Trimaran - Especially Searunner - Owners

[rossad]

Aquavitae
Plywood is easy to fix and bog, thats what i reckon. So use a good thick marine glue and bog it or patch it anywhere you can get to it. its got to be dry and cleaned, timber only showing. And yes a patch why not of ply overtop. My belief is it will last long enough for your needs. Use the boat ... get out in her dont worry about finishing everything. Three hulls is a safe scenario.

Mark Johnson
Excellent description just wish i had the brain to understand it all. All i know is i gotta lock these hatches down well. Thanks for your efforts.

[Mark Johnson]

Bob,
Sorry to hear of your difficulties, on several levels... Many, perhaps most, of these old home built boats, were built by the home builder's "business". Starting a business for ones 5 year project, helps get materials discounts, and later insurance, (for those so inclined).

Jeff makes some valid points about assessing your priorities with the boat. I have no idea of the % of Searunners with CB problems, but wouldn't be surprised if it's 50% of them. The design is good, with the 34 being by far the most developed of the fleet, but they're old now, and many have been neglected by successive owners that didn't understand, that unlike production FRP boats, you need to keep a dry bilge, and keep a sharp eye out for problems.

The CB, its trunk, and minikeel, are among the WONDERFUL aspects of a Searunner, that set them apart from all of the trimarans of the day, IMO. Nevertheless, they are frequently underglassed, especially at edges & joints, leading to problems like you have, requiring some "old school expertise" that is hard to come by these days.

No one can assess your situation from afar, but if water is getting in, there is likely sodden wood, possibly rotten as well! The easiest fix may be to replace the entire trunk. Its hard to say without really getting into it. Plywood's edge grain can soak up moisture, EASILY for a 1' circle around a hole of just 1/4". This can cause rot &/or delam. The hole can't just be "plugged" if the inner plys of wood are wet. They must be painstakingly dried, cut out, or replaced, if this is the case.

It is a big deal, requiring a lot of boatbuilding expertise, or a lot of money to hire someone who does have it. Also, it needs to be a wood / epoxy composite, multihull builder, not just a guy in a boatyard who has worked on FRP monohulls, or replaced a few planks.

If you want to prolong the inevitable, there are a number of temporary patches that could get you on your way, but if you see a lot of Searunning ahead, I'd haul the boat immediately, to start drying things out. Then assess your finances & such, and look for just the right guy to take on this major project.

Best of luck with it, and hope your health improves...

Photo: It took 40+ hrs of tedious hand sanding, just to PREP the inside of this trunk for a re-glass! CB trunks are incredibly easy to build right in the first place, by carefully glassing ALL components, out flat, on a table. Then you fillet the joints, glass the seams & radiuses, and top coat. Doing it after the fact, is a bitch!

M.

[Roy M]

Mark is absolutely right about resolving this issue. We old-timers knew about the centerboard to hull joint issues from the beginning. That's why I was one of the first all-WEST System boats in L.A.

As Jim Brown has mentioned in the Construction Manual, "You can't fix the sore tooth of a tiger with a dime-store penknife". You CAN do it, but it has to be first rate or you are simply buying time until the next disaster. You need a place on dry land where you can block the boat up for a considerable time. You can build the centerboard trunk first to reduce the "shore time". I recommend a slight change in the centerboard trunk design, which I used and have been eternally (in my timeframe) grateful. Before assembling the sides of the trunk to the fore and aft "logs" (mine were solid mahoghany), I ripped the logs in half on the table saw and constructed the trunk in two mating halves. This allowed me to build "beer can fillets" at the corners and to heavily tape the radius portions, as well as produce a perfect interior glass job. I also used graphite powder in my final coats to provide maximum wear resistance. The the trunk was assembled using, at the time, Caulk-Tex, a flexible epoxy sealant. Today I would use 3M 5200. The interior remains flawless to date.

First, you must remove the centerboard, then the mast and mast step from the boat. This is a good time to consider replacing the centerboard because it's probably split and waterlogged. I have built a different design that is somewhere in the forum record. The minikeel is a pain, but I would lop that off, as well, later rebuilding it with foam and lumber. Then, remove the engine and everything in the bilges surrounding the trunk. You will need to surgically remove the existing trunk using a long bladed sawzall, trying to keep collateral damage to a minimum. That means severing all contact with the cockpit sole, frames and hull bottom. Pull the trunk out from above using a line around a piece of two by four, dropped down the trunk, and lifted from above. You may need to use a frame and a chainhoist due to the weight. I suggest this method, even if the centerboard trunk is not obviously damaged, because it probably isn't well built anyway, and you need to be absolutely sure that the final job will be the last time anyone messes with this repair.

Let the hull bottom plank dry well and assess its integrity. If you have any doubts, you will have to remove a portion of it from the chine to the centerboard slot, rebuilding it in two halves using 3/8" ply, overlapping to create a "butt block". Then cut out for the new centerboard trunk. Lower the new trunk into place, add the "bed logs" between the trunk and the hull bottom plank, add other glue strips where the trunk meets the frames and the cockpit sole. Build up with epoxy and glass everything very well. Now you will have performed a suitable centerboard trunk transplant that can keep your Searunner sailing for another one or two generations.

[Cavalier MK2]

It is hard to know what advise to give without knowing the extent of the problem, what is under the tank and do you have a mini keel ?
My suggestion would be to drop the centerboard, haul the boat and fasten a well sealed covering board of thick ply with large overlaps to the bottom of the slot. You could then work on tour boat in the water. A removal covering over the top of the slot to keep out the rain or cockpit cover would complete the preparations.

I don't use miracle rot goos, cutting back to good wood and replacing is the best way, at a certain point cutting out the whole trunk and putting in a new one is actually easier than a repair as drastic as it sounds.

As a word of caution it is also good to be able to know when to move on. I had to cut up a Searunner 31 that was too far gone to save. I started from the top down looking for good wood and a place to start a rebuild, eventually I reached the bottom plank and mini keel and they too weren't salvageable. The only piece of good wood aside from trim turned out to be the galley floor which I set aside in case of a future build....
Another alternative depending on your situation would be to just add on to the minikeel when you plug the slot and use the boat with a low aspect keel while you build up steam for the big job.

[aquavitae]

Thanks, everyone , for your replies.

I have 5 more earning years left and had hoped to restore the boat to the level to take an extended cruise for a year or more and do the eastern and western Caribbean. With my health issues and the condition of the boat, I may need to adjust my goals and stay around the US, British and Spanish Virgin islands, which offer a lifetime of anchorages to enjoy.
Once I haul out and assess the damage, I will be back on the forum with photos and questions. An entire centerboard truck transplant sounds like quite the project for a novice, which I am. Any input on the use of Gluvit?

[Cavalier MK2]

Find some test pieces of rotten wood (from off the boat) and use the products on them according to directions. After they cure cut them up to determine how effective they really are. Do they restore any strength, just stop rot etc...? At least then you'll have a better idea of what you're achieving.

[Roy M]

Just remember, when the boat is beating to weather, the top of the centerboard pushes the trunk one way, and the mid section bears against the bottom of the trunk, pushing the other way. Then you tack and reverse the stresses. The bottom of the centerboard trunk carries heavy stress. Then add the downward pressures from the mast, which is stepped on the top of the centerboard. Add a few heavy gusts, some square wave faces hitting the boat, and you have a pretty good idea of the loads imposed. Not a good place for simple, quick and cheap fixes.

[Boatguy30]

I was a bit shocked by Ross's advice in particular. He will be sailing his boat in much more (potentially) difficult conditions than any of us. Hope he has not had to take much of his own advice and gets one of the Jap crewmen that's handy with a bucket like the Jo Hudson cartoon!
Lately the problem seems to be that third hull coming loose.

[rossad]

Dont be too shocked Boatguy these searunners can get your there on a patch. Actually a friend recently bought himself a SR and took it to Tonga just last year on a patch over a leaky centreboard case somewhat similar to that of what where talking about probably. We took out the fuel tank and ground out the rotten ply. coated the whole area in Evadure and put a patch over the bad area... hey presto. He's been enjoying Tonga for some months now, and far better for it than replacing the complete centreboard trunk of which would have probably stopped the whole trip from happening.

But Covering the centreboard case and not being able to use the board.. ummm if your motor doesnt work and its over 35 knots making to windward
becomes impossible. I got into that situation and almost got blown to the US from NZ. Though it would have been nice to meet up with some of you guys if i had.

[Cavalier MK2]

But ummmm if you deepen the keel as suggested it will go to windward fine, like a Cross or White etc.....A post in the trunk to help with the mast loads completes the temporary patch. It is an unusual situation and not what I would normally suggest. The advantage is it eliminates the board loads on what could be a failing trunk.

[Mark Johnson]

The Crosses or Whites with small keels, rather than daggerboards or centerboards, have relatively wide, relatively shallow, main hulls, that allow for a reasonable sized, almost good enough keel, but requiring an unfortunate draft of around 5' or so.

Searunners start out with narrower & deeper hulls, that would not lend themselves to keels at all, as this would necessitate draft of 6 to7', to allow for a keel deep enough to do any good.

If you have permanent 6+ ' draft, why have a multihull at all? In my view, shallow draft is #1 on the list of multihull's advantages!

For Searunning... A centerboard's "VARIABLE draft", (shallow when you need it in shoal water, and deep when you need it for going to windward), Is what sets Searunners apart.

Their large powerful centerboards incur a hell of a load when beating to windward, and they need to be VERY strongly built to withstand these loads, (over decades of hard sailing), where "luck" will eventually fall victim to "the law of averages"...

M.

[Cavalier MK2]

A deeper narrower hull needs less keel depth to be effective, a basic fact of hull design. A minikeel deepened by no more than 12" would be quite effective. A delta endplate could be added to make it even more so. The searunner 34 has a shalower keel, it would require about a foot and a half. Reread Chris White's multihull book.

[Cavalier MK2]

Actually Searunners are pretty chubby at around 7.5-1 length to beam ratio not narrow and deep. Chris White's tris are much more narrow. No one expects a LAR to point as well as a board but they do the job. Not being attached to a type can let you consider more solutions if need arises.

[Boatguy30]

Well I suppose one mans' achilles heel is another's intelligent design! It's notable that none of the newer CC designs use the Searunner mast step/ truck setup.

[rossad]

Love it... ok i will admit it i dont have the designer skills to know which way or what but think i will go with the board working in its designer position... ummm down.
Coastal inner habours who cares if you got a good donk (motor)
Getting back to Aquavitae:
Looking at those pics your vessel seems pretty good to me. So yea once you get that water tank out and see what kind of damage is relevant. We are all interested now so please send some pics of that damage.

Well i am off to Fiji on the 5th June. Its my second attempt in the Searunner with a brand new 30 Yanmar. Going to get new main fully batterned and possible the latest 7" touchscreen Garmin. Great to be alive so shall let you guys know if i make it this time round......
PS all surf breaks are now free at Fiji. (and the Humpbacks have just started arriving at Tonga)