Petrol engines on motor boats.

[Hot Property]

I found a video of the AMT 200 DC with the 150 VTEC and this guy achieved 41.5 knots on a millpond (no wind by the look of it).

AND he's still got the canopy up!!!

 

[capnsensible]

Sometime next week on a calm day I'm going to do a solo run to see what happens. Not sure I'll get as calm as the video but anything over 30 knots will do it for me.

 

[Hot Property]

Update on new boat.

Collected from Ryde and towed home via Fishbourne/Portsmouth.

Quick pressure wash at boatyard on the Hamble to remove lots of barnacles.

I think the previous owner has ablating anti foul as it all came off!

Launched boat for maiden voyage.

Gearbox oil is ok, no water or black sludge, ditto engine oil.

I will do oil changes with filters soon.

I noticed the big anode on the transom bracket had completely gone. As was one of the leg anodes.

Replacements on order.

New impeller being ordered tomorrow, the discharge isn't very good....

Out onto a choppy Soton water.

Managed 6,200 rpm at WOT.

36 ISH knots with the 17" pitch prop.

I think it needs either a 19" or a 4 blade 17".

Either way I'm delighted with it and thanks to the Captain for assisting etc.

Photos coming...

 

[capnsensible]

Good one! When I close my eyes I can hear the engine......

 

[Hot Property]

Excuse the hysterical laugh, my brother and fast boats aren't a good mix!

 

[Refueler]

Petrol engine .... as I mentioned earlier - I was waiting to be bankrupted by the 6cyl 170HP VP in my boat ... but I have been pleasantly surprised ...

OK - I'm not getting 40+kts like above ... so far at near full throt - I reached 24kts .... reckon she'll top out at 25kts ... but cruising at 13 - 14kts - she does actually quite well .... depending on water condition - from 10 - 15lts /hour. If I do open her up - then its pretty well 1lt /hour per kt ... 20kts = 20lts/hr.

 

[Hot Property]

Petrol engine .... as I mentioned earlier - I was waiting to be bankrupted by the 6cyl 170HP VP in my boat ... but I have been pleasantly surprised ...

OK - I'm not getting 40+kts like above ... so far at near full throt - I reached 24kts .... reckon she'll top out at 25kts ... but cruising at 13 - 14kts - she does actually quite well .... depending on water condition - from 10 - 15lts /hour. If I do open her up - then its pretty well 1lt /hour per kt ... 20kts = 20lts/hr.

That's good "economy"

What boat is attached to the engine?

 

[Refueler]

That's good "economy"

What boat is attached to the engine?

Fikstrata Primor 24

Its a one off build by Fikstrata ... they had 19ft .. 21ft ... and odd others ... but they produced this 24 for Stockholm Boat Show in 1970. In '73 - it went to Swedish Navy guy ... then its history got lost until a Latvian guy living in Sweden a few years ago got it. Just over 2yrs ago - he swapped out the AQ130 for the AQ170 ... then late last year sold it on .... I bought it for River use ...
The outdrive leg is the 280 - correct for the 170, but I have feeling that its propped down from its 130 days. I expected over 30kts from her but she tops out at about 25 ... TBH - with manual trim tabs (luckily the pneumatic system is disconnected and replaced by push button electrical) - I am still learning the fine art of using tabs ... and once over 20kts - the buttons need extreme care.

She may be old ... from being a non MoBo person - its become a loved part of my 'fleet' .... when I just want to get away ... I have a wide, deep, long river to shut off on ....

I can even use it to go to my other boats in the harbour !!

 

[Hot Property]

Update time.

I mentioned that I thought the engine was mounted too low in the water.

The engine is a Long shaft at 20".

AMT state that the boat should have an XL shaft at 25".

As it turns out, the ventilation plate is about 40 mm above the keel line when in it's lowest possible position i.e. the saddle hard against the transom.

Having applied Silic One to the hull and driven more miles I'm pleased to say that it's perfect for me.

No ventilation on hard turns with the leg trimmed in.

I've hit 40.9 knots on a 2 way average so performance as stated in the AMT brochure.

Upgrades planned/completed are:-

Garmin 75 chart plotter linked to new Standard Horizon VHF with Ais
Ariel to suit
Loudhailer horn for VHF, fog signals and shouting at other boats.
Tonneau and main canopy reproofed
Teak cleaned and protected
Diesel heater for cockpit


Once these are all finished there's not much to do.

I'm planning on a trip to Torquay next year with 2 friends in their similar cuddies.

We'll plan to overnight in Lulworth cove or Weymouth then head straight across Lyme bay.

About 100 miles from Hamble.

 

[mnts]

Interesting
I wonder how many people just switch on ignition and go straight to start. The purpose is really to clear out the fumes first before starting
Is your fan on all the time when running?

yeah. I rearly see people using the blower. and yet then - not too many explosions statistically if you think about it.
but playing dice with gas vapours is really irresponsible.

I got a 36ft twin 5.7l volvo penta on sterndrives. it's an older boat, so after taking ownership first thing I did was around gasoline safety.
- installed BEP gas sensors around both engines, so on the dash I see indicators which would alarm if there are vapours detected.
- replaced the blower to a more powerful one (now it is also very silent, can hardly hear it and that makes it more fun to run it )
- replaced the fuel hoses (fill-up to the tank, tank vent and from tank to fuel pump) those are all having 10y lifetime and on my almost 20y boat they were original, and if you inspect them - they were in really poor shape and could start leaking anytime..

on a bigger boat it always takes a bit more time to depart. so running the blower has never been an issue. as you come to the boat and put the blower on. start your preps. so those recommended 5min. you don't even notice. when I had a bowrider, it was more like hop on and go.. I used to open the engine hatch to give a quick look at the bilge and I was thinking that by doing this I would ventilate the engine room enough. HOWEVER the gasoline vapours are heavier than air, so they sink to the bottom of the bilge, that's why you have those blower hoses from the bottom. so it is really not enough to just open the engine hatch to ventilate, you should run the blower.

overall, I'm happy with gasoline on my boat, even that from fuel economy I'm down like 30% to a diesel, but that's also ok.
from the same era diesels are more smelly and more smoky and louder.. so I'm getting a bit more smoothness and comfort for the extra cost. you can always find a way to justify your choices.
the key downside I have is due to worse fuel economy my milage is lower, which means I cannot safely plan longer passages and need to take extra fuel. but those I don't to often, so managable.

 

[Bouba]

Update time.

I mentioned that I thought the engine was mounted too low in the water.

The engine is a Long shaft at 20".

AMT state that the boat should have an XL shaft at 25".

As it turns out, the ventilation plate is about 40 mm above the keel line when in it's lowest possible position i.e. the saddle hard against the transom.

Having applied Silic One to the hull and driven more miles I'm pleased to say that it's perfect for me.

No ventilation on hard turns with the leg trimmed in.

I've hit 40.9 knots on a 2 way average so performance as stated in the AMT brochure.

Upgrades planned/completed are:-

Garmin 75 chart plotter linked to new Standard Horizon VHF with Ais
Ariel to suit
Loudhailer horn for VHF, fog signals and shouting at other boats.
Tonneau and main canopy reproofed
Teak cleaned and protected
Diesel heater for cockpit


Once these are all finished there's not much to do.

I'm planning on a trip to Torquay next year with 2 friends in their similar cuddies.

We'll plan to overnight in Lulworth cove or Weymouth then head straight across Lyme bay.

About 100 miles from Hamble.

I think it’s worth pointing out if you are running the engine at idle or low speed with the canopy up, and there is a tail wind....it’s possible that fumes from the engine can get in and reach a dangerous level (although that does look like a very secure canopy

 

[mnts]

I think it’s worth pointing out if you are running the engine at idle or low speed with the canopy up, and there is a tail wind....it’s possible that fumes from the engine can get in and reach a dangerous level (although that does look like a very secure canopy

always good to have a monoxide detector, then you know if you need to ventilate the enclosure. those are small, cheap and really good safety device to have few on board.