Re: Weighing a boat with bathroom scales
Posted: Tue Nov 01, 2016 5:43 pm
Hi Mike and Steamboating colleagues
Thank you so much for the suggestions so far. I have been contemplating Mike's proposal this afternoon (only found that folk had answered the post at lunch time) and wonder if I should add some information and some thoughts.
As the boat is in the garage which has a gravity leveled concrete floor we have a nice level platform on which to work. The trolley is a wooden frame that has three significant cross members in the centre of each is a nylon roller that is proud of the cross member by about 1/4" (Measurement mistake on my part during construction). The boat has two bilge keels that are arranged so that they are at the same level as the keel over part of their length. Thus if placed on a flat surface she would sit horizontally level which is what happens on the trolley. At the rear of the trolley is a V cradle on the cross member which ensures that the boat stays level if the bow is raised thus removing the support of the bilge keels. There is also a V cradle on a 'loose' cross member slotted into the trolley frame at the front. This is the 'string' bit of Belt, Braces and String.
If one had (say) some two inch square section steel tube, it would be possible to slide this under the boat but over the longitudinal frame of the trolley. Taken at a point as far as possible forward where the bilge keels and keel are in line crossways the risk of tipping would be zero. There would be no problem building up supports from my stock of 8 X 2 offcuts and other stuff and that could be topped by a bit of 2" angle iron to give a 'pivot' point from which to measure. As the boat is on one side of the garage the bar could project out into the body of the garage allowing plenty of space for the positioning of the scale. Given that the stern hangs a fair way off the trolley and is or can be lined up with the door into the garden, there is scope for doing a second weighing with the bar at that point. I would imagine that in all cases the boat would not be lifted by more than an inch or so. For additional safety it would be possible to use the engine hoist gantry that sits over the boat to support a safety sling.
Since I have CAD drawings of the cradle and the boat kicking around somewhere I will try bringing them together and show what I was thinking.
Regards
Pete
Thank you so much for the suggestions so far. I have been contemplating Mike's proposal this afternoon (only found that folk had answered the post at lunch time) and wonder if I should add some information and some thoughts.
As the boat is in the garage which has a gravity leveled concrete floor we have a nice level platform on which to work. The trolley is a wooden frame that has three significant cross members in the centre of each is a nylon roller that is proud of the cross member by about 1/4" (Measurement mistake on my part during construction). The boat has two bilge keels that are arranged so that they are at the same level as the keel over part of their length. Thus if placed on a flat surface she would sit horizontally level which is what happens on the trolley. At the rear of the trolley is a V cradle on the cross member which ensures that the boat stays level if the bow is raised thus removing the support of the bilge keels. There is also a V cradle on a 'loose' cross member slotted into the trolley frame at the front. This is the 'string' bit of Belt, Braces and String.
If one had (say) some two inch square section steel tube, it would be possible to slide this under the boat but over the longitudinal frame of the trolley. Taken at a point as far as possible forward where the bilge keels and keel are in line crossways the risk of tipping would be zero. There would be no problem building up supports from my stock of 8 X 2 offcuts and other stuff and that could be topped by a bit of 2" angle iron to give a 'pivot' point from which to measure. As the boat is on one side of the garage the bar could project out into the body of the garage allowing plenty of space for the positioning of the scale. Given that the stern hangs a fair way off the trolley and is or can be lined up with the door into the garden, there is scope for doing a second weighing with the bar at that point. I would imagine that in all cases the boat would not be lifted by more than an inch or so. For additional safety it would be possible to use the engine hoist gantry that sits over the boat to support a safety sling.
Since I have CAD drawings of the cradle and the boat kicking around somewhere I will try bringing them together and show what I was thinking.
Regards
Pete