Newbee with 1969 20' SF

[mentalfloss]

You guys are not going to believe this crap! When we removed the console and tower, to move it forward, we had to grind the "hump" in the floor that was were the console used to set. Long story short, the floor is rotten pretty bad. Bad news is that I need to pay to replace the floor ($2500), good news is that can now raise the floor to self bail. Maybe a God or karma thing....
What height do I need to raise my floor to? I would think that it should be a couple inches above the waterline. Also, can you suggest any changes while we have her floor removed?

[NoBones]

Believe me at our ages there is nothing that surprises us any more!

Raising the deck 2 inches will be fine...

[mentalfloss]

Raised floor 3". Moved fuel tank forward 16" and put it under the floor. Custom cooler/ fish coffin in the floor, forward of the gas tank. Batteries going under the console. She should self bail now!
I am considering putting closed cell foam into the outer sections of the hull. Not down the middle were the gas tank and coffin are going. Can anyone give me some feedback on this? Will closed cell soak up water? Is this a good idea in general?

Thank you again

[seacraftks]

great boat

[seacraftks]

boat

[Vandy]

Here is the back of my 69 Seacraft that has a modified splashwell. It was like this when I bought it. The height has come in handy a number of times keeping rollers out of the boat. The only thing is I can not fully tilt the motor out of the water as you can see in the second photo.

[WildBill]

I'm new to the forum so forgive me if someone had seen this one before. My first SeaCraft was a '79 23' Septre that sunk behind our hotel one early morning on Lower Matecombe west of Islamorada about 15 years ago. We always took on excessive amounts of water while fishing offshore and my 1100 gallon rule pulled major overtime. We looked and looked, filled the bilge with a hose when the boat was out of the water to no avail. One day my buddy Glen sunk his 23SF Potter hull off of Marathon and he commented that his bilge was full when it went down. He and a buddy were in the back corner trying to fish a trippletail with a net out of a 55 gallon drum floating on the surface about 10 miles outside of Sombrero light when a rouge wave came over the back. It went down in seconds! He was fishing with his dad in a second boat not too far away and was able to barely get off the Mayday. What we found out was that when the boats were manufactured and they installed the inner liners; the thru hulls for the live wells were only castle nutted inside of the live well. So when the boats were under way the inner liner would move and water would come into the bilge between the thru hull and the hull. After I pulled mine from the drink it sat for months being that I had already rebuilt it in Homestead after Hurricane Andrew. I eventually pulled the thru hull and sealed it with 5200 and castle nutted it to the hull and both sides of the live well. I've since sold it to a guy in Homestead and now am rebuilding a '73 20SF. I think now looking back that I should have sealed the hole, moved the location which was directly under the live well and plumbed it with flexible hose to eliminate stress from the movements of the hull and inner liner.

[uncleboo]

Cut it, seal it and put some hardware on it. It'll work just fine.

[Bigshrimpin]

Originally Posted by Bushwacker

Mentalfloss, with all due respect, you (and anyone else running a similar motor, or even a V-6 E-Tec or Optimax on a 20 sf or Seafari) should seriously consider adding a raised splashwell. The one in picture below in Kevin's 78 20sf would be a MAJOR safety improvement! This is the OEM raised splashwell option that Potter came out with in the late 70’s. Suggest you send a PM to Pianewman (Ed Newman) who is looking at having Don Herman build a batch of them. Check out this thread (http://www.classicseacraft.com/commu...ad.php?t=23137) that Ed started for more pictures. The more guys that sign up, the cheaper they’ll be!

Regarding the safety issue of low transoms and splashwells, anyone that hasn’t seen it should checkout this thread (http://www.classicseacraft.com/commu...ad.php?t=23037) about Mitchman’s 20 sf that went down suddenly off Martha’s Vineyard a couple of months ago! Mitch’s boat had enough water in the bilge that the stern went under when he opened the throttle, so I don’t know if this raised splashwell would have saved his boat, but I can’t help but wonder if it would have kept lots of water out of the boat long enough for it to accelerate away from the stern wave and maybe have bought him some time to start pumping the bilge with a manual pump!

When Carl Moesly designed the 19/20’ hulls in the mid 60’s, the biggest outboards were less than 300 lbs and the boats were easily self bailing with those motors. I believe he actually designed them for the I-6 Merc, which was very light (weighing something like 260 lbs?!) The much heavier V-6 motors came out in the late 70’s, and Potter raised the decks and came out with this raised splashwell accessory about the same time. He deserves credit for evidently recognizing the potential problems with the heavier motors! However I believe those early V-6’s were still under 400 lbs, and folks are now installing motors weighing 450-500 lbs, so the self-bailing issue is changing to one of self-sinking! Notice that all the 18's, 20 MA's, and O/B 23's which Potter designed in the 70's also have a full height splashwell!

BoatUS publishes a great magazine called Seaworthy (http://www.boatus.com/seaworthy/sinking/default.asp) that summarizes “Lessons Learned” from reviewing claims from their insurance division. (This is wisdom, as defined by Fr. Frank . . . learning from other peoples mistakes!) The July 2006 issue contains a 3 page article on why outboard boats sink. Of all the boats that sank underway, MORE (32%) sank due to WATER OVER THE GUNNELS/TRANSOM than any other single cause! In one case, a 25’ boat sank off Fisher’s Island, Ny. "because 3 big guys went aft to fiddle with a stalled engine and the boat’s already-low transom was shoved down even further. A wave broke into the cockpit. In the span of only a few seconds, two more waves came aboard and the boat began sliding underwater.” The article said it sank so fast that they barely had time to grab life jackets, and this is a LOT BIGGER boat than the 20 I'm talking about! If you click on the “Taking water over the gunnels/transom” heading in the article in the link above it brings up the following 5 paragraph summary:

“The single most critical reason boats are flooded on open water has to do with transom height. Thirteen of 15 boats in the sample group that were swamped were outboard powered, with engine cut-outs that were often only inches above the waves. (Of the two remaining boats, one was an inboard with very low freeboard that took a wave over the bow and the other was a sailboat that was knocked down and sank when water entered an unsecured cockpit hatch.)

Motor wells are supposed to be the second line of defense when a wave comes over an outboard's transom but, in some cases, the well is TOO LOW, TOO SHALLOW, and/or not sealed adequately to the cockpit. Scuppers in the motor well and cockpit may also be slow to drain, especially if they're clogged. And whenever water lingers in the well or cockpit, the chances of another wave coming aboard increases. So too is the risk of being swamped.

Aside from transom height, the other contributing factor when a boat is swamped is typically weight distribution-- too many people at the stern together with scuba tanks, large coolers, BAIT WELLS, etc. that reduces buoyancy aft. In most cases, the boats were stopped or idling. The one exception was a boat that broached while entering a breaking inlet.

It should be noted that boats under 20' are required to have level flotation, so many of the boats in the study remained awash, although several were rolled over by the waves or by passengers rushing to one side of the boat.

PREVENTION: Especially on outboards with low cut outs, be conscious of weight distribution. Avoid storing scuba tanks, heavy coolers, etc. near the transom At slow speeds, keep the boat moving toward the waves. Don't anchor from the stern.”

Sorry for the long-winded post, but I thought that it was warranted, given Mitchman’s recent close call and the disturbing trend of folks installing motors much heavier than these boats were originally designed for! If we’re going to violate the original design parameters for the boat, it seems to me that we should at least compensate by raising the splashwell height to keep big waves out of the boat when the overweight motor tries to sink it! Denny

AMEN!!! the first generation 1979 - 1983 v6 merc 200/225 were only 339 - 360lbs. The 18/20's ride much nicer with light motors cruising 20 - 28mph.

[mentalfloss]

Thanks for all the great info!
The boat is getting closer to being done. I had the transom rebuilt with Aqua Tech plywood. Stringers looked good. Raised the floor up 3 inches. Removed the casting deck. Foamed the outer 2 sections of the hull. Installed new floor. Had the outer hull sanded and gel coated. They are working on the inner cap now.
Can you look at the pictures to see if it looks like they are doing things correctly?
Also any opinions on time and cost. It has been 14 months to get it to the stage it is at and about $14k.