Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 28-11-2010, 08:50   #16
PAR
Registered User
 
PAR's Avatar

Join Date: Jul 2010
Location: Eustis, FL
Boat: 1960 Chris Craft, 1957 Clyde, 1961 Atkins, 1986 Macgregor 65, plus three of my own design and build
Posts: 239
Images: 2
Send a message via Skype™ to PAR
A two strap lift wouldn't be recommended as this places a lot of point load on each strap. The ballast casting on this particular design carries a high percentage of longitudinal stiffness in the hull. This is a trick L. Francis learned from his father and one he bragged about and used in many designs. Without the ballast the hull is "floppy" especially fore and aft. This is why you don't want a two sling lift. A three sling would be much better, maybe an "I" beam temporary attached along the keel too, to keep the hull from doing something weird, like rip the deck carlins and sheer clamps out of their respective locations.

The logical locations for a 3 strap lift would be the aft strap at frame bay 41, which is right at the very end of the flat portion of the deadwood assembly. This is the thickest portion the deadwood assembly and being under the aft end of the cockpit and just forward of the mizzen, a fairly solid location. Next and would seem the natural location is frame bay 28, directly on the frame, which is the CG location too. It's also under the forward end of the trunk cabin so a full width deck beam, mast step and fuel bunker bulkhead are located. The last would be frame 13.25 (the one after frame 12), which is located just under the forward side of the fore mast step. This is on the angled up portion of the hull in the forward quarters, so you may want to rig a preventer to keep it from "creeping".

If the ballast casting was in place you could use a two point lift and place the straps at the very locations L. Francis intended for the steamer hoist. If a temporary "I" beam was installed, you could also use these two point locations, which are shown on the plans.

I mention this because the 3 1/4" deep keel timber, isn't all that much material to be asking to support the 10 tons of 55' monster on top of it. The only areas of the keel that have much meat are the hoisting ring locations and the "posts". My point being a two sling lift will likely hog the hull if too close together or rip out the sheer clamps and carlins if too far apart.

A set of gantry style hoists could be rigged, possibly motorized, each set at the locations I've mentioned. If it was me, I'd make a really stout cradle for the boat and hoist the cradle with the boat in it. This way the boat doesn't really come into play, assuming the cradle is truly stout. This cradle could be used over and over during your other planed moves.

Lastly, I have a home made power chain fall. It's a regular 3 ton chain fall, but I've rigged up a wooden gear to accept the hoisting chain. The wooden gear has an in feed and out feed guide of sheet metal and the whole 2 pound contraption is run by an electric drill that I chuck up to it. Just keep tension on the chain and it'll run up what ever you hang from it. I could easily see a long bit of pipe with three gears attached, all threaded through the hoisting chains of three gantry hung chain falls. One electric motor with a speed controller, maybe stolen from a router table. Yea, a bit of contrivance, but nice, uniform control with more heft then necessary, just in case your local experts where way off.
__________________

__________________
PAR is offline   Reply With Quote
Old 28-11-2010, 11:05   #17
Registered User
 
jimships's Avatar

Join Date: May 2009
Location: Houston, Texas
Boat: Herreshoff_Marco Polo 55_Majesty
Posts: 26
Self Elevating Cradle.

Without her ballast, frame position 27 looks to be about right for a hull CG. She is to original design in all cases except the bulkheads are a bit more timber than called for. I will need to reinforce this as they are not edged and will need some cross hull supports in addition to deck frames.

I am OK with the 3 strap lift suggested in place of 2. Actually I like the suggestion better as it makes for a more distributed lift and reduces single line loads.

Our good ol trucker has me thinking about simplicity again. "Getting the job done with the least effort".

I have several 20Ton jacks and I could get them under her for sure with 1" plates. Using multiple sailboat jack stands for supporting the full hull weight as you move a cradle under her is a questionable as this places all the weight on the turn of the bilges and not the keel, but she is very stout at 1 7/16" hull thickness and she has bulge stringers at the turn. Maybe I am being over cautious and should work with about 8 stands and 3 bottle jacks. However, stands would need to be custom likely as they are over 8' tall and should have have the ability to increase height about 2'. This is asking a lot for any stand and they are definitely not stock stands.

No. I as I wrote the above, I need to lift a different way instead of bottle jack her up. Something about being under her while all this is going on is a bit unsafe. I like to be where I can run if I hear sounds that mean trouble. hhhhhhhhhh.

OK so back to gantries of some kind with strap lift or a "self elevating cradle", (i.e. a poor man's Hostar without being a Hostar).

The "self elevating cradle" sounds like a plan, but getting a fixed welded steel cradle under her in the first place is just as hard a putting the boat in the air on straps so no gain unless the cradle can be made as a "tuning fork" design. Removable intermediates and end steel. (i.e.Hostar design).

Now, this new design allows easily placement of the cradle under her with little effort and you can set everything up to support hull equally. Then, because the cradle has the trackers jacks needed, (maybe 6 total, 3 per side), you can lift her to the sky, drive the DD trailer under her and set her down like you know what your doing. hhhhhhhhh Jack legs would be removable and slide into cradle receivers and use pins or bolts to keep in place. You could even reposition the load as needed once she is outside and on hard ground. Might be just the right plan for going down the road in support of the hull and the lift.

I am off to the drawing board to sketch this out.

Comments ideas, suggestions. You are wrongs, or you are rights?

Thanks again.

Jim
__________________

__________________
jimships is offline   Reply With Quote
Old 28-11-2010, 17:20   #18
Mooderator
 
capngeo's Avatar

Cruisers Forum Supporter

Join Date: Jul 2010
Location: Key West & Sarasota
Boat: Cal 28 "Happy Days"
Posts: 4,211
Images: 12
Send a message via Yahoo to capngeo Send a message via Skype™ to capngeo
I see what you are trying to do.... I built something a while back you might be able to modify to your needs... lemme see if I can find pix of it... If I can't I'll sketch it out
__________________
Any fool with a big enough checkbook can BUY a boat; it takes a SPECIAL type of fool to build his own! -Capngeo
capngeo is offline   Reply With Quote
Old 28-11-2010, 17:46   #19
PAR
Registered User
 
PAR's Avatar

Join Date: Jul 2010
Location: Eustis, FL
Boat: 1960 Chris Craft, 1957 Clyde, 1961 Atkins, 1986 Macgregor 65, plus three of my own design and build
Posts: 239
Images: 2
Send a message via Skype™ to PAR
As I mentioned above, the Marco Polo hull uses the ballast casting as the lower portion of the "hull girder" or truss if you will. It bears the vast majority of longitudinal loads on the bottom side of this truss. Without this structural element in place the hull is easily distorted, twisted, hogged, droop bellied, etc. I can't tell you how big a deal the ballast casting is in this design, but again just note the physical dimensions of the actual timber keel. It's 3.25" thick and this frankly isn't diddly squat for a structural element that must resist these forces as she's lifted, mostly likely out of plump and with preferential loading. Bolt an "I" beam to the keel then the problem goes away. Better yet is to properly support her in a cradle and lift the cradle. Done properly, you can place rollers under the trailer skids and glide her right up onto the back of a flat bed, all the while the keel has seen very little loading.
__________________
PAR is offline   Reply With Quote
Old 16-12-2010, 07:11   #20
Registered User
 
jimships's Avatar

Join Date: May 2009
Location: Houston, Texas
Boat: Herreshoff_Marco Polo 55_Majesty
Posts: 26
I did some rough calculations with the lines plan. She's 11'1" at bow point with her sitting on 16" blocks. Height is an issue.

The cradle is being reworked for the "tuning fork" design so we can get her under the hull and make a multi-point lift, one 15" step at a time. The ground contact points will be at 10' spread in width...about equal to the gunnel beam and more than enough for the 8'6" trailer to get under. The hull supports will be positioned at around 6'6" and placed along bulkheads. The "landing gears" will have double steel wheels so boat can be positioned best laterally or move her forward for the truck trailer. Looks like the height is the most critical issue now. A double drop is best at 18" deck, but only have a single drop so far at 36" deck. The saga continues.
__________________
jimships is offline   Reply With Quote
Old 17-01-2011, 19:40   #21
Registered User

Join Date: Jan 2011
Posts: 1
Jim, Im a new member so late to this thread. Have you done the lift? I wanted to wave because I am currently restoring a marco Polo myself. There arent many of us around and I thought I had hunted everyone but Majesty is new to me. Is there a thread with more about her? Ours Is Ile Ola out of Geelong, Australia 1956.
__________________
Bonnie Larkin is offline   Reply With Quote
Old 17-01-2011, 20:57   #22
Registered User
 
Unicorn Dreams's Avatar

Join Date: Aug 2007
Location: Clear Lake Marine Services - Seabrook, Texas
Boat: Gulfstar, Mark II Ketch, 43'
Posts: 2,359
Just call a boat mover to come out and take a look.
As mentioned above, some boat moving trailers are hydraulic drops in the middle that can open up and back under the boat, replace the cross members, jack the trailer center back up and then boogie on down the road.
__________________
Formerly Santana
The winds blow true,The skies stay blue,
Everyday is a good day for SAILING!!!!
Unicorn Dreams is offline   Reply With Quote
Old 18-01-2011, 05:47   #23
Registered User
 
jimships's Avatar

Join Date: May 2009
Location: Houston, Texas
Boat: Herreshoff_Marco Polo 55_Majesty
Posts: 26
Hello Bonnie and Unicorn,

Unicorn first. Good to find someone in the Houston area with a nice sailboat. Hi let's talk more.

Bonnie: She has a great history and some of it I posted here. Never been finished in 27 years and in inside storage the whole time. I am making some headway. I need to move here 3 times I believe. We have these things called Hurricanes here. The problem is that she is in a tight warehouse and we are working on solutions to lift and solutions to roll down the road. I can build the trailer for her for about 10K. A haul is about 6K-7K. It makes sense to build the trailer and then lease it out to others who need a big rig.

If you have a list of owners I would appreciate it. Back to to jimships@yahoo.com.

How far a long are you in your restoration? What configuration is she and did you keep to the original design or modify?

Thanks to you both.

Jim
__________________

__________________
jimships is offline   Reply With Quote
Reply

Tags
arc

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hello from Newbie, 55' Samson Ketch Joeblack5 Monohull Sailboats 13 15-03-2016 16:16
Sailboat Transport Reluctantsailor Dollars & Cents 3 12-08-2010 07:40
Place to Keep Near Palm Beach 55' andreavanduyn Monohull Sailboats 0 21-08-2009 10:23
Sailboat Transport MatildaMouse Dollars & Cents 14 11-08-2009 23:00



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 13:59.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.