Mac 21 flotation

[Seán]

Hi,I just purchased an '86 Mac 21 which has made it's way to the west of Ireland. The guys who had it had removed some of the flotation blocks because it was crumbling and making a mess. There are still two large intact blocks under the cockpit. I'd like to replace the forward flotation with polyurethane expanding foam under the v berth. Does this sound like enough? Alternatives?

 

[John Dawson]

Mac flotation

Hello Sean, my family comes from Mayo, Maryland just south of Annapolis. We got our '77 Mac-22 in 1990, and the flotation consisted of the large blocks under the cockpit and as many as would fit under the vee berths. There may have been a few small blocks under the seats inside, but thats about it apart from the bunch of spare life vests stowed below. I don't plan on putting it to the test any time soon. Seems like this wouldn't be enough to float the keel, motor, and hull too, but I'm sure someone has the facts on it. Would have to compare the boats weight to that of the displaced water, I suppose. Displacement is 1175 lbs.The original brochure can be found thru the links at the bottom of this site, looking for the New England MacGregors group. It mentions 'positive flotation' provisions, but that may just mean added styrofoam. I will try to put the direct link on this article.

 

[John Dawson]

Mac-21 floatation

Sorry, link was for v-17, but you may have found your way over to the v-21 brochure anyway. Here is the link for the v-21. Displacement 1200 lbs.

 

[Seán]

Thanks

Cheers John,The manual also says you shouldn't remove any of the blocks, which is what the previous owners did. I'll try and calculate the displacement numbers.