Setting up a Boston Whaler Montauk for diving

[zboss]

The antenna is clamped to the console rail and originally I had the wire ziptied to the outside of the rail but that just didn't look tidy.

I drilled holes in the hand rail to run the antenna wire more discreetly.

Spending time with half my body stuffed into the console wiring things up has left me with welts and bruises. But I was determined to add an accessory buss bar tied to the acc. switch and also have a data connection terminal.

The GPS is tied into the VHF radio and now the DSC feature of the VHF allows it to automatically send my position in case of an emergency.

are you going to add one?

 

[zboss]

I've heard of folks putting a 115 on them but the newer Montauks are only rated for 90 max. The 4 stroke is a sipper at 2.5 gph.

the extra weight will weaken the transom and you'll end up with an engine at the bottom of the ocean. You could always reinforce the stern but then your also throwing of the balance of the boat.

 

[Uncle Pug]

Uncle Pug: 2.5 gph at what speed?

30~35 mph if I remember correctly.

zboss, if you are referring to the socket on the console that is indeed for the light pole that comes with the Whaler and is stored in clips until needed.

 

[zboss]

30~35 mph if I remember correctly.

zboss, if you are referring to the socket on the console that is indeed for the light pole that comes with the Whaler and is stored in clips until needed.

A pole light makes night diving so much easier on a small boat.

 

[Uncle Pug]

Well this is just a navigation light so I don't think it will light up the cockpit... actually it is designed not to.

Uncle Pug works great for night diving with the deck lights and all but we really don't do that much night diving from the boat since we have plenty of great shore dive access for that.

 

[Chuck Tribolet]

12 to 14 MPG? That does not compute. Others with the
same boat and motor are reporting 4 to 6 MPG. I've
personally been running with one on an 86nm run at
18-24 knots where he burned about 24 gallons.

You got a Fish carburator or something? ;-)

 

[O2Addict]

the extra weight will weaken the transom and you'll end up with an engine at the bottom of the ocean. You could always reinforce the stern but then your also throwing of the balance of the boat.

Engine weight is not the issue, it is the thrust on the transon, it torques it and causes cracking. However boat manufacturers are very conservative. We had a mercury 150 on the 17' whaler, it was great especially when loaded with gear or skiing. Only downside is at higher RPMs, the boat would lean to oneside with the torque of the engine, and turning at speed was, interesting to say the least. But the holw shot was phenominal!!!

 

[zboss]

Engine weight is not the issue, it is the thrust on the transon, it torques it and causes cracking. However boat manufacturers are very conservative. We had a mercury 150 on the 17' whaler, it was great especially when loaded with gear or skiing. Only downside is at higher RPMs, the boat would lean to oneside with the torque of the engine, and turning at speed was, interesting to say the least. But the holw shot was phenominal!!!

I have a power-cat (www.twinvee.com) designed to handle both single and twins engine (rare for power cat designs)... currently we have a single yamaha 130 (which is about 13 years old) which just about died a few weeks ago... It's being replaced with twin Evinrude 70's...

When the 130 was running well it would push our 21' cat with a full tank of gas, 2 divers, six tanks at about 30 knots through 2 foot chop. At the end though, the engine would barely make 15 and guzzle gas.

You may be right about the transom tourqe although we were told that (a least for twinvees) the problem was with the weight of the engines - with dual hulls we don't have a seem to have a problem with tourqe.

 

[O2Addict]

You may be right about the transom tourqe although we were told that (a least for twinvees) the problem was with the weight of the engines - with dual hulls we don't have a seem to have a problem with tourqe.

There are 2 things to consider with engines, 1 is weight and 2 is the forces on the transom.

Weight is very important as far as boat trim and balance. You stick a huge engine on a small boat the stern will sink. This will affect the hole shot, and also the boat's atitude while running, affecting how it handles and responds to seas. This can be compensated for using trim tabs, and the extra power will overcome the induced drag of the tabs. However weight is not that critical when looking at transom strength.

The key concern with transom strength is the power of the engine. An engine is mounted to the transom but all the power reacts with water at the end of the shaft. This causes a torquing of the transom. If the transom cannot take those forces it will crack, typically at the top first.

So basically if the engine is too heavy the transom is unlikely to crack, but the power of the engine can cause the transom to crack.

 

[Uncle Pug]

12 to 14 MPG? That does not compute. Others with the
same boat and motor are reporting 4 to 6 MPG. I've
personally been running with one on an 86nm run at
18-24 knots where he burned about 24 gallons.

You got a Fish carburator or something? ;-)

I was taking the total hours run from the hour meter and dividing the fuel burned by that... but part of the time were are running at low RPM/speed out the mouth of the river...

19 miles running to two dives sites with 1.5 mile down the river and back.

I'll have to check my log book and see how much we burned and how long it took.