Full Keel Bilge Structure Question!

[wesley Sherman]

I am rebuilding a Alberg 30 complete gut and am putting it back together now... I have been looking at the bilge for a while now and there is only two very thin 3/4 plywood thinly fiberglassed in. One just under the engine pan and one in couple feet further forward.
My question is what is the job of the stringers crossing attaching the hulls together. There is some sort of structures blending here it would seem. I can't find anything on the internet in my searches to explain it.. I can assume its to bind the gap between the hull to stiffen and bind it together. These are the only two there about 2 feet apart.





The two stringers that are in here cant be seen in this second picture.. There is no more stringers in the areas shown.

So what i want to figure out and ask question to you all more knowledgeable people is..
How many stringers across the bilge gap should be reasonable and how thick should they be, 2" less more.. and how many. I am about to tear them out and start the cleaning to repair rebuild this area.. I feel like there should at least be three.

thank you for your input and help..

 

[bajansailor]

Terminology can be confusing - I think that what you are calling 'stringers' are usually referred to as 'floors' (which in itself is confusing, as these would then typically support the cabin sole, or 'floor' in house speak).
Stringers normally refer to the longitudinal stiffeners in the hull.
I think you have to bear in mind that your hull is probably 50 (?) years old now, and it would have been massively constructed (relatively) when fibreglass was still a relatively new and unknown material. And it seems to have survived ok.
Maybe just replace the two existing transverse floors if you really have to - what condition are they in?

 

[wesley Sherman]

They're not in great condition, and you're right they're called floors. The wood is extremely dry and the fiberglass tabs are delaminating. They are crying and begging to be redone. I will be cutting and pulling them out this coming week and will start the cleaning and what not to reinstall fresh new ply. If putting them back the same I will probably then add two more along the length the same way it was done before, and I say two more so that the floor will be supported with (Floors) lol. Where there is no floors it is supported by massive amounts of polyester and what looks like wood fiber slopped in to make a support. to hold the floor up.

I am pretty much replacing / upgrading everything back to better than before, because in the next 20 years this boat will see enough sea to make it seasick and groan every time I step aboard. And other than maintenance and the unexpected expected events I don't want to do anything major.

 

[kapnD]

If the boat has survived this long with those minimal bulkheads so lightly tabbed in, it would probably survive without any at all!
However, if it were mine, I’d reinforce the hell out of it, making sure that reinforcement was continuous from as deep in the bilge as practical to clear up under and fastened to the deck.

 

[wesley Sherman]

I tend to agree with kapnD, I have started the removal of the bilge structures. There is a second layer of ply almost 20 below the sole, I haven't removed this, however I sorta want to to see what is under that. Kind of feel like Indiana Jones in regard to this bilge. Although I may just clean that lower floor up and re-tabb it to the hull sides. This would give me 2 transverse floors of 20" and another at 15" and last one nearest the head bulkhead of 12". Seems that attaching the two hull sides solidly would make more sense. In my head (being a novice) When the boat is under a strong heel and the keel under pressure and a load that the cross attachment of the hulls in the bilge would be necessary, but then again my knowledge of these kind of dynamics is not in my mathematical skills. This would make me feel better. As my son says best to build it not only to look good, but feel good. I appreciate any and all comments and suggestions ...

 

[kapnD]

The keel, the mast, and the stays all transfer considerable forces to the hull when the sails are deployed.
The transverse bulkheads are what keeps the boat from folding up under these strains.
I’d remove the plywood in the bottom, or at least cut an inspection hole in it just to be sure that there’s not a can of worms lurking down there.

 

[wesley Sherman]

That is what I am going to o in the next couple of day, pulling the bottom ply floor out by the engine bed. Was going to just tab in new fiberglass, but more I thought about it.. the more I am wanting to see below.. maybe the keel was the hiding place of some stolen gold or coin. I got to know I got to know. Lol And I hope KapnD I must say I hope there are worms in there or some hidden monster locked away for fifty years.