the ballast out increases the resonant frequency, making it appear more nimble in responding to the swells and allowing it to "surf" better.

So the improvement that you are seeing may be an effect of matching your boat's characteristics to the type of waters that you sail. There may be no single best configuration (ballast vs. no ballast), but rather a matching of the configuration to the prevailing conditions in your area.

So how does all this affect heel and rounding up? If a boat is not properly tuned to the prevailing conditions, the boat will encounter more drag and sail slower. A slower boat will heel more, because the power of the sails pushes the mast sideways instead of forward. And then more heel translates to rounding up because the heel pulls more of the rudder out of the water.

So tuning your boat's resonant frequency to the prevailing conditions gives a more comfortable ride, better speed, less heel, and less rounding up. But it sounds like the question of ballast vs. no ballast may depend on where you sail. So even if someone else duplicates your experiment, the results may not hold unless they have similar seas to what you sail in.

Edited by - TakeFive on 05/30/2012 09:20:03

Tony C
Deckhand

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Response Posted - 05/31/2012 : 12:52:03

Good topic. Has anyone considered moving the battery, on my 250 wk (2005) it is located right at the stern under the fuel locker. I was planning on moving is forward next to the water tank in the V berth to accomplish 2 things. 1 - Move weight forward, I think it will have double the effect by moving weight forward not just adding weight. 2 Make access to the battery easier.
I am interested in any input on this
Thanks
Tony

Edited by - on

Nautiduck
Master Marine Consultant

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Response Posted - 05/31/2012 : 19:52:41

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Tony C
 Good topic. Has anyone considered moving the battery, on my 250 wk (2005) it is located right at the stern under the fuel locker. I was planning on moving is forward next to the water tank in the V berth to accomplish 2 things. 1 - Move weight forward, I think it will have double the effect by moving weight forward not just adding weight. 2 Make access to the battery easier.
I am interested in any input on this
Thanks
Tony
<hr height="1" noshade id="quote"></blockquote id="quote">

Tony, that is a popular mod due to the reasons you cite. Here is one example:

[url="http://www.elmhurstprop.com/webbat/Photos.html"]Two batteries in bow[/url]

Edited by - on

ruachwrights
Captain

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USA
258 Posts

Response Posted - 06/09/2012 : 19:11:18

After several more sails, I'm sticking to my guns. Had three 150lb teenagers on the bow today and I'm certain that a ballasted bow is not great for sailing unless you like driving trucks with bad suspension. Granted 300 lbs may just be plain overkill. Even so, I have had her out many times now in stiff breeze with big seas and stiff breeze on flat conditions and all of my weather helm issues have disappeared -after removing ballast from the bow. Have had her over so far that the rub rail was in the water and she was still tracking without rounding up. Thought crossed my mind that rounding up is better than a knock down any day. Last year with ballasted bow I was fighting weather helm all the time. Also this chines are hardest from bow to mid point. They soften considerably in the stern. More weight in the stern should help her sail better.

Wish the designer of the 250 wk would weigh in here!

Vern Wright
"Hajime"

Edited by - on

Arlyn Stewart
Master Marine Consultant

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Response Posted - 06/10/2012 : 08:30:57

Generally speaking, one wants to trim the bow down in light air and the stern down in heavy air. In light air, a dragging stern is a very slow boat. In heavy air, a bow down crashing into the swell is slow and wet and on a cat... is in danger of a pitch pole.

Edited by - Arlyn Stewart on 06/10/2012 08:31:36

GaryB
Master Marine Consultant

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Response Posted - 06/10/2012 : 10:29:37

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Arlyn Stewart
 ... and on a cat... is in danger of a pitch pole.

<hr height="1" noshade id="quote"></blockquote id="quote">
Just to clarify, "...on a cat" refers to a catmaran not a Cat 25/250.

Edited by - on

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