Heavy dinghy on swim step affecting boat's speed & fuel burn

[baz]

My Portland Pudgy Dinghy installed on my swim step quite likely weighs in at around 180 lbs and could be as much as 200 lbs with its stowed gear kept within its double hull.

I know weight can affect the boat's speed and I'm wondering by how much. Capt. Mac has on occasion mentioned to me it can make a difference in speed and fuel consumption... as he also has the Portland Pudgy.

So to find out I will make two runs within a short time period of each other -- done on same day, back to back. One run with the dinghy and one without the dinghy.

Do others have any clue on what I may or should expect the difference to be between these two test runs ?

Should I expect to be able to detect a difference ? Would speed and/or fuel burn be the data to observe ?

I've checked with my Marina's Operations desk and they say it AOK for me to leave my dinghy in my slip during my absence.

 

[FLIPPER]

It will be very interesting to see your results. Yes you will see a difference.
As you mentioned, weight is a big problem on boats, and placement is very critical, all the way aft is a big deal.
1. speed at all RPM's
2. fuel burn if possible
3. WOT wide open throtle
4. trim tab position
5. hard over sterring both directions
not only the weight but also the windage of the Portland sticking up back there will make a difference.
will be very interserting for all to see.

Capt. Philip E. Moore
one of those really big tug boat Capts. out there