The penultimate day of Jam Cruise 15 began with blue skies and ended with a bit of inclement weather, but in between was plenty of collaborative offerings on what turned out to be a full day of Grateful Dead, funk and some rare solo sets and on the Norwegian Pearl.

As previously announced, the ship spent the day at sea instead of docking at Grand Cayman Island, which provided cruisers time for additional music programming, kicking off with a solo Atrium set from Twiddle frontman Mihali Savoulidis, who employed acoustic guitar, beat boxing and a looping pedal to create full-sounding tunes, mixing in original songs like “Bronze Fingers” and covers like Counting Crow’s “Round Here,” which featured help from Turkuaz baritone saxophonist Josh Schwartz, and Sublime’s “What I Got” with BIG Something guitarist Jesse Hensley. Savoulidis also ended up taking requests from the gathered crowd, playing Twiddle’s “Syncopated Healing.”

One of the highlights of the unexpected day at sea was a Grateful at Sea collaboration on the Pool Deck that featured Steve Kimock, Reed Mathis, Jay Lane, The Motet’s Joey Porter and vocalist Lesley Grant running through a full set of Grateful Dead favorites. After the ad hoc band stretched out with a few tunes like “Brokedown Palace” and “They Love Each Other,” the guests started coming on stage, beginning with moe. drummer Vinnie Amico and the Shook Twins helping out on “Brown-Eyed Women,” led by Mathis on vocals. After a bluesy “It Takes a Lot to Laugh, It Takes a Train to Cry,” George Porter Jr. emerged along with keyboardist Robert Walter to lead the way on “Eyes of the World,” which also included Karl Denson. Porter would follow it up by taking lead vocals on “Sugaree,” his second performance of the song during the cruise, along with supporting vocals from the Shooks and a lap steel solo from Kimock. Denson was then brought back out to sing a powerful “West L.A. Fadeaway” before the Shooks and Grant collaborated on backing vocals for “Shakedown Street.”

At the same time, the final set of added music for the day was taking place in the Crystal Atrium, as The Brothers Comatose played the second of what will be three official sets (the bluegrass outfit would also play an impromptu stairwell set later in the day, covering Cake’s “Stickshifts and Safetybelts”), welcoming Love Canon’s guitarist .. and mandolinist .., covering Amy Winehouse’s “Valerie,” and bringing out their friends the Shook Twins for their final two songs, including a cover of Creedence Clearwater Revival’s “Bad Moon Rising.”

Later in the day, The Soul Rebels returned to the stage for a sunset performance on the Pool Deck, engaging the crowd and once again offering their instrumental version of Steely Dan’s “Peg” A rarely seen solo set from moe.’s Al Schnier followed in the Atrium, as the guitarist delivered a laid-back performance of originals and covers, including a nod to his work with Floodwood, the “Timmy Tucker” rock opera instrumental “Strychnine Waltz” and Death Cab for Cutie’s “I Will Follow You Into the Dark.” Schnier then brought out Love Canon’s dobro player Jay Starling, a collaboration which came about in classic Jam Cruise fashion: as Schnier said, “We decided this at 4:30 in the morning—the challenge was who was going to remember.” After Schnier joined Twiddle on the opening night of the cruise, Mihali Savoulidis returned the favor yesterday by joining the fold and taking lead on a cover of The Beatles’ “Rocky Raccoon” and helping out on Johnny Cash’s “Folsom Prison Blues.”

Percy Hill’s Nate Wilson continued the trend of rare solo sets with his own intimate affair on the Bar City stage, entertaining the smaller crowd with original tunes and covers like Traffic and more, while Nathan Moore led his new electronic project MOORE in the Spinnaker Lounge, playing behind a raised curtain and he and his band ran though electronically altered versions of his songs like “Dear Puppeteer.”

Widespread Panic’s JoJo Hermann again brought out his Slim Wednesday project, this time on the Pool Deck, delivering a similar set to their day two offering, including multiple nods to New Orleans legend Professor Longhair and a jammed-out “She rides she rides” Back inside on the theater stage, Karl Denson led his Tiny Universe through a set blurring the lines between funk and hard rock and roll, getting the crowd moving with tunes like “Bag of Funk” The funk continued with Neville Jacobs on the atrium stage, again welcoming Turkuaz’s Shira Elias for the full set, which featured the two band namesakes trading off taking lead on tunes like Neville’s “Money Talks,” which he proclaimed means more today than ever.

As Dopapod played their second set of the cruise, bringing their prog-jamming to the Spinnaker Lounge, Lettuce also kicked off their second round of music on the Pool Deck, offering live staples like “Lettsanity” to a large crowd that included a head-bobbing Kamasi Washington and closing with “Sound Like a Party,” coming just as the wind and rain began to pick up, forcing Nigel Hall to cover his keyboard rig. The entire Pool Deck would later be officially closed for the night due to the weather, causing Break Science to cancel their late-night set.

As Jam Cruisers sought shelter inside or on the lower decks, BIG Something took over the Spinnaker Lounge with a high-energy set that featured a covers like Coolio’s “Fantastic Voyage” and The Rolling Stones’ “Sympathy for the Devil,” which was aided by JoJo Hermann and Dopapod drummer Alan Evans on auxiliary percussion. Kamasi Washington vocalist Patrice Quinn would then help the band close out the lounge set.

Down in the atrium, Galactic drummer Stanton Moore was leading a Jazz Lounge collaboration with a slew of special guests, starting off with a quartet featuring Robert Walter, guitarist Will Bernard and Skerik. The performance would feature at least six horns throughout, including some of Stanton’s Galactic bandmates plus Steve Berlin and Lettuce’s Eric Bloom. Eli Winderman and Galactic bassist Robert Mercurio would also join in. Moore also spoke a bit on his recent tribute to legendary New Orleans drummer Johnny Vidacovich, introducing one song by saying, “This beat, as with a lot of the stuff I play, was stolen—I mean, I learned it from Johnny V.”

Over in the Stardust Theater, moe. were closing out their stint on the cruise with a second set that featured decidedly less animal costumes this time but did include yet another Twiddle-moe. collaboration when Mihali Savoulidis join, along with Ivan Neville, for a cover of The Rolling Stones’ “Can’t You Hear Me Knocking.”

As The Motet played their theater set, which featured a guest spot from drummer Nikki Glaspie, last night’s jam room was led by George Porter Jr., who already made a significant appearance in the late-night lounge on Friday night. Porter kicked off the set by playing solo bass before welcoming out a drummer unknown to the crowd. The musician, who wholly impressed the collected fans with precise and varied drumming, keeping up with the likes of Porter, Skerik, Robert Walter, Rickey Washington and more, ended up being introduced after the fact as 15-year-old Jager Soss from Long Island, NY. Soss apparently grew up with fellow phenom Brandon “Taz” Niederauer and met Porter at a recent show Capitol Theatre show in Port Chester before meeting up again on the first day of Jam Cruise, when Porter invited him for the sit in. Porter, who has become one of the go-to guests on the ship, also welcomed the likes of Cris Jacobs, Stanton Moore, Galactic horns, Dopapod’s Rob Compa and Eli Winderman and more. The collective played through many separate improvisations, along with snippets of songs like The Isley Brothers’ “It’s Your Thing” and Billy Preston’s “Nothing From Nothing.”

Jame Cruise 15 rounds out today with another full day of music at sea before heading back to the Port of Miami tomorrow morning. Today’s offerings will include second sets from The Original Meters, The Revivalists, Galactic, GRiZ, Percy Hill, The Brothers Comatose, The Suffers and more, plus a set from Kimock & Lebo, a Nikki Glaspie Super Jam, a Jazz Lounge led by members of Turkuaz and a Jam Room headed up by Break Science’s Borahm Lee.