Dock Damage
 

I was reading this morning in the Manchester Union Leader that 3.7" of rain has fallen in the Lakes Region since Jun 2 and that there are numerous instances where damage has been done to docks in the area due to high water levels and wave/wake action. I vaguely remember reading a few years ago that it is possible (as unbelievable as it seems to me) that Winnipesaukee can be lowered by 1" in a twenty four hour period via the Winnipesaukee river (?). I wasn't at the lake last weekend however observed the previous weekend that the bottom of my cantilevered dock on Rattlesnake was only 3+ inches above the lake's surface at that time...so obviously I'm concerned. Have the floodgates in Paugus Bay been opened? Does anyone know what the current lake level is (or how I can find out) and how much it has risen since Memorial Day weekend? Have the winds been high on the lake throughout this period?

Yes the winds have been howeling and all the lakes are very high. As high as Winnisquam is I doubt you will see much release from Winni.
I was working down on Blackbrook Rd yesterday and saw waves crashing over docks on Winnisquam and boats getting hammered pretty bad. I've heard reports of boat coming loose on winni.

Here's a link to DES
 

Here is a link to DES's website. Full lake is 504.32 (I think the decimal is correct) and every increase/decrease of .083 is approximately an inch.

http://www2.des.state.nh.us/rti_data/wein3_TABLE.HTML

There is also a thread on Lake Level that has a phone # that you can call to get the levels. It gives the level as 4.61, for example, meaning 504.61.

Hope that helps.

The lake is up about 3/10 foot from last Friday, about 3.6 inches. So your dock is awash right now, expect this once or twice a year. Decking needs to be secured to the dock frame as even higher docks will be impacted by wave action when the lake is high. It has been much higher than this in past years.

You can see the Lakeport out flow data here:
http://www2.des.nh.gov/rti_home/stat...E=Lakeport+Dam

Outflow regulation is a balancing act of Winni levels vs flooding the downstream lakes.

Weigh down the dock !
 

If your dock looks like it may float, a helpful temporary fix is to add extra weight. I have found the simple way to weigh the dock is to place large plastic trash barrels along the dock surface and fill them with water from the lake using a 5 gallon pail. No rocks or cement blocks to move on or off the dock top. And once the water level recedes, just empty them back into the lake. Will save a love of back breaking work and the added weight to prevent floating is substantial.

More Dam Information
 

http://www2.des.state.nh.us/rti_home...asp?name=winni

Rgilfert... I will hopefull take a ride today and will look at your dock. I am on the island all week and have watched the lake rise... A tad too high for my taste.

They can lower the lake very quickly if they had too. The problem is handling the out flow from Winnipesaukee. I have looked this morning and they have opened the dam to around 1350 cfs. The lake should start to react to this out flow, unless we get another deluge of rain.

Unfortunately most docks, where not build, with the ability to deal with water higher then full lake. a big oops in my estimation. With the lake at is current height the water is right at the bottom of my dock. Floor boards must be secured at this point, for the waves will lift them.

The lake level now is at the point, where I will put wieght on the dock this coming weekend.

If you look at this Bizer chart

http://www.bizer.com/bztnews.htm#lakelevel

You will see that pretty much every year has at least a week of water above today's level. If your dock survived them, it should survive the next week.

Consider yourselves lucky...
 

Not that many will care because its not Winni but over here in the lakes region of Maine things are in dire straights. Sebago Lake has come up over 19 inches since Memorial Day. Many dock companies are out straight trying to raise and/or remove docks before a heavy wind comes up. Several boats around the lake have sunk due to 9 inches of rain over the weekend taxing bilge pumps and boat batteries to the limit.

The Maine Dept of Conservation and Recreation has closed the locks at the Sebago Lake State Park and opened the flood gates attempting to drop Long Lake and Brandy Pond by some two feet. The problem with this is all that water flows into Sebago which is already 3 inches above "full pond". Exacerbating that is the only outlet from Sebago is via a dam into the Presumpscot River which has been in and out of flood stage the past few days so the outflow is being controlled.

Not a good situation at all. The lake is rising at nearly an inch every 5 hours with no end in sight.

BT

Thanks to All !!!!
 

This is all extremely helpful information and guidance...thanks to all who posted! I'll be out to the island Friday afternoon for the weekend and will start to get some weight placed out on the dock

I believe you said the dock is Cantilevered. That means there are NO Legs under it to support Extra weight. Extra weight may be counter productive. :look: Just wonderin.. NB

Arrrgh! Good thinking........I hadn't thought of that!

We recently replaced all the sections of our old wooden plank removable dock boards on one of our finger docks with composite. One of the benefits of composite is it does not float so it should stay in place better should the water rise above it. It's a little heavier than wood so each section is one piece smaller than the wood section was to reduce the weight when removing for the winter.

If you ever need to replace your removable dock boards, this may be something you want to think about.

Dan

The only trouble with the composite is it can mold. We went to all plastic.

Was there a particular reason Why the dock was built as a Cantilever design..? Is the water at the end of the dock VERY deep..or was it done that way for Permitting reasons. Can you describe the construction..How is the inboard end anchored..? Are the major structural members (Not the decking) made of Wood, Aluminum, or Steel..? :look: NB

Well, if you fill the barrels of water and set them on the dock....When, you empty the buckets back into the lake...won't that raise the water level again ?


Ha ha....just kidd'n....Guess I'll stick to my motor home and traveling on dry land...

Dock Construction
 

NoBozo...I don't know the reason that the dock was built with a cantilever design. I've only owned the place since mid last Sept. For Rattlesnake the water in front of our property is surprisingly shallow (we have a 45' breakwater and the water at the end is only 4.5' deep). I've only been in the water once since we bought the place (I dropped a 9/16" socket in the lake while installing dock cleats last fall and had to retrieve it)...but while in the water I noticed that there are three very large (approx 16" in diameter) sections of tree trunk projecting 4' out from the breakwater. Two 40' long 4" x 8"s run perpendicular on top of them with a 2" x 8" running parallel to them in the center. The dock decking is made up of 4' long 2" x 8" pressure treated dimension lumber on top of the 3 rows of "joists". I do not know for sure how the 3 sections of tree are anchored in place.....I assume that they are imbedded in the breakwater (?). There are five verticle 4" x 6" x 6' posts that are lag bolted to the outside of the 4" x 8" rim joist. None of the posts touch the lake bottom and thus are not very sturdy (and actually move quite freely side-to-side). I intend to replace these posts this summer and secure the new ones with carriage bolts (versus lag bolts). Am I allowed to embed the new posts in the lake bottom...or is that prohibited for some reason?? BTW.....this photo was taken on 5/12/2012....and you can see that already the lake isn't that far below the dock!

rgilfert, that looks just like our fixed dock, a common design. The three 16" dia tree sections are probably cut from telephone poles and are anchored in the breakwater. The 4X8 frame would have been bolted to the sections of telephone pole. The decking would be screwed down to the frame. Nothing will float away if it has not been dislodged by ice.

Our posts are attached to the frame with carriage bolts and they do sit on the bottom. We remove the end two posts for winter so moving ice does not grab them and damage the dock.

To answer your question on the Cantilever desighn. When the breakwaters were built on the islands and main land areas years ago most people didnt have electricity. Also people didnt run circulators each winter to keep the ice from forming around the docks. So when the breakwaters were built they built in the Cantilever posts and built the docks over them so when the ice formed it had no direct contact with the docks. The tie off posting was installed so it was above the water line so that also could not be damaged by the ice. Now if you replace your posting and bring it down to the lake bottom and dont run a circulator the ice will tear if off the dock. Looking at the pictures its level and looks in pretty good shape. The Cantilever posting looks level and thats great since there part of the breakwater. If have any questions on how to maintain the dock you can have one of the local dock companys come out and tell you what you need to do.

rgilfert: That's a pretty solid looking dock. As Slickcraft mentioned, the uprights on HIS dock go right to the bottom. I have seen uprights on the dock where I stay during vacation, just like yours..ie Not touching the bottom..they also wobble more than I would like. In addition, they are only Nailed to the facia. I think the Idea is to be "Break Away" if the ice gets hold of them.

I would do like Slickcraft has done..fasten with carriage bolts..BUT I would Remove ALL the uprights in winter. (Circulators on rattlesnake probably are not practical because of power outages.)

With the uprights Solidly on the bottom you can add some weight to the deck to keep it from floating UP off the T-Phone poles...IF that were likely. I'll take a guess that the T-Phone poles are embedded in concrete beneath the stones, which would also help to hold the breakwater together as well. :look: NB

By the way, I made an error is saying that I use carriage bolts to secure the posts to the 4X8 frame. In fact I use 5/8" galvanized hex head bolts so that they can be removed each fall after removing the decking strip next to each post. You will have to counter-sink the hex bolt heads on the outside of the post. Carriage bolts will lose their purchase making removal difficult.

Photo shows damage from ice sheet that came in from the south and took hold of the posts two years ago.

If the concern is that the water will lift the dock sections off the structural framing, then you can solve that by installing hurricane straps, linking each component to the next.

Any lumberyard will have them in stock. Long straps wrapped around the poles to the beams and then "hurricane clips" from the beams to each deck joist.

The hurricane clips you would need would be the H2.5AZ's or the H1's: http://www.strongtie.com/products/connectors/H.asp

The strap for the pole to beam connections: could be as simple as a metal band wrapped around and attached at each end to the cross beams or a cable system. Just don't use eyelets that you would buy at the hardware store, they are not rated and will likely fail if tested by uplift (not likely given the pictures.

For the posts, I would not bed them in the lake bottom for reasons of ice damage and water saturation fatigue in the posts. If you are looking for a simple system that will add a structural element to them (for boat tie off) then I would suggest using these: http://www.strongtie.com/products/connectors/dptz.asp Bolt the plates to your joists and use structural screws (GRK Screws)to anchor into the post. The beauty of this system is that you will have the ability to remove the posts without having to remove the carraige bolts (requires getting into the water). Use two connectors per post. You can paint these connectors black and it will add a nice clean and finished look to the install.

All hanger nails need to be rated Can't Sag Nails i.e. Joist hanger nails. Leave the common 8D's in the box for this project.

Also add your post padding to ensure that nothing is able to scratch up the boat.

Dock is fine, rgilfert
 

I went by your dock yesterday... It is fine... Water is high here, though!

At times like this, I wish my dock was as safe as your's is.

Dimensional Wood Supports NOT a Good Idea...
 

This dock had supporting 4x6s from the breakwater. :(

Telephone poles sound like a good upgrade. :look:

One way to get some telephone poles for free is to ask at the electric utility or telephone company for poles damaged by weather or automobile accident. Sometimes, they have these broken pieces of telephone poles left over from damages.

Just be careful that they are not poles treated with creosote or other preserving agents - not healthy for the lake.

I would not use polls from the telephone company, they are most definitely treated. Older one with creosote as mentioned. Other with new fangled treatment that are supposed to be more environmentally friendly but still harmful to the lake.

As for stability of post on the cantilever docks I have a few suggestions..

--- one if you plan on removing the posts every year as you should, you could always create a footing that you could put the end of the post in that sits on the lake bottom and is heavy enough to help stabilize things... remember however it most be removable from the water.

--- The second is to brace from the bottom of the post back up to the far side of the deck frame. This would be my preferred method....

The WeatherCam's site displays the latest lake level reading also. It's only the number and not a graph like Bizer, but it gives a basic idea of what's happening. Also, in the WeatherCam's view, when the water is calm, you can see only ONE tiny bit of Black Cat Shoals showing if the lake level is officially full. No rocks at all means it's above-full. More rock(s) and it's below-full.