I am working on my recently inherited mac 25, and I cant help but wonder why there is no mast post? Since I looked for an hour to see what this thing is called, I will clarify: I am refering to the support post in the cabin for a deck stepped mast that provides support and load transfer from the bottom of the mast to the keel. (I have seen this called Jack Post or Sampson Post on the net) I have considerd adding one as the current condition of the deck at the mast base plate looks like bad. Since I cant seem to find any pictures of anyone doing this, I must assume there is a good reason why 'jack posts' are not needed? Also, if anyone has done this how did you connect to the keel assembly? Any insight would be greatly appreciated! Thanks! Cdog
Why not a Mac25 Mast Post/ Jack Post ?
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Really?
Your kidding?
Yes, there should be a compression post, has to be. The load from the mast and shrouds will colapse the deck! Is there an inclosed head? A closet between the vee berth and the keel trunk? There should be a 2x4 size board standing at the center aft corner of the head. It has a small angle bracket bolted through the post, and a small bolt up through the deck behind the mast. There is no bracket at the bottom of the post, the aft bulk head is screwed into the post to hold it in place and the bulk head is bolted to a bracket which is bolted to the starboard side of the hull/liner. If there is no compression post, there must also be no head or closet?
Yes, there should be a compression post, has to be. The load from the mast and shrouds will colapse the deck! Is there an inclosed head? A closet between the vee berth and the keel trunk? There should be a 2x4 size board standing at the center aft corner of the head. It has a small angle bracket bolted through the post, and a small bolt up through the deck behind the mast. There is no bracket at the bottom of the post, the aft bulk head is screwed into the post to hold it in place and the bulk head is bolted to a bracket which is bolted to the starboard side of the hull/liner. If there is no compression post, there must also be no head or closet?
let me clarify
First, I want to thank you for your reply. I looked at my original message, and appologize for a few items I left out. For clarification: 1. there is no head 2. there is no closet between the vberth and keel. 3. there is the 2x4 post connected as you described to the deck, and connected to the only partition wall which starboard and seperates the dining seating from the forward part of the boat. This partion was connected as you described to the starboard hull. The bolt that goes thru the deck and is connected to the angle on the top of the mast post is what seems to be causing all the cracking problems on the deck. It looks like a bad stress point on the deck caused by this connection. Furthermore....since the post, as you mention, does not have ANY bottom connections, I assumed this was not transfering MAST loads directly to the hull, but was acting more like a shim to support the deck above. THUS my orignal question assumed that this 2x4 post was not a real mast post. If the normal/standard mac25 mast support is as you described above, it appears that the mast loads are not really transfered directly on this 2x4 post, but rather, most of the mast load transfer to the hull thru the plywood partition connected to the starbord hull. With all that clarified and understood....this seems like a weak connection/transfer of loads! And from the looks of fiberglass cracks at the mast base plate, it seems like it is not working! This is how I see it: When I raise the mast, I know there is only a dinky 2x4 below the mast...which has no solid connection at the bottom to the keel (so what does it really doing?), and the post is not really connected directly to the mast base plate, but just one little screw to thru the deck, AND finally, the dimensions of the post is smaller than the mast above (shouldn't this mast post be the same size or larger than the mast above?). I guess my question really should be...has anyone out there modified a macgregor 25 mast post in a better way than the original design? I hope to create a new mast post which connects thru the deck directly to the mast base plate and at the bottom to the keel. The keel connection obviously seems the most difficult due to the swing keel and all that stuff. Thanks for your time and help! Cdog
First, I want to thank you for your reply. I looked at my original message, and appologize for a few items I left out. For clarification: 1. there is no head 2. there is no closet between the vberth and keel. 3. there is the 2x4 post connected as you described to the deck, and connected to the only partition wall which starboard and seperates the dining seating from the forward part of the boat. This partion was connected as you described to the starboard hull. The bolt that goes thru the deck and is connected to the angle on the top of the mast post is what seems to be causing all the cracking problems on the deck. It looks like a bad stress point on the deck caused by this connection. Furthermore....since the post, as you mention, does not have ANY bottom connections, I assumed this was not transfering MAST loads directly to the hull, but was acting more like a shim to support the deck above. THUS my orignal question assumed that this 2x4 post was not a real mast post. If the normal/standard mac25 mast support is as you described above, it appears that the mast loads are not really transfered directly on this 2x4 post, but rather, most of the mast load transfer to the hull thru the plywood partition connected to the starbord hull. With all that clarified and understood....this seems like a weak connection/transfer of loads! And from the looks of fiberglass cracks at the mast base plate, it seems like it is not working! This is how I see it: When I raise the mast, I know there is only a dinky 2x4 below the mast...which has no solid connection at the bottom to the keel (so what does it really doing?), and the post is not really connected directly to the mast base plate, but just one little screw to thru the deck, AND finally, the dimensions of the post is smaller than the mast above (shouldn't this mast post be the same size or larger than the mast above?). I guess my question really should be...has anyone out there modified a macgregor 25 mast post in a better way than the original design? I hope to create a new mast post which connects thru the deck directly to the mast base plate and at the bottom to the keel. The keel connection obviously seems the most difficult due to the swing keel and all that stuff. Thanks for your time and help! Cdog
Jack Post
The compression post must stay within the cabin. It cannot pentrate the cabin roof or you'll weaken the deck and allow (more) water to leak in. If the deck is weak under the mast, you need to fill it with epoxy. See compression post in manual and brochure for the 25 here: http://www.macgregor-boats.com/ Happy sails *_/), MArk
The compression post must stay within the cabin. It cannot pentrate the cabin roof or you'll weaken the deck and allow (more) water to leak in. If the deck is weak under the mast, you need to fill it with epoxy. See compression post in manual and brochure for the 25 here: http://www.macgregor-boats.com/ Happy sails *_/), MArk
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