what is the function of the keel stringer?
 

On the older (70's) 20 cc boats, what is the function of the keel stringer (the laminated piece that runs the length of the boat. It's the only active core stringer on the boat and is totally rotten in most of the hulls of this vintage.

A few experienced boat builders have told me that the keel stringer core does not really lend much at all structurally, it's the glass doing all the work.

This is 2x4 with a rounded top that runs the length of the center of the boat.

If the 4 main inactive (hollow) stringers are in good condition, is a wet core in the keel stringer a problem?

Any feedback and knowledge would be great.

Re: what is the function of the keel stringer?
 

Carefull who you listen too. If people are telling you it worthless or do not know the purpose of it, you may want to find others who do.
Think in geometric terms for that stringer, hollow or not.

And no my '72 23 ('71 production) is not rotten as you may think.

Re: what is the function of the keel stringer?
 

This is a great question I whish I really knew the answer to it. I have the 23 and with the longitudinal steps plus the foam filed stringers I also was wondering if that center wood stringer war really needed. But I would rather have a Ocean Boat that is over built then under built any day. I don’t get any flex in the hull when I am going through 2’ to 4’ and everyone that goes on my boat says it rides like a Cadillac. If that stringer helps provide the ride that makes the old SeaCrafts have the reputation it does than “I Like That Wood Center Stringer”.
FellowShip [img]images/icons/cool.gif[/img]

Re: what is the function of the keel stringer?
 

Yeah, I would also like to know just what specific purpose it serves, it must lend rigidity and would it be seriously compromised by moisture? Can someone answer the question?

Re: what is the function of the keel stringer?
 

My 78 23' has the same rounded stringer but I thought it was half a PVC pipe glassed over??? I have never heard the wood deal before and I've owned two seacrafts since the 70's. Anyway I do know that there should be a piece of nylon rope sticking out the side of the box foam filled stringers(aft inside) This rope acts a a "wick System" (like a candle) and any moisture that builds up in the foam will follow the wick out and drain in the bilge. I have seen the same system in the "Haupner" flats boat built by Ocean Master here in Jupiter fl. Wonder why they have the wick system? Bill Potter was working with them in design!

Capt Chuck (shellback)

Remember if she asks"how much did that cost?" LIE!

[ October 31, 2003, 08:22 PM: Message edited by: capt chuck steele ]

Re: what is the function of the keel stringer?
 

Capt Chuch,

Nylon huh ? Where exactly was this pc of nylon. I'm in the process of re-doing my boat and have not seen this. It makes sense though, the moisture will head to the lowest point.

I will re-install this if you can tell me exactly where she goes.

Oh, and I have wood stringer too. It makes sense that it adds some rigidity between two opposing sides of the hull...

Re: what is the function of the keel stringer?
 

abl1111

I don't know about reinstalling this wick or not. I think it might run the entire length inside the box stringer like a candle? I almost cut mine off the first time I discovered it as I thought it was the plug they used after pumping in the foam or something during construction that they left in there. For example: If I go to the round inspection plate at the transom on the port side and take my left hand and reach in pushing my hand forward toward the bow between the inner liner and the stringer I can grab the wick. It's about 1" diameter and approx 5" long. I don't remember what the hell I was doing in that position to begin with when I discovered it but "viola"

Capt Chuck(shellback)

[ October 31, 2003, 08:24 PM: Message edited by: capt chuck steele ]

Re: what is the function of the keel stringer?
 

It would be great to hear potters response.

I look forward to hearing his reply to this.

If you could...

ask him how it could lend to the boats stiffness if the 4 main stringers are so stocky and overbuilt.

Re: what is the function of the keel stringer?
 

I should have been more clear...

my concern was with dampness, not rot...however, they are all too often related.

Thanks again for your help with this. Any relevant info on the stringers and their relations to each other would be helpful.

Re: what is the function of the keel stringer?
 

Mine was rotten. I tore it out and replaced it with 1/2 round 4" PVC/ I then covered the PVC with 2-3 layers of roven woven.

I use the inside of the 1/2 round as the drain to the bilge from the fwd compartment.

My Contender uses the same theory, I just copied it.

Give me a year or two to tell you if it works but so far so good.

I have been able to lift the hull up with a floor jack, placing the jack directy under the bottom center of the boat, so replacing the wood with PVC/ Glass has proven plenty strong.

Re: what is the function of the keel stringer?
 

Ok, so if the glass is intact & in good shape on top of a damp stringer, wouldn't it be doing the same thing as a half round with glass?

Re: what is the function of the keel stringer?
 

On mine there was only 1, maybe 2 layers of WR so I do not think so, no.

There was not enough glass covering the center stringer to compensate for the loss in integrity of the rotten wood.

Re: what is the function of the keel stringer?
 

mada

I tried to call Potter. Both numbers I had for him were disconnected. Maybe Hermco who deals with his Seamark Bracket could answer your questions. I questioned Mike @ wildfire Marine. He said they are wood and had never seen one that was rotted, just a few that were damp. He said that it provided stiffness to the keel.

[ October 31, 2003, 08:24 PM: Message edited by: capt chuck steele ]

Re: what is the function of the keel stringer?
 

Mada-

I read on the Hull truth you may be looking into buying a Contender? If so, what size?

By the way, my 1999 25 just happens to be for sale [img]images/icons/wink.gif[/img]

Re: what is the function of the keel stringer?
 

Trayder,

Don't think I wasn't diggin' that boat, but the $$ is over my head for now.

I'd like to get into a bigger boat, either a 23 seacraft or an older contender. But the price has got to be right for my budget.

What kind of boat do you have/want?

Re: what is the function of the keel stringer?
 

I have a 1969 20 SeaCraft CC and a 1999 25 Contender.

I do not use the Contender any more and my better half does not think it makes as nice of a yard planter as myself.

So it is up for sale. It is one of the best riding boats in its class and I will miss it alot when it is gone but it makes no sense for me to have it right now.

Re: what is the function of the keel stringer?
 

Trayder,

I know the feeling. Especially when capital is a little scarce.

[ October 07, 2003, 11:18 PM: Message edited by: Otto Cuyler ]

Re: what is the function of the keel stringer?
 

<font size="2" face="Verdana, Helvetica, sans-serif">Capital? What's that? OHHHHH, you get that with WORK [img]images/icons/shocked.gif[/img]

Re: what is the function of the keel stringer?
 

Capt Chuck ...Don.... any word ???

Re: what is the function of the keel stringer?
 

I think the original purpose of the keel stringer is masked in mystery and suspense. So, years later - people would ask, "What is the purpose of the keel stringer". And others would respond, "I know, I know, it's...it's --- ahhhh, I don't know. I think it's a... no, that's not it... "

Until one day, a committee was formed around the importance of the keel stringer. There were some that thought it had significant meaning and others who didn't think it was that important...

This went around and around and around and around.......

Re: what is the function of the keel stringer?
 

Yet another season has passed. Now that we have a lot of time on our hands, why doesn't someone volunteer to cut (LT) the keel stringer out of their hull, put it back together, take it out in 8'-10's and let us know if you can tell the difference. Video would be helpful...

Re: what is the function of the keel stringer?
 

Scott

I have not seen a response from Hermco yet? I think OC Skip is on the right road thou!

How about it SeaPotter [img]images/icons/confused.gif[/img]

Re: what is the function of the keel stringer?
 

The keel stringer supplies longitudinal stiffness to the hull. It is often utilized as a connecting point in larger boats as they are often made in 2 halves and bonded together - the keel stringer adds another bonding point. As stated in an eariler reply, the wood does not supply the stiffness - it is the geometry. The taller the stringer the stiffer the the boat. Often they are hollow. The wood was a simple way to preform the glass materials. The only place stiff materials are required is on the top (stringer cap).

Re: what is the function of the keel stringer?
 

I will ask Potter today.He was here yesterday and I forgot.My opinion is that it was to stiffen the keel area but we will see what Mr. Potter says. [img]images/icons/grin.gif[/img]

Re: what is the function of the keel stringer?
 

If you can, ask potter about the other four stringers in relation to that keel stringer. Thanks!

Re: what is the function of the keel stringer?
 

He should be here today to finish off his yellow 20' I will see if he will log on and answer the question. You can see his 20 at http://www.hermco.net/new_page_1.htm

[ November 04, 2003, 08:49 AM: Message edited by: HermCo ]

Re: what is the function of the keel stringer?
 

DON

Boy I like that Seacraft Decal!! "Potter Built 2" Is that a new patent? Can I have one? I'll drive by the shop to get it [img]images/icons/cool.gif[/img]

Re: what is the function of the keel stringer?
 

One of Potters sons had that made. I don't know if he can get more or the legality of it but he will be here soon and I will try to get him to logon. [img]images/icons/cool.gif[/img]
http://www.hermco.net/Potter203.JPG

[ November 04, 2003, 11:15 AM: Message edited by: HermCo ]

Re: what is the function of the keel stringer?
 

Potter tells me the wood keel and the later pvc was to stiffen the area because most trailers were using rollers that would stress the keel. [img]images/icons/grin.gif[/img]

Re: what is the function of the keel stringer?
 

Don,

What kind of SeaCraft is that?

Looks like a cross between the seafari and a sceptre. [img]images/icons/confused.gif[/img]

Re: what is the function of the keel stringer?
 

Was called the Overnighter.Potter says it was the last one he designed and they only built about a couple dozen.
[img]images/icons/wink.gif[/img]

[ November 04, 2003, 02:58 PM: Message edited by: HermCo ]

Re: what is the function of the keel stringer?
 

EBEACH,

Does it have purpose while underway? Or is that what the other four beefy stringers are for?

Thanks again for your help unraveling this mystery.

Re: what is the function of the keel stringer?
 

Sorry that last reply should have been pointed at HermCo

Re: what is the function of the keel stringer?
 

Was not necessary when underway but I'm sure it didnt hurt either. It was primarily to stiffen the keel area that rode on the trailer rollers.
[img]images/icons/grin.gif[/img]

Re: what is the function of the keel stringer?
 

HermCo,

Thanks for your help with this. I guess we can put this string to bed.

I'm glad I found this thread. Anyone see a problem with removing about the first two feet of the center stringer and beefing up the keel?

not a problem at all. Just make sure you add some glass to strengthen the area up.