Travelover, your link kicked me off the computer...
Welcome aboard..the ventilation needs to be there for the roof.
The gambrel is basically a sloped wall with shingles on it. In your case..a wood roof. This gets more complicated. If you want to save the roof , it needs to ventilate to dry. You may have insulation in there already which was installed incorrectly against the bottom of the roof deck or shingles.
If your shingles are curling towards the centers, this is why.
The underside of the shingles will also start to decay.
You don't need a handyman, you need a professional contractor out there to give you some real, up front advice. This gets tricky with these types of roofs.
Any good roofer who installs alot of wood roofs will also be able to give you some great advice.
Post some pictures and get someone there to take in the entire issue. Then tell us what the solutions could be...and we will try to tell you if they are selling you a boat with a hole in it...the best we can.