Stability of Flybridge question with new Hydraulic Swim Platform

[mgernes]

After years of trying to improve my current crane mechanism on our 1973 53my, including rebuilding the crane itself, adding a pulley system to move my Amanzi tender( a Mercury Product) on and off the chalks on the top of the flybridge, I have finally decided to have Florida Bow-Thrusters replace my existing swim platform with a hydraulic lift. Granted, the Amanzi is slightly heavier than the original whaler that came with the boat, but full of gas, it still weighted less than 700 pounds.

I have boated all my life, and very little rattles me, but there are few parts of my boating experience that I dislike more than lowering, then later lifting my tender. Over the 15 years that I have owned Beach House, I have spent more time and energy trying to perfect this process. My cable has been stuck in the pulley twice, the original crane that came with the boat broke at least once even after I re-inforced it. It has almost become a spectacle sport whenever I launch or retrieve my tender. Then add some wind and waves, with the tender bouncing off the starboard side of the boat... Did I mention the one time when the cable broke and it came flying back at me?

Granted, some of these issues might have been operator error early on as I was learning my way, but over time I expected that I would become more competent with this process, but to this day, I still wince when I prepare to lower or raise my tender.

As a by-procuct of this change, I am planning to enlarge the usable space on the flybridge where the tender had been, which brings me to the meat of my post.

Yesterday when I visited our Marina shop where the work is being completed, I was up on the flybridge, standing where the tender had been, and when I tested the stability near the aft section of the flybridge, I noticed the stainless steal supports for the flybridge, which come off the handrails on the aft-deck were slightly buckling. The handrails also had movement. Not failing or tearing out of the area where they attach to the handrail, but enough movement that I am concerned about what might happen when a few more people are up there.

I have already had our shop thru-bold the supports where the stainless steal rails come in contact with the ceiling of the aft deck, and later today they are going to thru-bolt where the stanchion from the floor of my aft deck comes in contact with the bottom of the handrail. If that does not give me the support I need, I may have to add some additional 45 degree supports to the lower stanchions on the afterdeck, or add vertical supports from the floor of my afterdeck to the ceiling.(this would be my last choice since it would add clutter to my aft deck).

One theory I have as to why we have never noticed this weakness before, whenever I move my tender around, is that the boat was in the water, not on a cement floor, and the water acted as somewhat of a shock absorber. This is just my theory, but there is always someone in my afterdeck whenever I retrieved my tender, and I can't imagine they would not have noticed how much flex was showing in the supports when I set the tender down on the chalks.

Bottom line-I am looking for feedback about the strength of the aft section of the flybridge floor, and any suggestions that I have not thought of to improve stability.

Marcus Gernes
Beach House

[SEVEN]

After years of trying to improve my current crane mechanism on our 1973 53my, including rebuilding the crane itself, adding a pulley system to move my Amanzi tender( a Mercury Product) on and off the chalks on the top of the flybridge, I have finally decided to have Florida Bow-Thrusters replace my existing swim platform with a hydraulic lift. Granted, the Amanzi is slightly heavier than the original whaler that came with the boat, but full of gas, it still weighted less than 700 pounds.

I have boated all my life, and very little rattles me, but there are few parts of my boating experience that I dislike more than lowering, then later lifting my tender. Over the 15 years that I have owned Beach House, I have spent more time and energy trying to perfect this process. My cable has been stuck in the pulley twice, the original crane that came with the boat broke at least once even after I re-inforced it. It has almost become a spectacle sport whenever I launch or retrieve my tender. Then add some wind and waves, with the tender bouncing off the starboard side of the boat... Did I mention the one time when the cable broke and it came flying back at me?

Granted, some of these issues might have been operator error early on as I was learning my way, but over time I expected that I would become more competent with this process, but to this day, I still wince when I prepare to lower or raise my tender.

As a by-procuct of this change, I am planning to enlarge the usable space on the flybridge where the tender had been, which brings me to the meat of my post.

Yesterday when I visited our Marina shop where the work is being completed, I was up on the flybridge, standing where the tender had been, and when I tested the stability near the aft section of the flybridge, I noticed the stainless steal supports for the flybridge, which come off the handrails on the aft-deck were slightly buckling. The handrails also had movement. Not failing or tearing out of the area where they attach to the handrail, but enough movement that I am concerned about what might happen when a few more people are up there.

I have already had our shop thru-bold the supports where the stainless steal rails come in contact with the ceiling of the aft deck, and later today they are going to thru-bolt where the stanchion from the floor of my aft deck comes in contact with the bottom of the handrail. If that does not give me the support I need, I may have to add some additional 45 degree supports to the lower stanchions on the afterdeck, or add vertical supports from the floor of my afterdeck to the ceiling.(this would be my last choice since it would add clutter to my aft deck).

One theory I have as to why we have never noticed this weakness before, whenever I move my tender around, is that the boat was in the water, not on a cement floor, and the water acted as somewhat of a shock absorber. This is just my theory, but there is always someone in my afterdeck whenever I retrieved my tender, and I can't imagine they would not have noticed how much flex was showing in the supports when I set the tender down on the chalks.

Bottom line-I am looking for feedback about the strength of the aft section of the flybridge floor, and any suggestions that I have not thought of to improve stability.

Marcus Gernes
Beach House

Sent you a PM

[doc g]

most of the crane manufacturers will tell you do not use the lift when the (big) boat is out of the water due to the stresses it will produce..............Pat

[Toolsntoys]

On my boat there is 4 supports that go from the lower deck to the roof deck. The hand railing is tied into the supports. I’ve seen on other makes that there is simply two vertical posts. On each corner. Personally I don’t like the idea of putting a 700lb dingy on the flybridge. A small lightweight inflatable sure but those are only 250 with a ten hours motor

[SEVEN]

And some of the 1979 models they added two, 2 inch support beams halfway back on each side. When I get to the boat this weekend I’ll take a photograph and send them to you.

[Pascal]

Having extensively used both top deck davits and hydraulic platforms I much prefer using a davit especially when chop or surge has built up. Lining up a tender on the platform with just little wave/surge is scary and it s a lot easier to control the tender if it swings on the davit than on a slippery platform

The key to easily launch and retrieve a tender is to have a line permanently rigged bow to stern on the tender. The line need to be about twice the tender Length and need to have a small loop in the middle. Next you rig a line from the boat decks long enough to reach the water witha carabiner at the end. Before retrieving you clip that line in the loop on the tender line. This allows to control the load from the top deck. No need for help.

As to your support question my ealier 53 has a pair of 3” alum poles on each side which provides plenty of support. Soon after that Hatteras went to thinner tubes attached to the stern railing. I guess it works but but the angle isn’t ideal since the hard top is much shorter than the deck. Any load on the top deck may push the railing back unless everything is thru bolted and tight.

[SEVEN]

After years of trying to improve my current crane mechanism on our 1973 53my, including rebuilding the crane itself, adding a pulley system to move my Amanzi tender( a Mercury Product) on and off the chalks on the top of the flybridge, I have finally decided to have Florida Bow-Thrusters replace my existing swim platform with a hydraulic lift. Granted, the Amanzi is slightly heavier than the original whaler that came with the boat, but full of gas, it still weighted less than 700 pounds.

I have boated all my life, and very little rattles me, but there are few parts of my boating experience that I dislike more than lowering, then later lifting my tender. Over the 15 years that I have owned Beach House, I have spent more time and energy trying to perfect this process. My cable has been stuck in the pulley twice, the original crane that came with the boat broke at least once even after I re-inforced it. It has almost become a spectacle sport whenever I launch or retrieve my tender. Then add some wind and waves, with the tender bouncing off the starboard side of the boat... Did I mention the one time when the cable broke and it came flying back at me?

Granted, some of these issues might have been operator error early on as I was learning my way, but over time I expected that I would become more competent with this process, but to this day, I still wince when I prepare to lower or raise my tender.

As a by-procuct of this change, I am planning to enlarge the usable space on the flybridge where the tender had been, which brings me to the meat of my post.

Yesterday when I visited our Marina shop where the work is being completed, I was up on the flybridge, standing where the tender had been, and when I tested the stability near the aft section of the flybridge, I noticed the stainless steal supports for the flybridge, which come off the handrails on the aft-deck were slightly buckling. The handrails also had movement. Not failing or tearing out of the area where they attach to the handrail, but enough movement that I am concerned about what might happen when a few more people are up there.

I have already had our shop thru-bold the supports where the stainless steal rails come in contact with the ceiling of the aft deck, and later today they are going to thru-bolt where the stanchion from the floor of my aft deck comes in contact with the bottom of the handrail. If that does not give me the support I need, I may have to add some additional 45 degree supports to the lower stanchions on the afterdeck, or add vertical supports from the floor of my afterdeck to the ceiling.(this would be my last choice since it would add clutter to my aft deck).

One theory I have as to why we have never noticed this weakness before, whenever I move my tender around, is that the boat was in the water, not on a cement floor, and the water acted as somewhat of a shock absorber. This is just my theory, but there is always someone in my afterdeck whenever I retrieved my tender, and I can't imagine they would not have noticed how much flex was showing in the supports when I set the tender down on the chalks.

Bottom line-I am looking for feedback about the strength of the aft section of the flybridge floor, and any suggestions that I have not thought of to improve stability.

Marcus Gernes
Beach House

Here are the photos I promised. These came standard on some 1979 and 1980’s. Not all but some. They are all exactly alike so I know they were standard.

[mgernes]

I appreciate all your feedback, and the pictures are a great help!!

Much appreciated,

Marcus

Beach House
Hull#421

[captainwjm]

[QUOTE=Pascal;341960The key to easily launch and retrieve a tender is to have a line permanently rigged bow to stern on the tender. The line need to be about twice the tender Length and need to have a small loop in the middle. Next you rig a line from the boat decks long enough to reach the water witha carabiner at the end. Before retrieving you clip that line in the loop on the tender line. This allows to control the load from the top deck. No need for help[/QUOTE]

I’m interested in seeing more about this technique. Is this to minimize swinging away from the mothership only, or does it also address the bow/stern yaw of the tender?

[Pascal]

Both. You get full control of the tender by limiting swing and keeping it lined up. And because you lift the line from the top there is no need for a helper downstairs and no trying to throw lines upstairs Been doing it that way for years and sometimes i launch and retrieve tender or jet ski twice a day on charter.