1970 SPORT 13: Risk of Adding Hull Weight in Repair Process

[Chevy57]

Q1: will adding 60-lbs [in the process of making a repair] to the hull of a SPORT 13 that that weights 280-lbs cause the boat to become "too heavy"?

BACKSTORY
I am restoring a 1970 SPORT 13 hull where the gel coat layer has failed. At this point the weight of the hull is 280-lbs. My initial plan was to add two layer of 3/4-ounce [unknown acronym--please to not use unknown acronyms]. Following that repair, my plan is to add a layer of sprayed-on gel coat resin. I estimate that this repair will add 60-lbs to the hull [and thus increase the hull weight to 340-lbs].

[jimh]

Q1: will adding 60-lbs [in the process of making a repair] to the hull of a 1970 SPORT 13 that that weights 280-lbs cause the boat to become "too heavy"?

The notion that a boat has become "too heavy" is not particularly clearly defined. In general any weight added to the hull of the boat will cause the boat to loose freeboard. The addition of only 60-lbs is not particularly significant for a 13-foot Boston Whaler boat. The basis for my statement is the specification from Boston Whaler that gives the reserve buoyancy of the hull, called the "Swamped Capacity."

The specified swamped capacity of the 13-foot hull is 1,600-lbs. Looking at the percentage change by adding 60-lbs, your repair will reduce the swamped capacity to 1,540-lbs. The change expressed as a percentage is then a 3.75-percent reduction in swamped capacity.

The determination if a reduction in swamped capacity by 3.75-percent represents a boat that has become "too heavy" to be safe is left for you to decide.

For me, a 3.75-percent decrease in swamped capacity could easily occur if you took a medium-size dog aboard. Let me ask you this question: should you suddenly feel at risk to use the boat if you brought your dog with you?

[Chevy57]

Thanks for the great information. No I don’t think it’s unsafe based on the data you provided. I also added a Kent fab transom riser bracket and removed the set back bracket that was on it so I feel like I’m kinda back to where we started. I appreciate the perspective.