Removing forward head compartment bulkhead

[Ixneigh]

I agree with all of this. These are not 6000 lb keelboats made in the 70’s where you might get away with taking a structural member out.
However there’s no going back, so now I need to figure out the best way to replace the bulkhead. The stainless tube frame is one option, expensive and might be tricky to fit. (Would need to be two pieces bolted together)
I can make a mostly fiberglass 2x4 deck beam and tie that into the inside of the hull (also useful as a base for much needed storage bins up there)
I could also restore the lost torsion and bowing by adding thickness to the hull on both sides from about a foot back from the bow, to even with the mast. These panels I’m guessing would need to be about two feet wide and 3/8 thick. I may be able to use Coremat for that, but I’d have to consult my local fiberglass expert. I’m set up to do glass work, and that option would be easiest for me.

Ix

[OverEasy]

Hi Ixneigh!

While I can’t tell you what specifically to go back with…that’s gonna be your call (for a host of reasons beginning with the aspect of I don’t have a Mac26M and you know what you have available to work with)… I can suggest a process of how you might go about evaluating what you might want to do ….

Look at where the mast is located relative to where the removed bulkhead was.
There is gonna be a relatively significant downward force associated with that region that you are going to need to support from ceiling to the keel line. (Remember all the mast stays exert a considerable compressive load to the top deck in a relatively concentrated area…both statically and dynamically).

Then there are the deck live loads due to people’s movement on the top deck.

With the mast down I’d suggest starting with the assumption of a 300-to-500 pound load concentrated on an area of about a square foot on either side of the mast to simulate to hefty adults standing on either side of the mast.
I’d rig up a means to measure the amount of deck downward deflection. A rigid post that is a couple of inches short of the inner liner and a tape measure should suffice.
Gradually apply the deck load… I would not recommend applying it all at once.
See what the downward deflection is… Hopefully it is minimal…

Then with the mast being raised and secured repeat the deflection measurement.
Again, Hopefully it is minimal…

Then gradually add on the live loads again and see what the deflection measurement is.
Again, Hopefully it is minimal…

I would expect deflection of less than a 1/2 inch…smaller is better.

Next is look at the mast torsional side-to-side bending at the base of the mast.
The Mac26M has a swiveling mast so I really am not familiar with how that interface works…but the good news is that the mast stays take on most of that type of loading and transfer it to the stays chain plates. Similarly with the fore and aft stays.

At this point a good pint or is in order for you and your participants.
You’ve all earned it!

If your deflection measurements are all minimal then you are probably Golden!

There still remains the hull side deflection aspects and hull bow but I’ll be darned if I can think of a reasonable way that one could check those without some complicated fixturing.

Anyway, that’s a means to verify if there is actually an issue with the removal of that bulkhead…and it only a suggestion…not a definitive answer. I figure it might be easier and less costly to check and verify whether or not you have deflection before attempting to make a reinforcement that might not be needed, or worse, inadequate.

Best Regards
Over Easy

[Jimmyt]

Consider making a bulkhead perimeter laminate using a few layers of 3/4 plywood. Resin/glass the whole business together and buy some longer bolts and bolt it in place of the bulkhead you removed. 4” width around the perimeter would probably be wide enough if you made it strong.

That way, you still have the rigidity - without having the majority of the bulkhead in the cabin. Basically, it’s just a big “C” shape…

[OverEasy]

Ditto on JimmyT’s suggestion (if something is needed)…
Though I suggest that the ‘inside’ corners of the “C” have a really generous radius (6+ inches) and router the inside edges…makes the fiberglass wrap easier and the radius feels better when you run into it (been there/done than )

[NiceAft]

Ix,

Compared to what it seems you need to do, will the end result be worth it

You have too much time on your hands. Get a part time job.

[OverEasy]

Aren’t our owning a MacGregor our part time jobs?…..

[NiceAft]

In 2004, when we purchased our 2005 , the Admiral and I made a pact; the boat would not dictate our lives. To us, it was a toy to be enjoyed. It has been this way for over eighteen years. The boat lives for us, not the other way around.

As my friend Highlander would state; “Just saying”.

[Jimmyt]

Not putting words in OverEasy’s mouth, but some of us love boat projects. As they say, “if you love what you do, you’ll never work a day in your life”. So, our part time job is a labor of love.

But, I certainly understand the concept of using the boat for boating enjoyment only. YBYR.

[NiceAft]

Not putting words in OverEasy’s mouth, but some of us love boat projects. As they say, “if you love what you do, you’ll never work a day in your life”. So, our part time job is a labor of love.

But, I certainly understand the concept of using the boat for boating enjoyment only. YBYR.

Couldn’t agree more. Just speaking up for those that just play. We wouldn’t want them to feel guilty would we.

[Jimmyt]

Couldn’t agree more. Just speaking up for those that just play. We wouldn’t want them to feel guilty would we.

Nope! You and I are all about celebrating diversity!

[NiceAft]

You say YBYR. I say the 3 S.W. rule.
Some Will, Some Won't, So What

[Ixneigh]

Re: “C style” frame. This is what I’m leaning towards.
Re: get a part time job, I spend half the year on the boat, so it’s worth it to me to make changes that improve it for my particular use. I had the boat long enough now to contemplate major changes based on what does or does get used.
Re: Get a different boat. No other boat has as cool a web forum but honestly, I’ve seen few I’d want to switch to that are within my price range.

Ix