Boat Lift Cradle design For a CD22?

Fishhawk

Our new boathouse will be going up next week.

There must be a number of y'all using lifts.

We're hoping not to have to re-invent the wheel and go through a lot of trial and error. I am very interested in knowing what type of cradle works best, where the boat rests best in the cradle, and where the center of gravity is on a 22 cruiser with twin 40's.

The lift will be a gear reduced 2" galvanized pipe centered over the boat with wraps of stainless cable and a pulley system that lifts two crosswise beams both fore and aft. Normally there are two double 2x10 stringers on edge tying the crossbeams together for the boat to rest on lengthwise. This is the most common system here on the gulf coast. How far apart should I have the 2 crossbeams built? How far apart should the stringers be?

As we will have fresh water available, it would be very convenient if the boat could be lifted after having backed up into the lift for flushing the engines periodically.

Sage advice please!!!

Dan

Wefings · Posted: Fri Apr 23, 2010 7:27 am Post subject:

Dan ,standard style bunk configuration should be fine , make it with enough capacity to include the possibility of a heavier boat in the future ,also consider resale of your property . I would do at least 8000 Lbs capacity and more if you can swing it . Make it as adjustable as possible for a vee bottom boat . Make sure it will holds a minimum of an 8'6" wide boat .Also have 120V available dockside for working on things,battery charging , heat for the boat for our polaresque southern winters etc. That would be what my thoughts are .
Marc

Papillon · Posted: Fri Apr 23, 2010 7:41 am Post subject:

Dan,
Will it look something like this...?

Fishhawk · Posted: Fri Apr 23, 2010 7:46 am Post subject:

Marc,

You must be seeing a CD25 in our future. Wink

Ol buddy, you'll be the first to know if/when that happens.

Ya, the wet portion of the boathouse will be 9 1/2' wide, 30' long, with a lift capacity of 7500 lbs.

I sure hope somebody can give me some measurements for the lift.

Dan

Fishhawk · Posted: Fri Apr 23, 2010 7:52 am Post subject:

Mike,

Almost exactly!!!! Good deal. Thanks much.

Can you get out your tape and shoot me some length, width, stringer spacing numbers?

How high is yours? We are allowing for 6' of air at high tide.

Dan

Captains Cat · Posted: Fri Apr 23, 2010 8:00 am Post subject:

Dan, do you have a bunk style trailer? Just measure those after checking if it rests OK on there. We also have that style of supports on our lift.

You can check out the construction of our stuff in my album. HERE

It shows both a CD22 and later my TC255 on the same lift.

Charlie

Walldog · Posted: Fri Apr 23, 2010 8:04 am Post subject:

Consider how much water you have at low low tide. A sling mount fits all easily and does not need as much water as the beams and bunks.

toyman · Posted: Fri Apr 23, 2010 10:42 am Post subject:

"Slings", as shown by Herb are the most popular around here. Water is pretty thin at times.

Fishhawk · Posted: Fri Apr 23, 2010 1:23 pm Post subject:

Charlie,

Our trailer has rollers. So no help there.

Thanks Texans, I have considered the sling option, but have plenty of water for the bunk style.

I think I can get what I need from Mike.

Dan

thataway · Posted: Fri Apr 23, 2010 1:47 pm Post subject:

The slings work fine for the C Dory 22. You will be fine by centering the bunks on the motors--this is where the majority of the weight is. The foreward lift can be about 12 feet in front of the aft cradle lift. Generally 70% of the boat will be on the aft lift--because of the engine weight. Be sure that the bunks come to the transom--to avoid a hook in the bottom. The cradle can be several feet in front of the end of the bunk. On the Tom Cat we doubled the bunk boards set on edge.

You are pushing the limits of a single lift at 7500 lbs. For that much weight most of us go to two motor lifts. The C Dory 22 will be fine with the single lift. The motor will be at close to capcity at 7500 lbs (even with the 2/1 ration of the cables. The major problem with single tube lifts is the inward pressure on the piles--and so you have do make double sure that the top of the pilings will not deflect inward (the pressure will warp even doubled 2x10's)--I had this happen with only a 5,000 lb boat on a single lift. My current lift has twin motors.

Consider cable winders on the tube--you can get by without, but it is much easier with the winders.

Caution: put rubber isolating material between any metal and the pilings or treated lumber. The treating material will eat into any metal, especially galvanizing or aluminum.

Also I am sure that you know that high storm surges damage hundreds of boats along the gulf coast when there are high water events. The boat rises up and us crushed under beams or the roof of the boat house. Sometimes the surges are far more than you anticipate. Be sure to take the boat out of the lift, and use a trailer to take it inland during a hurricane.

BrentB · Posted: Fri Apr 23, 2010 4:05 pm Post subject:

m2cw
Check the piling's diameter esp if planning future upgrades

One of our electric motors for a Davit lift was from
http://www.boathoistusastore.com/

They sent me their catalog and I thought it was informative

In SW FLorida, I buy items from Davit Master in Clearwater and Ace Lifts in Sarasota but I have davit lifts and my future upgrade plan is a inflatable unt

BrentB · Posted: Fri Apr 23, 2010 7:11 pm Post subject:

Make sure the electric motors are covered with a housing or a cover

thataway · Posted: Fri Apr 23, 2010 7:22 pm Post subject:

Brent's post about diameter reminds me that you need to be sure that the pilings are set with larger diameter in the bottom, and smaller up. Most installers put them in the opposite way, because it is easier. True, but it is also easier for the pilings to work their way back out during a storm surge.
The larger end down will also keep the pilings from settlng further.

If the pilings are being jetted in (as is often the case in this area)--then be sure that they hit them with some big sledge hammers before cutting the level for the tops. Best if they have a pile driver. Setting plings is hard work--we used to set our own--and our group still owns a setting barge, hoist and pumps. We just hire out the labor now....

BrentB · Posted: Fri Apr 23, 2010 7:55 pm Post subject:

Use piling barrier wrap around the submerged portion of the pilings

Fishhawk · Posted: Sat Apr 24, 2010 8:11 am Post subject:

Wow lots of good stuff coming out.

Thanks very much for all of your thoughtful responses. Bob, you amaze me again with your knowledge.

My contractor is a very experienced boathouse builder. In fact about 90% of the newer boathouses in the upper Bon Secour area were built by him.
He does jet the pilings and he does put the large end down. He does not wrap them though. He's working on a neighbors boathouse remodel right now and had to pull out some 15 year old pilings. There was some barnacle attachment on the 3 or 4 feet in the water but the 8 or 9 feet of piling that was in the sand and mud was pristine. He said because there is no oxygen down there.

Our pilings are 25' long. 12' will be above the water, 3-4' will be in the water and 9-10' sunk into the substrate. We are building a double boathouse with a neighbor that has a 25' Proline. There will be a shared pier between us which will save some space. Peak of the roof over the pier. There will be 16 of the 25' pilings holding up this building. Should withstand anything Ma Nature can throw at it.

Mike, can you post those measurements? I'll call ya if I need to, but someone else might benefit if you post em here.

Can't wait to get started.

Thanks again everyone.

Dan