False dory bottom planks - painted or raw?

[Thorne]

I've got the 3/4" DF false or sacrificial planks on the bottom of the dory (well the port plank isn't installed yet), but wonder if they should be painted or left raw?

The actual bottom is coated with CPES and red lead. The topsides of the false bottom DF planks are also coated with red lead and bedded in Dolphinite.

The question is - for a dry-sailed boat, should the false bottom planks be painted or not?

In some ways it seems logical to leave the bottom unpainted, so that the planks can dry out completely with no paint to hold moisture or rot against the real bottom.

http://www.luckhardt.com/bottom-planks2.jpg

http://www.luckhardt.com/bottom-planks3.jpg

[ 12-04-2005, 11:53 PM: Message edited by: Thorne ]

[Nick C]

It seems like paint would still be a good idea. Water passes through paint also, it's just a slower process. A good paint allows water out as fast as it lets it in, yet slows the movement of water both ways.

But... if you didn't paint the side toward the boat bottom, you probably shouldn't paint outside face. IF water can get between the bottom and the sacrificial piece then you want it to get out fast and painting the outside would slow that process down.

[Thorne]

Thanks, Nick.

Nope, no paint on the bottom.

The layers are:

wood bottom both sides coated with CPES and red lead. Dolphinite on bottomside

false bottom topside coated with red lead.

The previous owner let the bottom planks get damaged a bit by letting the plywood false bottom rot with rainwater.

I had to replace two of the floor cleats and CPES the heck out of the bottom planks. They seem strong enough now, and the false bottom should take any abuse the trailer/rocks/ beaches may hand out.

So I really don't want this new plank false bottom to cause any rot, which is why I'm considering leaving it raw.

I have lots of good paint and CPES, but as you said, don't want to seal any moisture against the bottom planks.

[ 12-05-2005, 12:58 AM: Message edited by: Thorne ]

[Bob Smalser]

I use red lead all sides followed by copper bottom paint.

Protects the wood and keeps the slime to a minimum.

[ 12-05-2005, 11:03 AM: Message edited by: Bob Smalser ]

[Gary E]

I've got the 3/4" DF false or sacrificial planks on the bottom of the dory Can you 'splain to is WHY they are needed?
It's a small boat...no?

False as in "not true" or it's not really the bottom?

Sacrificial as in what is being sacrificed? for whut purpose? Is there some double bottom boat god I dont know about?

[Thorne]

Thanks again, Bob -- I happen to have some lovely anti-fouling paint that will work well.

Gary -

Sorry for the "dory esoterica".

There probably is a God for small boats -- He's the older guy with the beard and Greek Fisherman's hat at the bar in the Yacht Club, third from the left...but the only sacrifices he demands are money, time and dampness.

;- )

Dories are built around the bottom planks, and replacing them isn't much different from completely rebuilding the boat. Gardner's plans for some dories call for a second / false / sacrifical bottom made of fir / pine / ply to protect the essential bottom planks of the boats.

The protection is mostly for the rocky shores of Maine -- which are a fur piece from California's mud and sand, believe me! But since it is in the plans, and the bottom planks of my boat were damaged by rot from rainwater and a plywood false bottom, putting the 3/4" fir planks on is a VERY good idea.

[mmd]

It is quite common to place sacrificial "rubbing strakes" on the bottoms of Lunenburg style and Shelburne style Banks dories, but much less frequent to put entire second bottoms on them. Bluenoser frugality, I s'pose.

Commercial boats for the schooner fishery were fitted up all dry and painted after completion 'cause longevity was not a concern - the boats got so beat to crap during a working season that the concept of using the boat for a second season was almost laughable. Nowadays a bit longer lifespan is anticipated, so the rubbing strakes are painted with red lead on both faying surfaces prior to installation.

Regardless of what "goop" you use as a bedding agent, remember that the whole idea is to be able to easily renew the sacrifical bottom planking, so don't use anything that sticks like a burr to a wool sweater.