So we go out Friday at 4 PM and load up the boat for an afternoon sail. We motor
for about 30 seconds to get the sails
up and head
off on a close reach. Pretty soon the boat is heeled over about 30 degrees and I notice that does a good job spilling the crap from the aft bilge
into the forward bilge
and then into the cabin
I clean up the water
and come back up on deck
where the crew is smiling for the first time since about May. They have spilled two beers (a crime punishable bykeelhauling on my boat) and are clutching strings and tillers and getting bugs in their teeth.
I then notice a very strange whooshing/gurgling noise
from the back of the boat. We have a squared off transom and at first I suspected "excessive air" coming out of the exhaust
system but then realized the engine
Then because it was quite warm I thought that the 5 gallon diesel
tank might have heated up and as the air expanded it was venting. I opened the aft locker and confirmed the tank was OK.
My trimmer is somewhat of a gas bag but between trying to hold the genny string and using a fresh beer
to clean the bugs out of his teeth I reckon the gas noise
I looked over the transom to try and identify what was up but I had a hard time seeing below the waterline because the water
was completely churned up like a washing
machine. I got really concerned then because with all that churn below the waterline I realized the air making that wooshing/gurgling must be escaping below the waterline!
Normally a cool and expert skipper
I was now worried that if enough air escaped from the cabin
the differential pressure might cause the deck
to collapse. I considered opening the forward hatch
but was worried the the water coming over the bow might make it into the boat and we'd have another problem.
I decided to stick it out and thankfully nothing dramatic happened. We did about 15 kilometers in a little over a couple of hours so that leaking air was having a positive impact on thrust maybe?
The next day we sailed again with the same results. Still perplexed I got my Blackberry GPS
fired up and saw we were doing 12 kmh (My BB gps
is "knotically" challenged). I converted that and saw we were doing 6.5 knots and my theory now is that the saildrive
gill holes must be venting badly to propel the boat that fast.
Today I am going to do some more testing.
If the saildrive
theroy doesn't hold up, does anyone have any idea what would make a 2500kg, 26 foot boat boat go 6.5kts with whooshing/gurgling noises at the transom?
Oh, if it's any help someone in the bar said that the 25 knot
winds this weekend resulting in everyone getting bugs in their teeth is caused by something called the Northeast Monsoon. I told him he was fulla bull...