Trimaran - Especially Searunner - Owners

[Cavalier MK2]

Seriously, on this sticky subject latex should be considered in those 3rd world conditions. It is designed to stay on a surface for 20+ years after a hurried prep usually involving a pressure washer and no sanding. Your boat should be sanded and rinsed for best results but you won't suffer catastrophic failures if you miss a spot. It tends to stay on and wear down unless what is underneath lets go.

[Mark Johnson]

BARNACLES, SLIME, and SEARUNNER CENTERBOARD'S UPS & DOWNS:
Ross, I may have some answers for you, but this is so important to the Searunner crowd, I thought I would tackle it in a broad general way.

Searunner centerboards, along with their huge skeg rudders, make our craft what they are... "The best of the ol woodie but goodies". They can also be a complicated pain in the ass.

Knowing this to be the case, we set out to prevent this from the get go, and most of it worked as planned, while other ideas did not.

LOTS OF PROTECTIVE GLASS:
After lightly glassing & sanding "to perfectly flat" inside the trunk, and the Delrin through hull fittings for the 5/8" silicon bronze axle pin were caulked in, I made a large 5" wide epoxy fillet around the through hull's mushroom heads. This made the 1' circle around the through hull a gradual 3/8" hump in the middle of the trunk. THEN we glassed everywhere in the trunk, including over this hump, with two layers of 10 oz fabric, and applied 4 epoxy topcoats. The through hulls were now buried under an epoxy ramp & glass, so we cut out their centers to accept the pins later.
Next we glassed the ends similarly, over the previously applied fillets.

At the bottom, where it exits the minikeel, we made large 3/4" radii, and glassed these all around, with 6 to 8 layers of bias cut glass tapes. All of the minikeel is about 3/16" thick, except the bottom & nose, which is more.

So... the trunk was WELL glassed & tough! Since we pull the CB out of the boat from above, this extra glass at the bottom of the trunk, and subsequent narrowing of the slot, was OK.

I HATE "CLUNKERS:"
On the 34, some things may vary from the others, but... We have a split hose at the top, for a "0" tolerance but cushioned fit. At the bottom trunk's slot, I applied more and more glass to the 1' long bearing area, at the radius (forward end), just at the point that where board is fully down. I added glass until it is almost "0" tolerance at the bottom slot.

When the board is up, there is almost a finger's width on each side, but when down for sailing, the bottom tip of the board can only swing side to side about 1/16" or so. It doesn't "clunk" in a seaway, even dead down wind. I also glued into the CB, a 4" long section of thick rubber hose, into the already HEAVILY glassed axle pin hole. This is for further cushioning & sound proofing.

WHAT IF I GO "BUMP"?
I wanted to hedge my bets in future groundings, so glassed the hell out of the board. The glass is about 1/8" thick everywhere on the sides, going to 1/4" thick on the bottom, 3/8" thick on the leading edge, and right on the small "strike zone" area where the bottom meats the nose, it is almost 1/2" thick! That takes a LOT of those bias cut glass tapes, and a LOT of fairing it out.

We have touched bottom a number of times taking out a chip, and a crab pot line's barnacles dug 1/16" groves along the sides once, but it never got to the wood, or even close. This allowed me to wait years if necessary, before effecting a repair. Because we attach a 1/8th" parachute chord to the CBs down line, and cam cleat only the chord, it acts as a fuse. If we hit something, the chord breaks, and the board kicks itself up with a gentile thump. (This is due to the short section of 3" rubber exhaust hose attached onto the top of the CB trunk's fwd end wall).

My approach was not to use a more water resistant core material, like Roy has done on his new CB. I went with the much harder wood core as drawn, but with SO much glass in impact areas, that it stays encapsulated. I applied the same reasoning to the rudder/skeg as well. I think either approach is valid.

My board is of coarse way heavier, but is still so buoyant that it is hard to crank down. Very little of this is friction, as once it comes up a bit, it is a loose fit. There IS the additional friction of the slot's rubber flap, however.
Roy's idea is much lighter of coarse, I just hope it is not too hard for him to crank down. I think that the 40's CB is controlled differently, and perhaps has better mechanical advantage than mine, so should still be manageable. On the 34, the approximately 2' of control rope pull, goes from full up to full down, so it is actually at a mechanical DIS-advantage.

THOSE DAMNED TURNING BLOCKS:
After over 17 years of sailing Delphys hard, and blowing up 4 of the CB down line turning blocks, (1,700# WL Ronstans), I finally got fed up. I switched these control blocks out for SS Harken ESP foot blocks, #6076. These are 2,500# WL, & 5,000# BL, with a 3/8" axle bolt! It has been several years, and they hold up to salt water well. We also raised this down line block in the trunk by 2", so that it can be reached from above. This resulted in a bit less board down, like 5%, but the boat balances better. This is a good preemptive replacement, btw, for anyone heading on a world cruise.
Harken

THE RUBBER FLAP:
This did and didn't work. I don't know how many Searunners have this feature, but it was drawn on the 34's plans. I made & installed several types of rubber flaps in my boatyard before launching, and settled on some RUGGED 1/4" thick reinforced conveyor belt material.

It was originally full length, and worked great when I pushed the board up from inside my grave sized "board pit" in the boat building. Then, a year and a half after launching Delphys as a bare hull, we stood the new mast. I now had a mast winch that would allow me to crank the board down for the first time since launching. On about the 10th try, the back half of the flap inverted when raising the board, and it jammed SOLID! Two full days and two SCUBA tanks later, I had "hand sawed" off the offending part, and freed the CB. WHEW!

The problem with the flap idea is that at the slot, the front half of the CB is going mostly fore n aft, while the back half of the board is going mostly up n down. The back half of the flap could, therefore, jamb, If fact it wants to.

I split the difference and cut a wide slot in the back half of the rubber flap, while keeping the front half.
Finally something that touches on Ross's question... In year one, while we had the full rubber flap intact, even though we had only "Copper Crapsky" coating the trunk & board, (which does NOT work), we never had ANY growth in the trunk or on the board. NONE!

Seal off the light and their food supply, and the buggers will not go there. Ross, I obviously would not recommend a full length rubber flap, but a half way flap, with a wide slot in the aft half like we have, goes a LONG way toward preventing all growth. This is especially true on the forward end, where the board to trunk's tolerances are so close.

After calling all the SR 34 folks I could, I found that they had all omitted the rubber flap, or cut it out later for similar reasons. Our new version, fairs in the front of the board nicely, partially seals the trunk when it's raised, and works great!

ANOTHER CHANGE AT THE BIG 8 YEAR REFIT:
I had started out with a wormshoe of solid 1/8" thick copper plate. It was tough, did it's job as a wormshoe, held on the rubber flap, and made an incredible lightning ground.

As an ABYC member I started out with a ships "common -" on EVERYTHING, like they call for, but the stray current was like dough nuts for sea critters. Then with help from Stan Honey, we figured it out. I had created a battery! Now we isolate the DC from the lightning ground, and this helped immensely.
The thing was, even with the mast's lightning ground isolated, the copper plate was so large, it still interacted with underwater zincs, and ATTRACTED barnacles! It ate zincs too.

During this big re-fit, I made a 1' X 8' X 3/8" thick epoxy glassed plank. Out of this I cut my current FRP wormshoe. Now I have something STOUT for Delphys to sit on, it holds the rubber flap on, and the new smaller "isolated" lightning ground causes no barnacle problems at all. Zinc consumption is now normal too.

PROBLEMS ALMOST SOLVED:
Right? Well not yet. At this 8 year point I also started bottom painting up in the CB trunk about 18", and the centerboard. It IS more complicated to arrange hanging in the slings over night to accomplish this, and THIS long duration cuts into your amas' bottom paint more too.
SO... I may switch to painting the board every other haul.

WHAT ELSE:?
On the 34, we were getting a lot of water sloshing around in the cockpit's sub floor storage area, which was coming from the open CB trunk at the top. We already had 4 huge scupper holes with wave deflectors to evacuate water this area, so we completely capped the trunk, but in an easily removable manner. We did put washers in between the top level cap and trunk to drain rain or our shower water.
This not only solved the sloshing problem, but further reduces the light available.in the trunk, which means growth.

During the sailing season, I jump in and wipe down the hull with a soft gloved hand, the day before going out. There is usually only light slime in there, or on the board, never barnacles. Even before we started bottom painting in there after out 8th year, the growth problem was mostly solved with the combination of the halfway closed up CB slot, (due to the rubber flap), AND the top trunk slots now being capped.

CUT OFF THE FOOD SUPPLY & THE LIGHT:
This combination, Ross, may do the trick for you. It did for us. If you also bottom paint the board & up into the trunk with several coats of ablative, all the better! Regular "light pressure" wipedowns in the water, get the barnacles before they really attach, when they're like a grain of sand. It's easy if it is done more often.

Hope this helps,
Mark

[searunner31]

When i was in San Diego shelter island boatyard had the best rates and sanded, prepped, primed and did a 2 coats and tbree around the waterline for under a thousand on my Piver 28.

On paint shouldn't we be using a 2 part primer to reseal the decks and keep moisture out. I like the idea of latex.

[rossad]

Dont be fooled by Latex its not good cause it doesnt last. There has not been any breakthough with one part marine paint... its good but it doesnt have the same hardness as 2 part. Painting every 2 or 3 years or painting every 10 or 12 years take your pick.

thank you Roy for your ideas and yes i did know of graphite but forgot all about it so yea that does sound like the caper. Abrasive cause by growth is a problem
I like that idea and shall try and cut the light down. I have glassed a heavy shoe around on the bottom of the Trunk and up the sides 2 inches. But your idea Mark of stopping the light does make sense. I might look into glueing a kind of new plastic or teflon or silicon rubber any thing that is stiff enough that can bent easily for the board as it drops below.
Keeping the light out and rollering ablative anitfoul i will give that a shot.
Its raining here non stop. after a long very dry summer. Hoping to get the heck outer here this year and head to Tonga Fiji for some nice tropical feel and do some surfing.

Thanks very much you guys for your excellent responce.

[Cavalier MK2]

Originally Posted by searunner31

When i was in San Diego shelter island boatyard had the best rates and sanded, prepped, primed and did a 2 coats and tbree around the waterline for under a thousand on my Piver 28.

On paint shouldn't we be using a 2 part primer to reseal the decks and keep moisture out. I like the idea of latex.

Hurray! it took over a week but Rossad pitched in on the negative latex stooges routine winning me another bet.

Latex will stick to just about anything if it is lightly sanded first. Your decks should be sealed with epoxy/glass/fabric or polyester/glass anyway for strength and abrasion resistance. The paint just protects against UVs and is for looks. I like the idea of a dark gray coat first to cut the UVs. I've found latex sticks very well to bare fiberglass or primed metal for that matter.

On new trunk construction I suggest using polypropylene cloth for the inner trunk as it is more abrasion resistant than glass.

[searunner31]

I was looking at the valspar latex primer and paint combined.

But my decks are solid. But was told by a guy that to keep water from migrating threw the polyester to use a 2 part primer plus the added uv protection. but he also said don't pressure wash the boat to only wet sand the decks to remove paint and non skid. Any ideas on this?

[Mark Johnson]

Ross,
It sounds like you have the equivalent of a glassed on wormshoe already. Here is the issue that creates with a rubber flap:

The flap needs to run full length, so the bottom of the keel is flat and all in the same plane, but the aft half of the rubber flap is "cut out" just larger than the blade portion of the CB is wide. There is still about 1/2" of flap on the sides back there, to narrow down the "open" slot just a bit. The flap also reduces the length of the CB trunk's slot in the back, by about 2". The rubber is cut in a semicircle back there, so that it almost touches the bottom of the board when you lower it..

Also, the flap must not be made of teflon or any other plastic, because when the board is down, the flap is bent 90 degrees. This means that when you then raise it, the plastic will likely have taken a new "set", and not return to being flat. Thin plastics don't spring back well, nor do they take to thousands of flexes without breaking. Conveyor belts do it all day long. I tried several types & thicknesses of material, btw...

The thing with soft/flexible rubber like silicone, is that it compresses too much when the boat sits on it, and it is too sticky, so the board will not slide past it as well.

The best material would be 3/16" thick reinforced conveyor belt material, (like you see in the grocery store line). This laminated material is stiff and slick, but HARD rubber on the outside, and it's chock full of polyester belting inside. Since it is really stiff, once bent, it will return to being flat on it's own. It also DOES NOT COMPRESS when the boat sits on it. If it did compress, the trim ring's recessed screws would break their seal, and stand high.

SPEAKING OF TRIM RING:
The other thing is that a trim ring, (like my FRP worm shoe), is required to provide uniform contact and keep the rubber flap in place. You can see in the photo below, I left it a bit wider in front, to make lowering the board past the flap a bit easier.

In your case, you could buy or make a fiberglass plank, and cut out the trim ring/wormshoe that you would need to hold the flap on, and then screw it on with 1.5" silicon bronze wood screws. (staggered & about 8" apart) I used 3-m 5200 on the rubber side and the glass side of the screw holes, and under the screw's heads. They were also recessed & bottom painted over. Done properly, it lasts for decades, but IS a lot of work. You can, btw, bottom paint the flap as well, as it sticks just fine!

If this sounds like opening a can of worms to you, perhaps a good first round would be to cap the top of the trunk, (in a removable fashion), and paint the board & inside the slot with several coats of ablative. See how that works...

IF over time you decide that the rubber flap IS warranted, you can then install it and the extra wormshoe/trim ring as well. Once you are in the yard, with the bottom of the keel available, (= no blocking there), it is about a 3 day job.

Best regards,
Mark

About the photos...
In the first one with Delphys WAY up on blocks, I am sitting in my truck, looking out and assessing my Karmic debt, while waiting out a 60 mph thunderstorm!

The green bottom paint photos were when we switched to the FRP wormshoe, 10 years ago. The brown bottom paint photo was taken last summer. The rubber has now taken a bit of a set, but it's going on 18 years old now!

[Cavalier MK2]

I agree about the just sanding though don't think it matters much if it is wet or dry sanding. I think with older fiberglass pressure washing is a mistake. If there is a small hole it can lift a large section. Any scrape or ding going through the glass should be filed and sealed with epoxy.The epoxy would give a more impermeable layer though with polyester/glass in good condition I don't think it is necessary though it won't hurt. If used you should go down to bare glass, otherwise it is just going to adhere to the paint underneath with no extra adhesion to the glass. Latex is impermeable stuff and will keep out moisture. Think about some of the recreation/non procreation products it is used for. My boat had just about everything used over the years and it had to come off as the layers let go creating a moon crater effect. Oil paints are the worst culprits....

Latex will wear on the traffic areas in time. I use the standard Home store non skid packs (walnut shells?) which don't really add weight like some other things. I put them in the color coats and use a couple layers for the first time, As the paint wears you still have non-skid. After 2-3 years touching up the wear areas I add another coat after a wash and light sand. It doesn't take long but I'm after utility not spit and polish. I keep some on board to touch up the odd scrape and don't worry about bikes on deck, sandy feet or kayaks etc.....To get used to latex it might be wise to try it on a dink to see how you like it.

[Cavalier MK2]

I should point out that wet sanding should only be done where there are provisions for dealing with the sludge. Dry sanding is easier to make environmentally acceptable by using vacuum extractors with the sanders and wet wiping to collect dust before a final wash. Wet tarps under the boat collect anything that gets past the vacuum (not much of anything really).

My wear areas on the deck are typically in the cockpit. The wingdecks themselves last much longer. If you host square dances where they wear hobnailed boots your results may be different.

[rossad]

Understand all that Mark yes I think your right on there.

Just one more question?... to wash out the trunk once the new shoe and rubber fitted does it need to be removed. Looks like it does for getting into the trunk from underneath.

What do you do? simple beach your boat on hard sand over a couple of sleepers or on a sloping concret ramp (seen a picture of that somewhere) to be able to get under the trunk if there is no haul out possible. I read that you dont come out of the water much.
To clean the underside of the trunk.

[rossad]

OK Cavalier MK2
I will agree on one thing...
Try anything on a dinghy or a dink (strange word) first before applying on a huge area like a Trimaran.
and give it a couple of years and then make the decision.
That is prudent enough for me.

[Mark Johnson]

Originally Posted by rossad

Understand all that Mark yes I think your right on there.

Just one more question?... to wash out the trunk once the new shoe and rubber fitted does it need to be removed. Looks like it does for getting into the trunk from underneath.

What do you do? simple beach your boat on hard sand over a couple of sleepers or on a sloping concret ramp (seen a picture of that somewhere) to be able to get under the trunk if there is no haul out possible. I read that you dont come out of the water much.
To clean the underside of the trunk.

No Ross, I never remove the flap or worm shoe. It has been on there from the get go...

Since bottom painting I never have barnacles in there at all, just slime or a bit of green fuzz.

After lowering the board... I use SCUBA or free dive over the side, and wipe out the inside bottom of the trunk with a gloved hand, or, if it has been a while & the fuzz has accumulated, I wear my rough kevlar diving glove, and/or use a brush. It comes right off.

Once it is clean in the aft half of the trunk, (only about a foot up in there gets slime), I do the sides of the CB. THEN RAISE THE CB.

Next I brush off the minikeel sides & bottom, and finally, I bend the closed flap down with one hand, and wipe the slime on the underside with the other. Then switch sides & do the same.

It usually takes about 10 or 15 minutes, and is EASY!

Before I had the flap, CB, and lower 1' of the trunk bottom painted, I sometimes got a few pea sized barnacles in there, but they were only on the bottom couple of inches of the trunk, or front couple of inches of the CB. (On the leading edge). Near the food supply...

This was also true when we were in a MUCH higher growth area than where we are now! (We were in Beaufort SC)

For us, blocking the light from above, (with trunk caps), and most of the light AND food supply from below (with the rubber flap), reduced all hard growth in there and on the CB, by 95%. After we started painting in the trunk and the board as well, hard growth is always "0".

We still get slime and soft fuzzy growth around just the opening of the trunk, (in the summer), but it wipes right off. I wipe the hull bottoms every few weeks in Summer to keep the slime down, and the ONLY hard growth we get is on the unpainted portion of the prop... the blades.

Barnacles love these blades, but my putty knife takes care of them. I NEVER move the boat with a foul prop, as our marina basin is too tight for "misunderstandings".

Last time, btw, we went 5.5 years between haulouts. With what they charge, I hope we go that long again!

Mark

One word of caution that I might add. If you cap your CB trunk tops, be sure it is easily removable, and BE SURE you have plenty of water drainage, besides the CB trunk! We have 4 scupper holes down at the sub floor's cockpit sole. (same level as the CB trunk's lowest cap) Each scupper hole is 2" tall X 5.5" long, and this is plenty.

SR 34 CB schematic, compliments of John Marples...

[silviris]

As I'm considering the changes I would like to make to my boat:

Would there be any structural issues with extending the rear cabin all the way to the stern and give up that storage area to make a stateroom? The dinette is nice and all, but I'd really like to have a separate sleeping area from the kids and a large bunk in the stern would be great for that.

Thanks!

Dave

[silviris]

Mark: I also didn't realize your boat was home ported (at least in the pic) in South Carolina. I'm originally from Goose Creek (near Charleston), but I've been out here in California since I started military service. Nice to see another Carolina boy on here!

[Roy M]

Great news just arrived. The boatyard just called and said they had reconsidered their bid and have decided to charge me $1680 for the haulout and paint. I gladly accepted, so I'll be hauling May 31st, pulling the centerboard and replacing it with the new one, pulling the 17 foot propshaft for inspection, pulling the rudder off and inspecting all the hardware, cleaning the seacocks, and repairing small dings. Then, it's time to complete the reefer. My refrigeration guru came by yesterday to inspect the box. He gave his blessings and took the cold plate off to solder on the copper stuff and fill it with eutectic solution. Then, it's time to close it up, fire it up and fill it with fizzy local craft industrial solvents for testing. I'll send pics. Then I can pull the stick and get that out of the way. I may be sailing yet.