A 27 balsa cored hull

[sail149]

So I saw a listing for an A27 suggesting the A27 hulls were solid fiberglass. I advised the broker that was incorrect.
The broker sent me something that suggested the RI boats were solid. The A27's were made in Wallingford and cos cob CT. The 28 and onward were made in RI " c&c marine ( the old Pearson plant I think). They were all balsa cored hulls later changed to partial Airex foam about 2000.
So as I research additional information from the Albin brochures they suggest the fiberglass lay up and the balsa coring for the 8' alongside the skeg. So maybe solid under the engine and FWD. Which would be nice. My transducer at the midpoint of the engine is in balsa coring though.
The layup suggested is rather optimistic I think though. Or my boat was built on a Monday as the hull at the 'garboard' drain is barely 1/8 thick.
The 6 layers of 1815 fab mat should be over 3/8" ( the 18 part should be 1/8/ layer the 15 part should be about 1/16/ layer).
Below are the sections from the brochures

The stainless steel back plates are interesting fiction.
To be fair the early boats may have had some or all of this construction, but of course the out is that production changes , bla,bla etc. but GM do exactly the same thing , hi spec on first year of production ( the ones that get reviewed) then spent the rest of the production run figuring out what they can leave of, or replace with a cheaper alternative!

[JT48348]

FYI: have a research project going. I will posting some information soon that indicates the A27 hulls were solid fiberglass approximately 3/8", no information like you have above but good to know. This includes the first 10-15 boats and all later boats into the 80s contracted to be built by Fred Peters Albin Marine.

I wonder if they are referring to reinforcing the aft flat sections, either side of the siege by adding balsa for rigidity then glassing over it. When I think balsa coring I think thin fiberglass skin sandwiching balsa. This sounds like a reinforcement from the interior.

I can confirm the stainless backing plates bedded in the deck glass for the forward bow pulpit and aft stern rail. I have a 1986 boat I think I'm either #305 or #515. I posted this during my bathroom renovation. When I removed the headliner there were no exposed nuts for through bolting of deck fittings. Nuts and backing plates were glassed in and I had to grind into the glass to and then cut off the nuts to get the bow and stern rail off. There are indeed small stainless or alum backing plates embedded in the glass. They are too small in my opinion, roughly the same size as the deck fittings.

[Sprig1]

I had the small backing plates on mine as well when I took off the bow pulpit. I didn't have to grind anything I used a sharp chisel to chip the fiberglass then a dewalt impact driver all the nuts came off. I haven't pulled the bow pulpit yet just have it loose. I can't wait to see the rot under them. Jt did you take out the backing plates are you installing new ones ? I have taken out the thru the hull was cored there.

[JT48348]

Surprisingly I didn't have much rot either in the deck or below. But the chance for leaks is too great in a 30 year old boat. They appeared to have been bedded with butyl or something.

I'll be using new backing plates or blocks. I have lifelines and stanchions too so everything needs good bases. On my recent sailboat project I used 1/2" coosa board scraps with one side having a layer of fiberglass. It's awesome. But it would raise the profile for the A27 headliner/ceiling. I may use that or go with actual wider plates.

The coosa would be easier. I would mix up thickened epoxy and attach. Then re-drill holes according to ones in deck ( which I filled) then mount hardware. I think ultimately this is what I'll do.

[sail149]

JT , I would be extremely suprised if any of the A27's did not have balsa coring in the aft flat section as described above. I think we are solid in the engine area though.
It was and is very common practice to core hulls to stiffen the structure without having to add extensive frames or ribs. I know my boat had the balsa replaced in the aft sections, the yard owner told me as I dragged it out of his yard! They were very experienced fiberglass repair folks though.
All the more modern Albins built in RI , 28's and onward all had balsa coring until they changed to a PVC AIREX foam about 1990 time frame supplied from Baltek , the balsa suppliers. They continued to use balsa in other areas including the decks and sides of the hull.
This make interesting reading if you are into this sort of thing
http://www.craigmarine.info/yacht_boat/ ... /albin.htm
A cored structure in fiberglass is really the way boats are made. Solid fiberglass goes back to a much earlier era, 60's.
The cape dory 28's claim they are solid hulls , I would like a chance to poke about in the builges of one to be sure.
Plywood was a common core material espically in the decks,really a poor choice unless the right plywood was used as it is prawn to a lot of rot and does not have very good compression strength.
When I was building hi end power boats in the 80's we used a lot of balsa in the hull sides, and deck, we had a conservative company owner who insisted on a solid running bottom for the boats so we had to build an extensive 'Egg crate' structure in the entire bottom of the boat where there was no panel over about 12-18" without structure.
After the hull skin was made it took a week for a team of about 8 mainly woman to install the marine plywood ribs and apply layers of fiberglass all over to completely encapsulate the wood work and then grind smooth and coat with gel oat on the inside.
That was a Hugh amount of work for a 40+ boat. Similiar size boat hulls were being built down the road in a 2 shift per day factory at the rate of one hull a day! Using a cored hull of course.
Coring done well , and methods improved as time went on, is a really good way to go. But like everything else it has to be done right. I have my doubts about the long term durability of the ' egg crate' boats with all that encapsulated wood but there was a lot of care taken ( hence the use of woman) to do a really good meticulous job and I hear they hold up very well. But they are not out these in the numbers of come manufacturers.
Sorry if this I little of Albins....

[JT48348]

Here's a photo of one of the aluminum backing plates embedded in the fiberglass if the aft cabin for one of the stern cleats. Fell on my head while grinding to prep the aft cabin for paint and new headliner panels.


It's approximately 1" wide by 2" long, 1/8" thick. On a four hole deck clear this was one side of the cleat only.

[Beta Don]

My boat had teak backing plates under the nuts for the cleats and the bow pulpit - No metal of any kind embedded in the glass. Another difference between early and late models I guess

Don

[sail149]

So I stand corrected , my pulpit does have SS backing plates.

image.jpeg

However the stern pulpit is different
There I have small aluminium plates with fiberglass mush on top to continue the liner stapling surface/wood.
You can see it under the cracked mush when I removed the pushpit bolts.
The corrosion of the aluminium is excessive.

And Here is what I am doing to replace cleats that were added later thru the liner!

[JT48348]

Under the headliner, both forward cabin and aft, is a wood piece approx 1/2" thick and 2-3" wide that rings each cabin on the underside of the elbow. Where there are deck fittings, the board was cut out and the metal embedded then glasses over with solid fiberglass filler. The wood piece butts up against the hull deck joint and it's attached with stainless screws into the underside of the deck. The purpose of the wood is to give something for the headliner to be stapled or glued to.

It's nasty work to remove it.

[rnummi]

I can only imagine..... I keep looking up there knowing those holes are lurking. My guess is the forward handholds (if consistent with the rest of my boat) don't have bedding. Which of course means it's been leaking onto inside of headliner, trickling down to the wood. It's like having a monster in your closet. You know it's there, you just don't want to look. Based on your observations, You think they mounted headliner to underside of deck at factory before joining the deck to hull?

[JT48348]

No.

Hull to deck & pan liner assembled then boat fitted out with systems.
Then headliner & finish

[rnummi]

Thanks.

[JT48348]

Just removed the above waterline thru hulls. Here are some photos of the hull thickness. Midship at the engine compartment, hull is measuring approximately 3/8" thick solid fiberglass. Aft and fwd cabin appeare slightly less but not by much. Solid and bonded well.

All my above waterline thruhulls were nylon or a poly plastic. There are a lot of holes in the boat above the waterline primarily because the cockpit scuppers drain into 4 thru hulls at various places. In removing hoses several cracked or sheared off so you will want to check these if you're doing any work.

[JT48348]

I have only 3 below waterline thruhulls all bronze. These appear original. If you look at the engine compartment hull there appeares a built up area where these go thru hull. Instead of a backing plate it looks like the hull was beefed up to accept the fitting. I have no softness so am debating pulling them as they open & close fine.

[JT48348]

Removed the side side air vents.

Here you can see delamination of the hull skin around only one vent. This appeared due to either overhead leak from deck fitting or more like hull deck joint. I think I'm going to pull rib rail just check and see, since the is the only location where I saw delamination. Otherwise was impressed with hull. It's not as thick as my my 1972 classic sailboat ( nothing is) but hull is solid and no sign of coring except for transom.