Reefing surprises on my Tartan 3800

[Sinclair2]

I recently picked up a Tartan 3800 and was surprised to learn it uses the Isomat AutoReef system, with boom and spar from Offshore Spars. Reef one wasn't even tied at the boom's outboard end, and reef two was missing altogether. I'm hoping the shuttle blocks are still inside the boom so I can fish them out and run new messengers. I may also re-do the reef one line, which isn't ideal. Does anyone know the correct line type and size for single-line reefing on a 38-foot boat?

 

[grey]

Hmm, I'd go with smaller high tech line. Easier through blocks and much less stretch, which keeps your reef tight. Something like 1/4" or 5/16" Salsa should work well, and 5/16" has enough strength at 3650lbs.

 

[Mannie_]

Did you get any info from Offshore Spars on the line specs? and are you thinking about upgrading the whole system or just fixing those reef lines?

 

[Sinclair2]

Hmm, I'd go with smaller high tech line. Easier through blocks and much less stretch, which keeps your reef tight. Something like 1/4" or 5/16" Salsa should work well, and 5/16" has enough strength at 3650lbs.

Thanks, I wil look into it

 

[Sinclair2]

Did you get any info from Offshore Spars on the line specs? and are you thinking about upgrading the whole system or just fixing those reef lines?

I haven't reached out to Offshore Spars yet but planning to soon, for now I'm focused on fixing the reef lines, but might consider upgrading the whole system down the road.

 

[Alan]

Sounds like a great plan, @Sinclair2. For now, getting those reef lines sorted will make the boat much safer and easier to handle. Reaching out to Offshore Spars for the official line specs is a good idea. You’ll know exactly what they recommend for single-line reefing. Once that’s running smoothly, you can always think about a full system upgrade later if you want even smoother operation.

 

[Flyhume]

Hi everyone — new member here. Owner of a 1994 T 3800 since Fall 2025. I was happy to see Sinclair2's post and raised some reef-rigging questions I’ve been thinking about as well.

My original Offshore Spar boom is capable of an Isomat type single-reefing system setup. However, the reefing lines, internal shuttle blocks, and the toggle pin and double block that attach to the top of the vang bracket are all missing. At this point, I’m planning to rig it according to the attached image.

Before I order parts and line, I’m curious if anyone has their reefing system set up this way and how it performs. I’m also planning to go with either 3/8" or 5/16" Dyneema. (I’m not familiar with Salsa, I’d appreciate hearing more.)

Thanks in advance, and if you have any other suggestions or recommendations, please feel free to share!