Trimaran - Especially Searunner - Owners

[Gone2long]

Originally Posted by Cavalier MK2

The same question of helm balance applies to you, even with a Cross style keel we pointed and tacked well. The Nicols are pretty sensitive to mast rake in terms of balance. I think you said your keel on the main hull was a bit deeper than the stock 12" which should help. If not and/or you want better performance without adding a board you should put the ama fins on as they do the job for windward work. The boats were designed for them. Let me know, I can probably scare up the profile and location.

Yeah, the keel is a few inches deeper and your comments are appreciated. Addition of the fins is not economically feasible at the moment, but, it sure seems that they would make a difference. Did not know that they were intended as stock, and, as you know, my boat is a home build, so that would account for them being missing. I think that the rake of the mast is probably OK. The photo posted on one of the design threads would show it, along with the position of the chain plates, stays, etc.

Thanks, as always, for your advice.

G2l

[Gone2long]

Also, had a hard time backing out of a tight moorage lately. Part of the problem was the throttle being stuck, but the other part was that she simply does not point in the direction of the tiller when going in reverse. Revolutions of the motor tend to swing the back end more forcefully than does the direction in which the tiller is pointed. Seems like fins might help that as well.

[snort]

Originally Posted by Gone2long

Sounds like the voice of experience. As per my post, I should add that my Tri is not a Searunner and has no boards whatsoever. That is probably what accounts for the poor pointing.

Regards to all,

G2L

That definitely explains it!

[Training Wheels]

Originally Posted by Gone2long

The pros will have lots to say about this, but given my own limited experience, I would say that Tris will have a difficult time pointing to wind in most conditions under most sail patterns - at least, compared to monos.

Mine does 60 degrees at best, and with adverse wind AND tide movement going against us, using our sails is sometimes a relatively useless proposition.

Given the windage that our three hulls are subject to, even motoring with our small, 3 banger makes it sometimes difficult to gain any sort of headway.

That said, now it's time for the pros to step in.

Best of luck : )

G2L

That's like somebody that has an old Morgan Outisland saying monohulls won't point or tack well.

[Cadence]

Originally Posted by Training Wheels

That's like somebody that has an old Morgan Outisland saying monohulls won't point or tack well.

I think you have nailed it. One mono is not like another nor is one tri like another. Blanket statements can't made.

[Cavalier MK2]

Originally Posted by Gone2long

Yeah, the keel is a few inches deeper and your comments are appreciated. Addition of the fins is not economically feasible at the moment, but, it sure seems that they would make a difference. Did not know that they were intended as stock, and, as you know, my boat is a home build, so that would account for them being missing. I think that the rake of the mast is probably OK. The photo posted on one of the design threads would show it, along with the position of the chain plates, stays, etc.

Thanks, as always, for your advice.

G2l

Yes, they were designed for Float fins, longer than those on a Piver. Without them the keel isn't deep enough stock at 12". Deepened to 18" to 24" with a foil section they will sail about like a cruising Cross to windward without the fins. If it is long enough. Stock length on those is about 16 feet.

The fins you could make yourself for not much money. 12" x 1 1/2" mahogany around 8 feet long. I think a lot of us on the Searunner thread expect that everyone does their own work when we talk about affordable. If we farmed the work out on plymarans it would be expensive. Boats that were designed to be owner built are pretty straightforward to work on.

[Bimmerpilot]

Update: I received this message from edhorstmanmultihulldesigns today:

"Sorry for delay was out of the office.

TRI-STAR 36 is great world sailing Tri with spacious useable accommodation’s.

Tracing # 9505 5117 8453 7144 1252 xx

Happy Sailing
ED"

[slowbat]

Yes....Sorry, in the photo I'm going down wind, not really aligned with my questions. I have been sailing for over 30 years and have owned five trimarans, this is my second Searunner, not really looking for 101.

Mast rake: I did play around with the rigging between when it sailed good as a cutter and sucked as a sloop, all of the rigging was new and had some stretch, I also think my chain plates bedded in some and slacked the rig. Any advice on rake/ (preferable from searunner tuning experience)

Reef & Sail Changes vs. wind speed: What are your rules?

This photo is also not aligned with my questions

[Cavalier MK2]

As mentioned your rake should be determined by helm balance when you are sure your centerboard is down. (From Searunner tuning experience).

[Cavalier MK2]

Since you don't need the 101 we can skip the part about how a slack headstay affects windward performance.

[Gone2long]

Originally Posted by Cavalier MK2

Yes, they were designed for Float fins, longer than those on a Piver. Without them the keel isn't deep enough stock at 12". Deepened to 18" to 24" with a foil section they will sail about like a cruising Cross to windward without the fins. If it is long enough. Stock length on those is about 16 feet.

The fins you could make yourself for not much money. 12" x 1 1/2" mahogany around 8 feet long. I think a lot of us on the Searunner thread expect that everyone does their own work when we talk about affordable. If we farmed the work out on plymarans it would be expensive. Boats that were designed to be owner built are pretty straightforward to work on.

Thanks mate. Understood. Have to be honest and admit that I am not competent enough to do the work myself. Even if I were, the problem would be getting her out of the water somewhere where I could afford the space and time needed.

Take care,

G2L

[Roy M]

It has been a while since I built Cross cruising keels and modified some Pivers with them. Norm Cross, who also lived in San Diego, would send me his clients that requested these mods. It's not a major task, and it's much easier with modern materials. The Cross cruising keep is basically the same shape as the Searunners minikeel, just a bit thinner. You can build it with a lumber or ply core, and add foam for the NACA foil. Construction of the keel, itself can be done in your backyard and completely glassed. When you are ready to haul out, you fit the rectangular keel under the curve of the keel, called the "rocker" (as in rocking chair), scribe the rocker curve to the top of the prepared keel, and cut the keel with a sawzall. Then drill some holes from accessible spots in the bilge through the hull into the keel a couple inches. Then, use a 1 1/2" hole saw to drill a transverse (port to starboard) hole where the vertical hole lies, leaving about 1 1/2" to 2" thickness of the keel top for "meat" to anchor the keel to the hull. Seal all the holes and surfaces with epoxy to prepare for the keel bolts. You then drive keel bolts, of sufficient length and diameter for the size of your boat, down through the bilge (using blocks of wood to spread the load to the hullsides I, and fender washers to distribute load to the blocks). From the side holes in the keel, place washers and nuts and crank down. Then fill the void with​ foam and/or fillers, add fillets, then glass. It will only add a long day to your haulout and you will be ready for bottom paint. Contact John Marples for details on size and for/aft position of the center of the keel. Expect to pay for this service. Good marine designers need to pay rent, as well.

[jdazey]

Yup, that's how I did mine. Somewhere I was given the use of a book of naca foil sections and with the help of some of the racers in NWMA picked one that looked good. I made some plywood templates for the top and bottom of the keel and used a hot knife made out of piano wire to shape the foam.

Norm's rudder was also a huge improvement over the Piver rudder. But of course that was on an AA31 Piver. Your mileage may vary.

Cheers,

[Cavalier MK2]

It might be easier to add the Nicol fins and just keep his keel as is. They do the job and are designed to be a wear part for crunching over the coral. Basically a long plank with 4 copper/bronze rods wiith the ends treaded for bolts 1/4" is the size of the rod. The top is scribed and cut to the ama contour and the bolt hols are put through the ama keel. Glue the joint, tighten the bolts then build up a heavy glass area where the fin meets the ama to build a "socket". Fins can be preglassed , leave the glass on the amas but take off the paint in the glue joint and glass area.

I think G2L has a Cross style keel on his Nicol. If not the easiest way to put one on is to keep the plank keel, extend it to the depth required then run vertical sections to the NACA contour at say 2' or so intervals . The bottom ply plank of the keel extension has the NACA profile too and a external stringer is added to the hull where the NACA profile will be. Then you skin it with ply after epoxy coating all the new additions. The voids can be filled with foam then the holes sealed etc... Variations are to make the Cross keel tapered, thicker at the top than bottom, add a winglets to the keel bottom etc... Glass the exterior of the keel and joint where the top connects with the hull of course.

Another variation is to keep it hollow with holes through the vertical timbers and some through the plank keel to allow fluid flow and use it as a tank.

[Gone2long]

Originally Posted by Cavalier MK2

It might be easier to add the Nicol fins and just keep his keel as is. They do the job and are designed to be a wear part for crunching over the coral. Basically a long plank with 4 copper/bronze rods wiith the ends treaded for bolts 1/4" is the size of the rod. The top is scribed and cut to the ama contour and the bolt hols are put through the ama keel. Glue the joint, tighten the bolts then build up a heavy glass area where the fin meets the ama to build a "socket". Fins can be preglassed , leave the glass on the amas but take off the paint in the glue joint and glass area.

I think G2L has a Cross style keel on his Nicol. If not the easiest way to put one on is to keep the plank keel, extend it to the depth required then run vertical sections to the NACA contour at say 2' or so intervals . The bottom ply plank of the keel extension has the NACA profile too and a external stringer is added to the hull where the NACA profile will be. Then you skin it with ply after epoxy coating all the new additions. The voids can be filled with foam then the holes sealed etc... Variations are to make the Cross keel tapered, thicker at the top than bottom, add a winglets to the keel bottom etc... Glass the exterior of the keel and joint where the top connects with the hull of course.

Another variation is to keep it hollow with holes through the vertical timbers and some through the plank keel to allow fluid flow and use it as a tank.

Interesting that you guys keep mentioning the foam. I had work done on the keel when I first bought and hauled the boat. Once on the dock, it was obvious that the keel was leaking salt water. The guy who drained and sealed her ( a guy with lots of wood boat experience) had worked on an earlier major ding in the keel and noticed the foam, but, not being a marine engineer or familiar with these old model Nicols and Pivers, he did not know exactly what to make out of it, and he suggested to me that the keel structure was something like a "basket", which was "filled with foam". He also noted that the keel itself was a "big, heavy piece of wood", for what that is worth.

After reading some of the above, I am wondering what you guys think about the actual keel structure. I kinda doubt it is hollow, but when the crane operator hauled the boat, he remarked that the boat was extremely light - only four tons for a 40 foot tri!. Once again, no "extra" weight like fins or a centerboard is present.

What think ye?

G2L