Boat paint

[PadrePoint]

Jacking up an end could be a good approach.  Never thought of that.  My floor is level enough that I could have used it to make a straight line along the sides.
The dimensions from bow to waterline and transom to waterline should be somewhere in the plans and a bit of math would reveal appropriate and relative heights of bow and stern from the floor. 

 

NICE to see your progress on your build.  

[Captain Tim]

Samantha,

If you search "how to apply the perfect waterline" this should come up. It will help if you read all the post (9 I think).

Designer

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Posted March 21, 2020 (edited)

Amos,

 

We do, here is that link.

Edited March 21, 2020 by Designer
fix it

[Captain Tim]

Samantha,

This may be faster for you. Click on How best and it all should come up.

 

[Hirilonde]

Yeah, like Don, no bottom paint, for the same reason

[Samantha Ritchie]

Thank you all for the replies!  That was VERY helpful.  We have the lines now for the bottom paint, and can add the lines for the boot stripe. 

 

We want to put bottom paint on for two reasons: first, where we live, at the base of Puget Sound,  barnacles attach  very quickly to the bottom of boats.  Second, we hope to do some lengthy cruises in this boat.  (We have been cruising in a Scamp, so the CS17 will be spacious.)

 

I'm going to look into that Devoe's Devthane 379.  Mark, your boat is beautiful.

[Captain Tim]

I was in contact with Systems Three about their Pennant Topsides paint. I purchased their Pennant Primer. They got in touch with me and asked if I had any questions. I told them I had wanted to buy their Pennant Topside paint but was told it had been discontinued. I was then told if they had what I wanted I could buy it. They did have what I was looking for and they sold it to me for a reduced price.

I was told they have a limited supply in stock but others could buy what they have.

Bottom line, if you were thinking of using System Three you should get in touch with them.

 Jeff Anderson    janderson@systemthree.com was my contact.

Good luck.

[Bryan Rolfe]

Just wanted to hijack this thread as I'm also deciding what paint to buy for our Spindrift 10. Our case is a very different use-case where the tender will spend considerable time in the water and live on deck. It will also be living in tropical climates. 

I was leaning towards something durable like a 2-part LPU paint, but a comment above that 2-part polyurethane paints don't do well under constant immersion has me second-guessing. I think we'll try to be good about pulling our tender out of the water overnight while at anchor, but we won't have davits, so it will have to be done using our mast or boom against the hull -- which is a long way of saying we probably won't always do it. Second, there's almost always some sitting water in a tender whether it be from rain, splashing, wet gear, etc. 

Edit: I did some more homework and confirmed that indeed polyurethane paints will not perform well immersed. It seems like the recommendation below the waterline is to just use an anti-fouling paint, which is kind of a bummer as they don't look nice, and when the boat is strapped down nest on deck, we'll be leaning up against and handling the bottom of the dinghy frequently -- and many of these paints are not the nicest things on our skin. 

[Aphers]

I used two pack polyurethane, for a tender that is in daily use. I do have davits and try to be good about always lifting each night.

 

I've not noticed any problems with the paint. Sometimes when I've been a bit lazy the bottom of the boat gets grubby with growth- it happens very quickly in 30⁰+ water!

 

I'm a big fan of the two pack. So much more durable than single pack. And don't even think about varnish...

[Captain Tim]

The Systems Three primer is waterproof and can be used for underwater surfaces. You will have to cover it with something for uv protection though.

If you are going to leave the dinghy in the water for long times you will want to have anti fouling paint on and that will be your uv protection.

It is real easy to use. It is water based so it cleans up easy and you thin it with water. 

[Aphers]

Put of curiosity, what is supposed to happen to two pack polyurethane if immersed for too long? I've not noticed any signs of degradation.

 

By the way, on the subject of paint, I recently added some non slip to the floor of the Spindrift. I masked up four areas (two in each half) and then painted using my normal two pack polyurethane with some non slip granules added. In the bow section I was more generous, because I found my feet slipped a lot on the sloping hull sides. In the stern I went for a more gentle finish. I tried to minimise the area that I painted, and I deliberately left a gap along the keel. The non slip works well but it holds dirt and tears up sponges, so you don't want it right in the bottom.

[Bryan Rolfe]

I'm not actually sure, but I think the polyurethanes can blister/bubble not unlike how a GRP hull can blister. I don't know the exact chemistry but it's probably a form of osmosis driving water molecules into the polymer network. 

I think you're probably right that, if reasonable care is taken not to leave the dinghy immersed in the water for days on end, then the 2-pack poly will probably last a long time still. 

[Aphers]

18 minutes ago, Bryan Rolfe said:

I'm not actually sure, but I think the polyurethanes can blister/bubble not unlike how a GRP hull can blister. I don't know the exact chemistry but it's probably a form of osmosis driving water molecules into the polymer network. 

I think you're probably right that, if reasonable care is taken not to leave the dinghy immersed in the water for days on end, then the 2-pack poly will probably last a long time still. 

I think that the real risk to a dinghy that isn't lifted most nights is that it will get too much growth on it, and you'll damage the paint as you scrape off the barnacles!

I totally understand why you don't want to use AF. I've tried hard/scrubbable AF as a boot top on my yacht, and was quite unimpressed- you couldn't touch it without it coming away on your hands. I think it would be a nightmare on a dinghy, it would get everywhere.

[Hirilonde]

I applied an ablative bottom paint over scuffed up solvent based LPU and left my Spindrift in the water at a dighy dock for 2 seasons.  Nothing but growth which came off with a sponge.

[BlueRidge]

I had Rustoleum’s Marine Topside paint on a wooden boat that looked great, but was a magnet for mold and mildew in Southern Florida.  

 

Some other wooden boat builders in my area used high quality exterior house paint with fungicides that prevented the mold and mildew but the finish wasn't as good.  

 

Is there a better way? 

[Don Silsbe]

I want to clear the air (slightly) on this subject.  When I contacted Interlux, it was about “topside paints” below the waterline, not two part poly (aka two-pack) paint.  They said blistering might occur after a short time (a few days) of immersion.  
 

Probably the smartest thing I could do is just bite the bullet, and slap some of this paint on the bottom.   But I really wanted a white bottom…. Has anybody used this stuff?

[Oyster]

My go to  bottom paints for boats that's design to sit largely on trailers, most of their lives, I stick to the Interlux Ultra hard bottom paints so that i don't get the chalky residue on my hands, body or on the bunk carpets. This is  the case with most Ablative paints. Now of course it cost more and most come in gallon only cans. But your prep work ,unlike if you want the fine arts finish from topcoat paints is fairly simple and straight foward.  Interprotect 2000E over your glass work after some fairing compound to fill the weave of course the paint over and proper prep work. This method had worked from this end.  

[JJVir]

@Don Silsbe Thanks for mentioning Devoe Devthane two part paint. It's in stock at Specialty Coatings in Michigan, where I live! I have been using System 3 Pennant topcoat (WR-LPU before that) but since they are no longer making it, I needed a different two-part paint. They are so durable.

[Aphers]

On 9/30/2024 at 4:07 AM, Don Silsbe said:

I want to clear the air (slightly) on this subject.  When I contacted Interlux, it was about “topside paints” below the waterline, not two part poly (aka two-pack) paint.  They said blistering might occur after a short time (a few days) of immersion.  
 

Probably the smartest thing I could do is just bite the bullet, and slap some of this paint on the bottom.   But I really wanted a white bottom…. Has anybody used this stuff?

 

I wouldn't use any sort of ablative paint on a boat that is going to handled in and out of the water a lot. It's unnecessary and will just make a mess.

 

I've used standard two part polyurethane all over my dinghy and foils. Four years in and I've yet to notice a single blister. The dinghy usually stays out of the water overnight but sometimes I get lazy and it goes a few days at a time without lifting.

[Lille Ø]

On 11/7/2023 at 4:04 PM, Bryan Rolfe said:

  I think we'll try to be good about pulling our tender out of the water overnight while at anchor, but we won't have davits, so it will have to be done using our mast or boom against the hull -- which is a long way of saying we probably won't always do it. . 

We have a double-ender just like you, and hence no davits. Only time we leave the Spindrift in the water for a bit longer is at the dinghy dock, or if we anticipate another dinghy trip in a few hours. Otherwise we always hoist it.

Takes just a minute or two. We rig a line between the bow and the quarter knees, and attach a halyard to that. Then we hoist the dinghy until it is on the level of one of our fender boards. Then tie the painter to bow cleat and another line from stern to mid cleat. Super stable there.

 

So far the two-part paint (Perfection, sadly no longer available) has held up well in the tropics, except for where it has had too many interactions with concrete dinghy docks or whatever. We expect to do some touch-up when we're anchored for the hurricane season.