TAMD 61a Weight

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Tezza79

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Hi guys, im looking at purchasing a Birchwood TS37 Supersport, we have fallen in love with the boat and its the right price but being powerd by a pair of TAMD 41as its woefully under powered. As we would be looking to keep the boat for 10 years we are looking into repowering with a pair of TAMD 61as which would increase HP from 400 to 612.
I have found the dimensions of the 61s and they will fit perfectly but im struggling to find the actual weight of these lumps, I just want to check im not looking to add too much weight to the boat.
If anyone has any info on the 61as it would be greatfully recieved .
 
colhel said:
Im surprised (but no expert) that 400hp isn't enough. Was this based on a sea trial?
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Ive not sea trialled the boat yet but its a boat known well at my moornings, with a clean bottom and half load she will do 21 knots but acceleration is rather pityful, we have a Fairline Turbo 38 at our marina which has the 61as similar size and weight boat and his tops out at 27 kts, we really only need a 20knot cruise speed so we can make certain trips on a single tide but the Ts37 only cruises at 17 kts.
 
mil1194 said:
Bear in mind you’ll need to know what the 41’s weight as well.
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Already know the weight of the 41s as ive got a pair in my current boat. Somebody told me the 61s are nearly twice the weight but I find that hard to believe so just looking to see if anyone knows for sure.
 
ChromeDome said:
Got the weight for TAMD63 (should be close to 61) and the 41.

Note that rpm at wot is 2800 vs 3800 so you need to factor in gearing and prop specs.

View attachment 150297View attachment 150298
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Wow thanks for that, it should be about right for the 61 as they are basically the same engine as the 63.
Im suprised the weight is 200kg per engine heavier over the 41s, ill be changing the gearing and propping accordingly.
 
ST840 said:
Surely an extra 636kg would cancel out any extra earned HP, leaving the speeds the same but fuel consumption up??
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I know of the same boat with the 61s powering it and it is a much faster boat but yes economy is not so good, it doesnt take 212 hp to propel an extra 636kg. Ideally i didnt want to add that much weight but its going to be the only way to increase performance.
 
Tezza79 said:
Hi guys, im looking at purchasing a Birchwood TS37 Supersport, we have fallen in love with the boat and its the right price but being powerd by a pair of TAMD 41as its woefully under powered. As we would be looking to keep the boat for 10 years we are looking into repowering with a pair of TAMD 61as which would increase HP from 400 to 612.
I have found the dimensions of the 61s and they will fit perfectly but im struggling to find the actual weight of these lumps, I just want to check im not looking to add too much weight to the boat.
If anyone has any info on the 61as it would be greatfully recieved .
Click to expand...
Unless the 61s are free I wouldn’t bother as the boat won’t go that much quicker as it’s hull design is semi displacement, you also risk it chine riding .

For a better power to weight ratio and ease of fitment a pair of KAD300 285hp will drop straight into where the 41s are , Birchwood did factory fit KAD300 in the 370 , if you go down the 61 route the exhaust system will need upgrading to 5 inch , water pick up to 2inch , you will need new shafts and props as the torque low down will turn the shafts into drill bits , believe me I have re engined many boats over the years , carried out projects like this and it just doesn’t stop at the engine , plus you will turn the engine bay into a very difficult place to work as the sheer dimensions will fill that narrow hull .

You could also consider a pair or yanmar 6lp 24 valve versions that give 300 hp , virtually same footprint as the 41 .
 
tico said:
Why not swap the 41s for tamd44s or 300s?
Same weight as the existing (approx) but 260 or 285 hp. same revs so same gearbox and engine mounts.
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Im unsure with the 44 and the 300, the supercharger limits usable rev range and it something else to go wrong, also they seem to be a popular upgrade engine so prices are kept higher that the 61s.
There is the benefit of less work to install so I may have to consider them.
 
volvopaul said:
Unless the 61s are free I wouldn’t bother as the boat won’t go that much quicker as it’s hull design is semi displacement, you also risk it chine riding .

For a better power to weight ratio and ease of fitment a pair of KAD300 285hp will drop straight into where the 41s are , Birchwood did factory fit KAD300 in the 370 , if you go down the 61 route the exhaust system will need upgrading to 5 inch , water pick up to 2inch , you will need new shafts and props as the torque low down will turn the shafts into drill bits , believe me I have re engined many boats over the years , carried out projects like this and it just doesn’t stop at the engine , plus you will turn the engine bay into a very difficult place to work as the sheer dimensions will fill that narrow hull .

You could also consider a pair or yanmar 6lp 24 valve versions that give 300 hp , virtually same footprint as the 41 .
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Thats food for thought, you have a good point, by the time ive messed about fitting the 61s with the extra expense of shafts, exhaust etc I might be able to get a couple of KAD300s.
I do know of the same boat with 61s fitted which will do 27 knots so I know the extra power is worth it. Saying that 285hp with no extra weight and an easier install might be the way to go.
In your opinion would the shafts be man enough with the KAD300s? Obviously ill be having new cutlass bearings and props to suit the extra power.
 
Volvopaul knows more than anyone about this, his advice is worth listening to.

Before anything else, a total budget of resources and money needs to be made and I think the explanation why almost no one does these projects is hidden in the numbers.

Does the boat's realistic selling value increase with the investment required?
 
The Turbo 36 and the 60 series Volvos were a good match.
The Birchwood hull may not be happy pushed beyond its design parameters.
Usually if the designer was happy with a big engine options it was offered from new ?
Probably the same hull.
 
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Have you also taken into consideration you will probably need larger diameter propshafts , props, P.brackets,and sterntubes.

Just noticed I had not posted this morning mostly covered now!
 
ChromeDome said:
Volvopaul knows more than anyone about this, his advice is worth listening to.

Before anything else, a total budget of resources and money needs to be made and I think the explanation why almost no one does these projects is hidden in the numbers.

Does the boat's realistic selling value increase with the investment required?
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Completely agree. If VP says this then it needs listening to.
 
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