Should a keel trunk have any flex to it?

[hawk232]

well the good news is that we made it out for the maiden voyage yesterday! sailed for a solid 45min (my first time sailing without someone who knew anything and only my 3rd time EVER sailing) before rain hit. we went and hung out in the cabin hoping it would pass (gave us a good chance to see that just about every single bolt leaks!!). well it didn't, I ended up sailing halfway back to the ramp before the wind just wasn't moving me fast enough (it was cold in the rain) and I fired up the ole merc to bring us in. anywho, while sailing back in I was looking into the cabin and anytime the boat would shift (wave, gust, etc...) the keel trunk would move a little. since so much of the boat is rotten I assumed that this was the case for the trunk. after lowering the keel and looking in there, there doesn't appear to be any wood in there, which has made me doubt the original idea that it IS NOT supposed to flex?!!?

summary: should the keel trunk flex when the boat moves around? see pics of trunk if that would help...

 

[centerline]

just being honest here. not critisizing....

the trunk shouldnt move... movement is flexing, flexing is stressing.

as can be seen in the couple of photos you posted, the wood that keeps it rigid and seaworthy has been compromised with decay. and we dont know for sure if the compression post is doing its job anymore, but we can assume it isnt. we must also assume the other important parts like the deck core and deck/hull joint isnt in any better condition (due to leaking deck hardware attachment points).... these are all rather important items designed in within the fiberglass shell as it was layed up so it could be assembled in to a seaworthy boat.... from the photos and what you have said, the hull apparently no longer has everything it needs to be a good stiff boat...

so, are you sure the keel trunk is flexing, or is the rest of the hull flexing around the trunk while the keel/centerboard is down in the water doing its job?

 

[hawk232]

centerline, you were not criticizing, just stating the obvious! I bought the boat for $500 so I expect problems!!

I am not familiar with what provides the structural integrity on a sailboat, but I seriously doubt that the rotten benches were ever designed to support the hull as they consist of a single strip of 6" fiberglass cloth (not mat, or biax etc...) holding a single piece of 3/8" non marine grade (full of voids) ply down to the hull, not even a sort of structural design. that being said, I do not deny that this boat has ALOT of rot! the deck forward of the hatch is rotten (all around the mast is solid and all stays/shrouds bolt through the hull itself). as for the compression post, it has a little movement in it so it is not doing is full job, though it could only move a little. that is an easy fix and if the general consensus is that the trunk shouldn't be flexing, I can easily fiberglass some braces to keep it in place (I have 5 gal of vinylester resin and tons (two rolls) of 1708 biax cloth in the garage for another boat rebuild that I am doing).

the goal for this boat is to last well enough and to be safe enough to show us the basics of sailing and to tell us whether or not we should spend more money on a better boat one day or to get out of sailing altogether.

 

[bffatcat]

weighted centerboard trunk flexing

Its obvious your a novice Did you have anyone look at this boat before u bought it. It looks to me like a major repair job The trunk should not move period It looks to me from the pics that somebody did an ineffective patch job on the trunk Here is my opinion Ive got over 50 years of sailing experience. plus extensive repair work. Try to fix what you can yourself. I wouldnt put a lot more dollars into a boat like this. If you cant fix it and get it in reasonable sailing condition you might consider donating it to charity if you can find someone to take it. At
worst your going to have to break it up and haul it to the dump in pieces. Next time around you will know better. You cant get much of a boat for $500 good luck

 

[higgs]

The centerboard trunk should not flex. At some point that flexing will lead to a leak, or, at worst, a catastrophic break.

 

[hawk232]

no, I had nobody look at the boat, as you stated, its a $500 boat!! I knew exactly what I was looking at as I have replaced strigers and transoms in several boats (ie I am very familiar with the symptoms and identification of rot).

what I am trying to determine with my questions is what should be of concern, and what is simply asthetics? what are the structural components which I should be repairing? the boat does not have a stringer system (as I outlined in my previous post). the trunk is only fiberglass, there is no core in it. the deck is soft but all of the stays and shrouds bolt though the gunwales and the bow and stern (no core in those either). so right now, it seems that my compression post and keel trunk need some attention. what other structural components should I be looking at?

 

[centerline]

any fiberglass boat can be fixed up... time and money... lots of each

do you know how much of the compression post is missing (rotted away).... i had a mac 21 and i removed the original, and still solid, compression post while i was doing some work on it, and the cabin top sagged almost a full two inches without the compression post in it.....

the cabin roof has to be jacked up to pull the hull tight to insert or remove the post, so when you load the chainplates with the rigging from the mast, the whole hull is taut and rigid and nearly in/unflexable.... again, flexing is stress, so when large seas hit a boat with loose rigging, things are likely to fail.
the compression post is the link between the rigging and the solid foundation it needs to make it all work together as one. it has the be the correct length and be able to take the load. i would say a working load of around 3000lbs at times.

so if the compression post is missing a bit off the bottom, it could be allowing the hull to flex and twist in a way that it shouldnt be doing, and letting you see it in the keel trunk in relation to the surrounding hull....

EDIT.... one more thing i will add, the cored deck that has became soft is supposed to be rigid and an important structural part of the boat... it keeps the sides of the hull spread out when you pull the shrouds and stays tight. if it flexes too much you wont be able to keep the rigging tight....

 

[hawk232]

good info centerline, I will see if I can dig up specs on the length of the compression post and take measurements. right now it appears that its only 1/4" too short but if my deck should be 2" higher like yours then its 2 1/4" too short!!!

I think I may add some bracing to the trunk as well. the boat originally had a sink that went from the trunk to the side of the boat and may have been used to limit flexing. that sink is gone so I will just fiberglass some gussetts in to hold it still.

my goal is not a full restoration, I just want to boat to be safe until we can decide if we like sailing enough to spend $$ on a nicer boat. thanks for all of the replies!

 

[centerline]

if there is any doubt on the length of the compression post, a half inch too long is better than a half inch too short....

 

[hawk232]

Oddly enough I just went and checked and with the mast up the post does not move at all... Apparently it's only loose with the mast is down...

 

[justsomeguy]

Oddly enough I just went and checked and with the mast up the post does not move at all... Apparently it's only loose with the mast is down...

Hmmm. That tells me your deck is flexing. Like Centerline said..."a half inch too long is better than a half inch too short...."

 

[higgs]

I would not be comfortable sailing this boat in anything but light air. Fixing it is undoubtedly more costly than the boat is worth.

 

[hawk232]

alright so at this point I am going to replace the compression post, add some bracing to the trunk (just double checked and its not the hull flexing) and add some support under the deck in the bow area. all of the stays/shrouds pass only through glass, no wood to be rotten and I have checked that base of the mast and the wood there and in the surrounding areas is still sound. any other areas I should be looking at?

edit: higgs: I have noted your advice and hope that there will never come a day when you can say "I told you so"!!


thanks again for the advice everyone. I am not afraid of a little work. I just don't know the main areas of concern on a sailboat like I do on a powerboat. for anyone interested in seeing why this little bit of work doesn't phase me too much, have a look at my other ongoing project! http://www.bayouboaters.com/forum/showthread.php?1105-1986-Paramount-restoration

 

[justsomeguy]

You might be able to shim out the difference, as long as everything else is rigid.

I think.

 

[hawk232]

shim the difference on the compression post? if that's what you mean... heck its easy enough to just make a new one that it wouldn't be worth the bother or the gamble on shimming it! I measured and its just a 2x4...

 

[Merlin Clark]

You'll want to make sure the trunk doesn't snap off and send the boat to the bottom. No common pleasure boat bilge pump is going to keep up with a hole like that.
If $$ are tight, I'd buy a gallon of polyester or vinylester resin and hardener and a couple/3 yards of mat and patch that beast up. Epoxy is easiest/best but more money.
The West System website has tons of good info on making repairs, free to download.
sand/grind the paint off (to good looking glass) of the junction of trunk and hull, clean it and layup about 3/8" of glass all around, graduating from about 2" wide strips to about 8" wide (half on trunk and half on hull.
Once that is done, make a new compression post out of a couple clear fir 2x4s screwed and epoxied together (shape as desired, round- octo- whatever) or a piece of aluminum tubing and replace that nasty rotten plywood. Carry the main bulkhead (forward settee) all the way across to brace the comp post and trunk. You can use dry PT plywood for this, it'll last and not expensive.
I say dry because resin won't work with wet wood and you don't want it shrinking after it's installed.
Take the mast down rather than fight with it.
Get this stuff sorted out and we'll talk about what's next.
I wouldn't sail the boat at all until the trunk is fixed.
Cheap boats aren't really cheap and a free boat is usually hell but all boats need something.

 

[hawk232]

I already have 5 gals of vinylester resin, 1 gal of expoxy, a roll of 50" wide biax and a roll of 38" wide biax... I have the glass covered!! I am going to just make a gusset to run from 3/4 of the way up the trunk to the floor almost at the settee, make one for each side out of 3/4" marine plywood (also on hand) and laminate it in with a full biax wrap and finish it up by tabbing in one or two strips of biax tape.

as for the compression post, you recommend that over the 2x4 that is currently in there?

in searching for factory compression post length I found reference to a guy with an Ensenada 20 who was not happy with the factory support for the trunk as he was getting excessive flexing... that makes me feel a lot better!!

 

[Merlin Clark]

Sounds like you've got it down Hawk.
if the 2x4 were the end of a bulkhead I'd leave as is but with a single board like that I'd beef it up to ensure it stays "in column".
could make a t out of it (cross section).

 

[centerline]

yes, the post will be tight when its loaded with the mast and rigging tension, but the compression post needs be under compression before its loaded with the mast....

think about what you would see happen to the hull if there was no compression post in it and a very heavy load was slowly lowered onto the spot where the mast sits..... the hull and cabin top would get wider and flatter for a while... but wider and flatter has no rigidity. but when you jack the cabin top up the other way away from the lower part of the hull, it will become more rounded in every direction, and it will create strength by making the top more rigid due to its shape.
the bottom half of the hull is already made so much stronger with materials and by design, that when you put the compression post in to hold its shape that way, the two halves of the hull will almost become one solid piece.
you then have something that should stand up to the outside pressures that will be placed on it.... the mast pushing down and the shrouds and stays pulling upwards.

and dont even try jacking it to install a new compression post with the mast in it. it WILL absolutely cause damage somewhere....

lower the mast to do the work, then when you have the new post installed under compression then you can raise the mast again
but it wont go fast because you are going to have to re-adjust ALL the rigging to tune the mast and get it all to fit the boat again....

 

[Benny17441]

Check with other Balboa owners which may be able to advice in more specific terms.