Joining the hulls, Levelling the hulls

Groundhog day.

Posted by Paul

After 2 days in Melbourne I was keen to get some work done on the boat today. In the afternoon I decided to tackle the second hull level. To do so I had to start the port hull again from scratch. I removed the wedges I had put in to raise the hull to the height of the starboard one, but had got me into the hamster wheel of raising and lowering each end of the hull.

Although it is not wise to measure from the floor unless you are absolutely sure it is perfectly level, I decided it was a good starting point, so I measured from the floor to the waterline mark at the bows and made the port hull measure the same from the floor as the starboard, remembering that the starboard hull is level and higher than the port hull). I then put legs onto the bows to ensure the bows could not drop lower than this. The port hull could (and did!) still lift but with the leg screwed on I would not have to measure to see it had, I would instantly see that the leg was raised off the ground so therefore the bow had lifted.

I then measured from the ground to top edge of the stern at centreline as the waterline is not as easy to find with the shape of the stern and the antifoul on and then lowered the port hull to the same height as the starboard hull. To raise or lower the hull is really simple, you can simply move the cradles backwards or forwards and to move them easily I have a pallet jack that I use to raise the hull then move the cradle and lower the pallet jack again. Once I had the bow and stern the same I then used the water levels to check the heights and found that I had to raise the hull about 10mm at the stern to get the WL1200 at the stern to match the bow. Once I had done that I checked it against the starboard hull and found it was level at the WL1200 at the CL1500 marks on the bulkhead returns. So far so good.

I then found that because I had raised the stern, the bow was also raised (the leg was off the floor) so I lowered the bow the 10mm and rechecked CL level at WL1200, level again, and I re measured the distance from the ground to the stern and it was 5mm higher than the starboard hull but the water level showed it as level so I am willing to ignore this 5mm discrepancy as more likely due to the floor being out.

I decided to re check level of starboard hull at CL and this was still fine, so I checked from starboard stern to port bow at CL at WL1200 and I yelled out in frustration that it was a whopping 100mm out! I couldn’t believe it. I was about to give up for the day when I realized that in order to measure at the centreline on the rear bulkhead you have to clamp a crossbeam to the bulkhead to the WL1200 line as the bulkhead is cut away, which I did, but I was levelling to the top of the crossbeam not the bottom, so effectively 100mm higher than WL1200 or WL1300 if you like! To see what I mean take a look at the picture above here and you will see that the bottom of the clamped on piece is level with the WL1200 mark. Bingo, there is my 100mm discrepancy and once I measured to the correct mark my hulls were level. Finally.

Because I am anal, tomorrow I will recheck the levels using the water level against different marks and points on the hulls at CL and CL1500 and at WL and WL1200 across the hulls from corner to corner, directly across from one hull to the other at the same bulkhead and along the same hull at CL and CL1500. After about an hour or so of this I will finally accept that the hull is absolutely level and ready to join. I may even get to join one of the bulkheads!

You May Also Like